BG3.24 | Peatland management, restoration and conservation
Peatland management, restoration and conservation
Convener: Hanna Silvennoinen | Co-conveners: Bärbel Tiemeyer, Susan Page, Franziska Tanneberger
Orals
| Mon, 24 Apr, 08:30–12:30 (CEST), 14:00–15:45 (CEST)
 
Room N2
Posters on site
| Attendance Tue, 25 Apr, 08:30–10:15 (CEST)
 
Hall A
Posters virtual
| Attendance Tue, 25 Apr, 08:30–10:15 (CEST)
 
vHall BG
Orals |
Mon, 08:30
Tue, 08:30
Tue, 08:30
Peatlands are threatened by a number of anthropogenic activities such as drainage, peat cutting, eutrophication and climate change. Peatland restoration for conservation purposes can solve many problems related to drained peatlands and has been implemented for decades now. However, innovative management measures that sustain economically viable biomass production while reducing negative environmental impacts including greenhouse gas (GHG) emissions, fire risk and supporting ecosystem services of organic soils are only currently studied. Those management measures include, but are not limited to, productive use of wet peatlands (paludiculture), improved water management in conventional agriculture and innovative approaches in conservation-focused rewetting projects. Besides work on global change effects on unmanaged peatlands, we invite studies addressing all types of peatland management, i.e. agriculture, forestry and “classical” restoration, their integration into GHG inventories and their impacts on ecosystem services and biodiversity regionally and nationally as well as their integration into GHG inventories. Work on all spatial scales from laboratory to national level addressing biogeochemical and biological aspects and experimental and modelling studies are welcome. Furthermore, we invite contributions addressing policy coherence and identifying policy instruments for initiating and implementing new management practices on organic soils.

Orals: Mon, 24 Apr | Room N2

Chairpersons: Hanna Silvennoinen, Bärbel Tiemeyer
08:30–08:35
08:35–08:45
|
EGU23-8556
|
ECS
|
On-site presentation
Angelika Kübert, Mika Aurela, Juha Hatakka, Tuomas Laurila, Juuso Rainne, Juha-Pekka Tuovinen, Henriikka Vekuri, and Annalea Lohila

Boreal peatlands are a major source of global wetland methane emissions. With ongoing climate change, these emissions could rise sharply in future, further enhancing climate change. Yet, long-term studies evaluating the impact of climate change on boreal peatlands are scarce. We have monitored methane emissions at a boreal fen in Lompolojänkkä, Northern Finland (ICOS ecosystem class II site) for 13 years (2007-2019) using the eddy covariance technique, accompanied by measurements of abiotic and biotic variables, such as peat temperature, water level, and vegetation parameters. Peat temperatures strongly drove methane emissions, that is, methane emissions increased significantly with peat temperature. Year-to-year variation in CH4 emissions was correlated to year-to-year variation in peat temperatures. Annual variation in water levels had no significant impact. Our results confirm that peat temperature explains CH4 variation to a large extent. In this presentation, we will further evaluate the role of snow cover and melt on CH4 emissions in spring.

How to cite: Kübert, A., Aurela, M., Hatakka, J., Laurila, T., Rainne, J., Tuovinen, J.-P., Vekuri, H., and Lohila, A.: Peatland methane emissions in a changing climate: A 13-year time series of a boreal fen in Northern Finland, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8556, https://doi.org/10.5194/egusphere-egu23-8556, 2023.

08:45–08:55
|
EGU23-3889
|
ECS
|
On-site presentation
Olli Peltola, Olli-Pekka Tikkasalo, Pavel Alekseychik, Samuli Launiainen, Aleksi Lehtonen, Qian Li, Mikko Peltoniemi, Janne Rinne, Antti Rissanen, Sakari Sarkkola, and Raisa Mäkipää

Clear-cutting of drained peatland forests, as a part of the conventional even-aged rotation forestry, significantly disturbs peat soil biogeochemistry due to changes in soil physical characteristics and microbial activity. Achieving spatially representative estimates of GHG emissions from such a complex area is a challenging task. Accurate estimates of GHG fluxes following clear-cutting are sorely needed for national greenhouse gas reporting and devising more climate-friendly forestry practices for these production ecosystems, abundant in the Nordic countries.

In December 2021 we initiated continuous eddy covariance (EC) measurements of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) fluxes on a nutrient-rich drained boreal peatland forest (ca. 6.1 ha) in southern Finland. The mature tree stand dominated by Norway spruce (Picea abies) was clear cut in March 2021. The measurements are part of a larger research effort aimed at understanding climatic impacts of forest management practices on drained peatlands. Here we focus on interpreting the spatiotemporal variability of GHG fluxes from the clear-cut site using the EC measurements.

The clear-cut area was emitting N2O to the atmosphere throughout the measurement period, including the winter period. The emissions increased after snow melt and peaked during late July 2022. Despite CO2 uptake offsetting approximately one third of ecosystem respiration, the clear-cut area was a strong source of CO2 to the atmosphere during the year 2022 (2.0 kg(CO2) m-2 yr-1). CH4 emissions were small, yet clearly positive. The observed GHG fluxes showed clear wind-direction dependency indicative of spatial variability of GHG fluxes within the clear-cut. The spatial variability will be analysed based on detailed mapping of the clear-cut surface and footprint (i.e. source area) modelling, in combination with further scrutiny of the EC fluxes. Overall, these results provide the much-needed information on the GHG fluxes from such ecosystems and serve as a baseline for this site in the future.

How to cite: Peltola, O., Tikkasalo, O.-P., Alekseychik, P., Launiainen, S., Lehtonen, A., Li, Q., Peltoniemi, M., Rinne, J., Rissanen, A., Sarkkola, S., and Mäkipää, R.: Eddy covariance observations of CO2, CH4 and N2O fluxes of a drained boreal peatland forest after clear-cutting, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3889, https://doi.org/10.5194/egusphere-egu23-3889, 2023.

08:55–09:05
|
EGU23-15544
|
ECS
|
On-site presentation
Peat respiration in drained peatland forests under varying tree harvest regimes
(withdrawn)
Aino Korrensalo, Jani Anttila, Jyrki Jauhiainen, Raija Laiho, Aleksi Lehtonen, Päivi Mäkiranta, Paavo Ojanen, Mikko Peltoniemi, Timo Penttilä, Petri Salovaara, and Raisa Mäkipää
09:05–09:15
|
EGU23-7536
|
On-site presentation
Mikko Peltoniemi, Qian Li, Pauliina Turunen, Boris Tupek, Päivi Mäkiranta, Kersti Leppä, Mitro Müller, Antti J. Rissanen, Raija Laiho, Jani Anttila, Markku Koskinen, Aleksi Lehtonen, Paavo Ojanen, Mari Pihlatie, Sakari Sarkkola, Elisa Vainio, and Raisa Mäkipää

Greenhouse gas (GHG) emissions from peatland forest soils are associated with ground water table (WT) level, which controls the vertical distribution of aerobic and anaerobic processes in soil. It has been suggested that transition from rotation forestry with ditch network maintenance (DNM) to selection harvesting would be a feasible alternative to reduce negative GHG and water impacts of peatland forestry as it raises WT and reduces aerobic decomposition of deep peat compared to mature forests. Transpiration from remaining trees would keep WT low enough for stand growth and natural regeneration without DNM. We measured vertical CO2, CH4, N2O and O2 concentration profiles in two peatland forests to provide insights on the controls of processes producing and consuming gases in the soil after harvest-induced hydrological change. The sites located on nutrient-rich peatland soils in Southern Finland, were dominated by Norway spruce, and parts of the sites were selection harvested. Selection harvesting raised WT by 14 cm relative to non-harvested controls, on average. All soil gas concentrations were associated with the proximity to the WT, but their patterns and in-soil fluxes were decoupled. CH4 and CO2 showed remarkable vertical concentration gradients, with very high values in the deepest layer due to low gas permeability of wet peat. However, CH4 was efficiently consumed in the peat layers above the WT where it reached sub-atmospheric concentrations, indicating oxidation of CH4 from both atmospheric and deeper origins. Soils maintained these functions after selection harvest. Surface peat contributed the most to soil-atmosphere CO2 flux, but harvest treatment also modestly increased the source in deeper soil. No consistent differences were observed in N2O emissions, which were the least associated with other gases. Based on our results, selection harvesting in drained nutrient-rich peatland forests without other hydrological measures limitedly reduces soil net emissions compared to non-harvested mature stands.

How to cite: Peltoniemi, M., Li, Q., Turunen, P., Tupek, B., Mäkiranta, P., Leppä, K., Müller, M., Rissanen, A. J., Laiho, R., Anttila, J., Koskinen, M., Lehtonen, A., Ojanen, P., Pihlatie, M., Sarkkola, S., Vainio, E., and Mäkipää, R.: Soil CO2, CH4 and N2O concentrations and fluxes in peatland forests are associated with water table level - implications of selection harvesting on soil emissions, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7536, https://doi.org/10.5194/egusphere-egu23-7536, 2023.

09:15–09:25
|
EGU23-6364
|
On-site presentation
Annamari Laurén, Petri Kiuru, Mari Könönen, Elina Peltomaa, Jukka Pumpanen, Anne Ojala, Eliza Hasselquist, Hjalmar Laudon, Ivika Ostonen, Florence Renou-Wilson, Aaron Petty, and Marjo Palviainen

Planning of peatland management under contrasting economic and environmental targets requires application of ecosystem models that can account for complex interactions and feedbacks between biogeochemical, hydrological and forest-related processes. Here we present a further developed version of Peatland simulator SUSI (Lauren et al. 2021) that calculates formation, transport and biodegradation of dissolved organic carbon (DOC). We tested the new model structure against laboratory incubation results containing peat columns from Finland, Estonia, Sweden and Ireland. The drainage strategy (distance between ditches and ditch depth) is considerably different in all these countries: In Finland the ditch network forms a dense fish-bone pattern with an average ditch distance of 40 m, in Estonia the ditch distance is longer but the ditches are arranged to square blocks, in Sweden the network is often irregular, and in Ireland shallow ditches are spaced densely. Then we applied SUSI and assessed the impacts of changing ditch depth and distance on stand and soil C balance, lateral C flux and forest growth. We found that DOC export originated mainly from the close proximity of the ditches because the rate of decomposition is highest and the transport time is shortest. Further from the ditches, water residence time can be several months or even longer enabling biodegradation of a large part of DOC during the transport. The results revealed that even small slopes had a remarkable impact on WT, residence time and DOC export; and that the effect of the slope could exceed that of drainage dimensions per se. Overall results indicated that drainage strategy in Finland was particularly sensitive to changes in ditch depth and distance. In contrast, changes in irregular, sparse ditch network in Sweden caused only minor effects on forest growth, C balance and lateral C fluxes. 

How to cite: Laurén, A., Kiuru, P., Könönen, M., Peltomaa, E., Pumpanen, J., Ojala, A., Hasselquist, E., Laudon, H., Ostonen, I., Renou-Wilson, F., Petty, A., and Palviainen, M.: Effect of drainage intensity on lateral carbon fluxes in forested peatlands, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6364, https://doi.org/10.5194/egusphere-egu23-6364, 2023.

09:25–09:35
|
EGU23-6367
|
On-site presentation
Marjo Palviainen, Mari Könönen, Elina Peltomaa, Jukka Pumpanen, Anne Ojala, Eliza Hasselquist, Hjalmar Laudon, Ivika Ostonen, Florence Renou-Wilson, Ain Kull, Gert Veber, Virginia Mosquera, and Annamari Laurén

Lateral carbon (C) flux results from complex interplay of formation, transport and biodegradation of dissolved organic carbon (DOC), and is an important but rather scarcely studied component of the C balance in peatlands. Temperature and water table (WT) are the primary factors regulating peat CO2 emissions and the release of DOC. DOC dynamics in soil is complicated because the DOC storage is continuously increased by the decomposition of solid organic matter, but simultaneously decreased by biodegradation. Any upscaling of lateral C fluxes requires understanding these coinciding processes. We studied the effect of temperature and WT on CO2 emission and DOC concentration in pore water while incubating peat columns (diameter 0.2 m height 0.5 m) in laboratory conditions for eight months. Peat columns were extracted from drained forested peatlands in Finland, Estonia, Sweden and Ireland. WT was set to -0.2 m and -0.4 m distance from the column upper end. During the incubation, the temperature ranged between 18  and 34 ⁰C. DOC samples were extracted in monthly intervals from the columns using Rhizon soil water samplers. At the same time CO2 emission was measured from the headspace of the column. DOC biodegradation to CO2 and its temperature sensitivity was studied by incubating soil water samples in controlled conditions. The quality (aromaticity) of DOC was investigated with a UV-VIS spectrophotometer. The effect of temperature on DOC concentration was not straightforward unlike in the case of CO2 emission. DOC concentration increased steepest when the temperature exceeded 25  ⁰C, whereas with lower temperatures DOC was unchanged or slightly decreased. This can be due to different temperature sensitivities of DOC release and its biodegradation. Low WT resulted in high CO2 emissions and DOC concentrations. These results are important in developing ecosystem models accounting for lateral C fluxes and the effects of forest management, drainage and climate change in managed peatlands.

How to cite: Palviainen, M., Könönen, M., Peltomaa, E., Pumpanen, J., Ojala, A., Hasselquist, E., Laudon, H., Ostonen, I., Renou-Wilson, F., Kull, A., Veber, G., Mosquera, V., and Laurén, A.: Processes affecting lateral carbon fluxes from drained forested peatlands, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6367, https://doi.org/10.5194/egusphere-egu23-6367, 2023.

09:35–09:45
|
EGU23-2639
|
On-site presentation
Aleksi Lehtonen, Kersti Leppä, Katja Rinne-Garmston, Elina Sahlstedt, Pauliina Schiestl-Aalto, Juha Heikkinen, Giles Young, Mika Korkiakoski, Mikko Peltoniemi, Sakari Sarkkola, Annalea Lohila, and Raisa Mäkipää

Continuous cover forestry (CCF) has been promoted as an environmentally sustainable option for drained peatlands. The CCF management has been challenged due to potentially lower tree growth compared to traditional even-aged management, especially with suppressed trees that are released during a selection harvesting under CCF management.

Our objective was to quantify the time lag of stem diameter growth response of suppressed Norway spruce trees (Picea abies Karst.) after a selection harvesting compared to that of dominant trees. We also tested if the carbon assimilation of the trees increased immediately after selection harvesting. We used radial increment cores from suppressed Norway spruce trees to estimate the impact of selection harvesting on the diameter growth and intrinsic water use efficiency (iWUE). We measured carbon isotope composition (δ13C) of wood, to quantify how the reduced competition between trees altered iWUE and its components, the photosynthetic rate (A) and stomatal conductance (g).

The study was conducted in the Lettosuo experimental site on fertile forestry drained peatland area in southern Finland. Approximately 70 % of the initial stand area (18.5 ha) was harvested according to CCF principles by applying selection harvesting, and the rest of the area was divided to intact control area and to clear-cut area. In the study site, by selection harvest, trees were removed from multiple age classes, but especially mature trees individually or in a small groups were taken away to maintain uneven-aged structure of the forest. All the target trees grew in the similar competitive position before selection harvesting.

Our results show that there was a delay with the diameter growth of the suppressed trees to selection harvesting, whereas the most significant growth-enhancing effect occurred three-four years after selection harvesting. In contrast to the delay in the increment, the photosynthetic rate relative to stomatal conductance increased immediately after selection harvesting, as shown by the instant 2.5‰ increase in δ13C to a post-harvest level.

Our results show that carbon uptake increased immediately for suppressed Norway spruce trees after selection harvesting, but the harvest did not induce a clear increase in stem diameter growth during the first years after the harvest.

How to cite: Lehtonen, A., Leppä, K., Rinne-Garmston, K., Sahlstedt, E., Schiestl-Aalto, P., Heikkinen, J., Young, G., Korkiakoski, M., Peltoniemi, M., Sarkkola, S., Lohila, A., and Mäkipää, R.: Fast recovery of suppressed Norway spruce trees after selection harvesting on a drained peatland forest site, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2639, https://doi.org/10.5194/egusphere-egu23-2639, 2023.

09:45–09:55
|
EGU23-5712
|
ECS
|
On-site presentation
Fahad Ali Kazmi, Mikk Espenberg, Mohit Masta, Sharvari Sunil Gadegaonkar, Sandeep Thayamkottu, Reti Ranniku, Jaan Parn, and Ülo Mander

Freezing and thawing are common phenomena and potential sources of N2O emissions in ecosystems at high latitudes. Earlier it was hypothesized that the frozen soil layer might trap the underlying production of N2O and release this as the top layer is thawed. However, newer research has found other factors playing role in the de novo emissions such as fluctuating availability of organic matter, nitrates, and ammonia, microbial activity, and changing oxic conditions of the soil. But, the variation in the abundance of genes involved in the nitrogen cycle during these events is rarely explained thus, a generally accepted theory of the impact of freeze-thaw on N2O fluxes is still missing.
To further investigate the relationships between physical, chemical, and microbial parameters with N2O emissions, we conducted a two-week experiment of three thaw-freeze events in March 2022 using artificial heating with electrical cables installed in collars of greenhouse gas sampling chambers conducted in a drained Downy birch peatland forest. Gas and soil samples were obtained on three non-consecutive days from these collars. Soil temperature, soil water content (SWC), NH4-N, and NO3-N were measured in the soil. Also, the abundances of functional genes involved in the nitrification (bacterial, archaeal, and comammox (complete ammonia oxidation) amoA) and denitrification (nirS, nirK, nosZI, and nosZII) were known using qPCR.
Our results show that artificial heating induced the thawing of the frozen top layer of soil during our experiment. The increase in soil surface temperature positively correlated with the soil water content in the top layer (R=0.58, p<0.01). N2O emissions also increased with heating and correlated with SWC (R=0.38, p<0.01). Ammonia in soil decreased and was negatively associated with N2O emissions (R=−0.28, p<0.05), suggesting active nitrification as the amount of nitrates also increased during heating. The abundance of all functional genes significantly increased during the heating except for those responsible for the consumption of N2O (nosZ genes) during
denitrification. Although we found evidence of both active nitrification and denitrification, the multiple regressions between N2O emissions and the proportion of different functional genes suggest that the nirK-type denitrifiers dominated in the denitrification as well as in the overall production of the N2O (p<0.001). Meanwhile, the inactivation of N2O consumers (nosZ) at thawing temperatures resulted in the emission of N2O during the thawing events in the drained peatland’s nitrogen-rich soil.

How to cite: Kazmi, F. A., Espenberg, M., Masta, M., Gadegaonkar, S. S., Thayamkottu, S., Ranniku, R., Parn, J., and Mander, Ü.: Impact of soil moisture changes on nitrogen cycle microbiome during the experiment of thaw-freeze cycle in a drained peatland forest, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5712, https://doi.org/10.5194/egusphere-egu23-5712, 2023.

09:55–10:05
|
EGU23-1382
|
On-site presentation
Tuula Larmola, Antti J. Rissanen, Paavo Ojanen, Leena Stenberg, Lukas Kohl, and Raisa Mäkipää

In drained peatland forests, drainage ditches cover ca. 3% of the area, but contribute to up to 100% of methane (CH4) emission. The drained peat soils, in contrast, can act as a CH4 sink especially under efficient drainage. Therefore, emissions from ditches will impact whether drained peatland is a net CH4 sink or source. The net CH4 flux is likely to be impacted by the conditions in the ditches such as the extent and type of plant cover and the time since drainage. In order to provide more accurate ditch CH4 emission factors for national greenhouse gas (GHG) inventory, we examined the fluxes and the underlying CH4 cycling processes in a nutrient rich peatland forest in Ränskälänkorpi, Southern Finland during May-October 2021. We compared the ecosystem-atmosphere CH4 fluxes and their δ13C values from moss dominated and open water ditches. We determined CH4 and CO2 mixing ratios and their δ13C values in water and in sediment by gas chromatography and cavity ring-down spectroscopy (Picarro G2201-i), respectively. We also assessed the role of CH4 as a carbon source for Sphagnum mosses growing in ditches by analyzing δ13C values in submerged and partly submerged Sphagnum using elemental analysis - isotope ratio mass spectrometry. We found that mean seasonal CH4 emissions from moss dominated ditches were 90% lower than from open water surfaces. In this dry summer, moss-dominated ditches were occasionally net sinks of atmospheric CH4. These results can be explained by CH4 consuming microbes inhabiting surface water, moss layer or sediment below the moss layer and using CH4 as a source of carbon and energy. Isotopic mass balance calculations accounting for the measured δ13C values of Sphagnum moss, dissolved CO2 and CH4 as well as fractionation against 13C during (mass-transfer-limited) moss CO2 fixation indicated that 10-28% of carbon in ditch Sphagnum mosses potentially originated from oxidized CH4. Ditch network maintenance, including removing mosses, is likely to decrease along with changing peatland forest management, e.g., continuous cover forestry. Our results suggest that ditches overgrown by mosses have potential to reduce CH4 emissions from drained peatland forests and could serve as an additional GHG mitigation measure to management practices that maintain a continuous forest cover, attenuate the changes in water table level and thus reduce CH4 emissions from peat soils.

 

How to cite: Larmola, T., Rissanen, A. J., Ojanen, P., Stenberg, L., Kohl, L., and Mäkipää, R.: Mosses as biofilters for ditch methane emissions from forestry drained peatlands, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-1382, https://doi.org/10.5194/egusphere-egu23-1382, 2023.

10:05–10:15
|
EGU23-5809
|
ECS
|
On-site presentation
Lou Goodger, Naomi Gatis, Pia Benaud, Karen Anderson, and Richard Brazier

Definitions of peatlands based on peat thickness often exclude areas of shallow peat such as those found across Bodmin Moor, southwest UK.  Although thin, in areas, these peats support Sphagnum rich vegetation communities. 

We are continuously (every 30 minutes) measuring net ecosystem exchange and methane fluxes, using automated chambers, in four vegetation communities along a wetness gradient.  We hypothesis despite the thin peat, these communities are carbon sequestering, and therefore require protection and/or restoration.

These peatlands are heterogeneous on meter spatial scales, chamber measurements enable us to capture that variability and quantify the difference between the vegetation communities present.  The temporal resolution of the data gives us certainty in the carbon budgets not previously possible using survey techniques.

How to cite: Goodger, L., Gatis, N., Benaud, P., Anderson, K., and Brazier, R.: Can thin peats sequester carbon?, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5809, https://doi.org/10.5194/egusphere-egu23-5809, 2023.

Coffee break
Chairpersons: Franziska Tanneberger, Susan Page
10:45–10:50
10:50–11:00
|
EGU23-15754
|
ECS
|
On-site presentation
Michael Bekken, Norbert Pirk, Astrid Vatne, Lena Tallaksen, Sebastian Westermann, Poul Larsen, Andreas Ibrom, Klaus Steenberg Larsen, Jacqueline Knutson, and Peter Dörsch

Norway has the third greatest extent of peatlands in Europe, after Finland and Sweden. Norwegian peatlands cover nearly 30 000 km2 or 7.7 percent of Norway’s land area. However, 6500 km2 of these peatlands have been drained for forestry or agriculture and are estimated to emit approximately 6 Mton CO2 annually, accounting for 11 percent of Norway’s total carbon emissions. In 2016, the Norwegian Environment Agency and the Norwegian Directorate of Agriculture embarked on a peatland restoration plan to reduce greenhouse gas emissions and improve the ecological conditions of drained and degraded peatlands in Norway. Since then, over 100 peatland sites have been restored. However, only one of these sites is being actively monitored to determine the effect of restoration on carbon fluxes, making this site critical to understanding carbon dynamics of restored peatlands in Norway. The site, located in the Regnåsen and Hisåsen Nature Reserve (Trysil Municipality, Innlandet county) consists of two study areas that are sub-catchments of the same watershed, cover approximately 0.5 km2, and are separated by 0.5 km. Both areas were drained in the 1960s, with a network of drainage ditches totaling approximately 4000m. One of the areas was restored in 2021 by constructing 318 dams in the drainage ditches, while the other area remains drained as a control. In 2019 eddy covariance towers were installed to track vertical CO2 and CH4 fluxes on each site. In addition, DOC, DIC and water discharge measurements were taken to estimate lateral carbon transport, and soil samples were taken to estimate carbon stocks. Preliminary results indicate that COfluxes have decreased and CH4 fluxes have increased in the restored site as compared to the drained site, and that vertical carbon fluxes account for over 90% of carbon transport on both sites. This project is coordinated by the LATICE (Land-ATmosphere Interactions in Cold Environments) project at University of Oslo. The results of this study will assist the Norwegian Environment Agency in shaping the next phase of the peatland restoration work in Norway.

How to cite: Bekken, M., Pirk, N., Vatne, A., Tallaksen, L., Westermann, S., Larsen, P., Ibrom, A., Steenberg Larsen, K., Knutson, J., and Dörsch, P.: Carbon dynamics of a controlled peatland restoration experiment in Norway, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15754, https://doi.org/10.5194/egusphere-egu23-15754, 2023.

11:00–11:10
|
EGU23-5930
|
On-site presentation
Aram Kalhori, Christian Wille, Pia Gottschalk, and Torsten Sachs

Rewetting drained peatlands is recognized as a leading and effective natural climate solution to curbing greenhouse gas (GHG) emissions. However, CO2 source-to-sink transition is not necessarily detected in years immediately following rewetting and temporal dynamics in carbon budgets can be seen in rewetted systems. Here, we investigate long-term (2008 & 2013 - present) ecosystem flux measurements using the eddy covariance technique, revealing the temporal patterns of annual carbon dioxide (CO2) and methane (CH4) fluxes, in a rewetted peatland site in northeastern Germany. We show that site-level annual emissions presented in this study are only approaching the IPCC default Tier 1 emission factors (EFs) and those suggested for the German national inventory report after 13-16 years of rewetting when the optimum range of water level (close to the soil surface) is reached during the vegetation period. Overall, our results indicate that in addition to annual variation in soil temperature, vegetation development (post-rewetting successional vegetation dynamics) along with water table depth have the greatest effect on the carbon sink function. We further observe a transitional change into a new phase in the ecosystem carbon status throughout the study period that includes a source-to-sink transition of annual CO2 fluxes in 2020. The decreasing trend for CO2 fluxes is estimated at -0.37 t CO2-C ha-1 yr-1 and -44 kg CH4 ha-1 yr-1 for CH4 emissions for the period until 2021.  While we found a strong reduction in CH4 emissions in 2019 (following a severe drought), the negative trend in CH4 emissions in the years before the drought event is still statistically significant (-17 kg CH4 ha-1 yr-1). Accordingly, a considerable reduction of the 100-year annual global warming potential (GWP) and sustained-flux global warming potential (SGWP) was observed during the course of the study and potentially approaching a new steady-state phase within the last few years. In Germany, the published long-term datasets from rewetted peatlands only cover a period of ≤10 years after rewetting, thus, the duration of potential phases and development of future emissions are still unclear. This outlines the need for more long-term datasets to cover the source-to-sink transition in rewetted peatlands that also capture the impacts of likely future climate extremes. Here, we aim to establish a baseline to contribute a better understanding of the transitioning, complexity, and climate sensitivity of rewetted systems by analyzing the dynamics within the site and the inter-annual variability via their respective drivers. The introduction, monitoring, and targeted management of an ensemble of site characteristics (coverage/type of dominant vegetation, average water level along with microclimate and microtopographic conditions) is necessary in understanding the transient nature of such systems and further refine the existing static default EFs.

How to cite: Kalhori, A., Wille, C., Gottschalk, P., and Sachs, T.: Temporal phases of GHG emissions in rewetted fen sites using multiyear ecosystem carbon flux measurements, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5930, https://doi.org/10.5194/egusphere-egu23-5930, 2023.

11:10–11:20
|
EGU23-7044
|
ECS
|
On-site presentation
Rima Bou Melhem, Line Jourdain, Sébastien Gogo, Fabien Leroy, Adrien Jacotot, Benoît D'Angelo, Fatima Laggoun-Défarge, and Christophe Guimbaud

Natural peatlands represent 1/3 of the world C soils and contribute significantly to sequestration of atmospheric CO2 by assimilation and storage of non-well decomposed organic C, due to their specific predominant vegetation such as Sphagnum species. However, they are encountering anthropogenic-induced pressures that disturb their structure (implying shift of vegetation), with potential consequences on their carbon sink function. In an attempt to mitigate this effect, restoration experiments were undertaken at La Guette peatland, a hydrologically disturbed temperate Sphagnum-peatland invaded by vascular plants, which is now a carbon source. Hydrological restoration was performed by blocking drains with dams and vegetation restoration was undertaken by either i) removing first 5 cm of peat (bare plots) or ii) removing first 5 cm of peat and transferring Sphagnum mosses (Sphagnum plots). To study the effect of these experiments, CO2 and CH4 fluxes together with environmental variables and vegetation indices were monitored from 2014 to 2017 in 24 2mx2m plots. The annual carbon budget for each plot was estimated using empirical models. Preliminary results show that the hydrological restored site presented lower annual mean CO2 emissions than the undisturbed site. In addition, Sphagnum plots had the lowest annual mean CO2 emissions followed by bare peat plots then by intact plots. Hence, the results of these models provide evidence that hydrological and vegetation restorations favour the return to the C sink function of the peatland. However, there is still a need for larger-scale studies to better estimate the effect of restoration activities on peatland greenhouse carbon budgets.

How to cite: Bou Melhem, R., Jourdain, L., Gogo, S., Leroy, F., Jacotot, A., D'Angelo, B., Laggoun-Défarge, F., and Guimbaud, C.: Effect of hydrological and vegetation restorations on the C sink function of the disturbed La Guette peatland., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7044, https://doi.org/10.5194/egusphere-egu23-7044, 2023.

11:20–11:30
|
EGU23-15114
|
On-site presentation
Gerald Jurasinski, Cordula Nina Gutekunst, Susanne Liebner, Anna-Kathrina Jenner, Erwin Don Racasa, Klaus-Holger Knorr, Sara Elizabeth Anthony, Daniel Lars Pönisch, Michael Ernst Böttcher, Manon Janssen, Jens Kallmeyer, Franziska Koebsch, and Gregor Rehder

Rewetting of drained peatlands reduces the emissions of carbon dioxide (CO2) and nitrous oxide (N2O) substantially. However, elevated methane (CH4) emissions can occur, at least in the short-term. The impact of rewetting coastal peatlands with brackish water remains yet unclear, although beneficial effects such as lower CH4 emissions seem likely, due to high sulfate availability. Here, we compare pre- and post-rewetting greenhouse gas fluxes, biogeochemical parameters and the abundance of specific microbial groups in a coastal peatland at the German Baltic Sea coast that was formerly drained and used as an agricultural grassland and recently rewetted with brackish water. 

We hypothesized that flooding with brackish seawater reduces CO2 emissions despite favoring sulfate-reducers. It should also limit CH4 production and favor anaerobic methane and thus keep CH4 emissions low although aerobic methane oxidation may decrease. We measured CH4 and CO2 fluxes along a soil wetness gradient before rewetting and along a water level gradient after rewetting with brackish seawater and estimated cumulative CH4, CO2 net ecosystem exchange (NEE), and ecosystem respiration (Reco). Soil cores for biogeochemical and microbial analyses were taken at seven locations along the transect pre- and post-rewetting. We used quantitative polymerase chain reaction (qPCR) on 16S rRNA, mcrA, pmoA and dsrB genes to quantify the abundances of total prokaryotes, methanogens, aerobic methanotrophs and sulfate-reducing bacteria.

After rewetting, cumulative CH4 net fluxes and NEE increased at locations that were previously dry, while Reco halved compared to before rewetting. This correlated with the absolute abundances of specific microbial groups and the surface/pore water biogeochemistry. Under the newly created water-logged conditions, the abundances of methanogenic as well as of sulfate-reducing bacteria (SRB) increased at previously dry sampling locations, but remained constant at the former ditch location. At the same time, the abundance of the aerobic methanotroph community on previously dry locations decreased, which indicates lower aerobic methane oxidation potentials. Pore water CH4 and CO2 concentrations suggest that gas production most likely increased at the former terrestrial locations and stable carbon isotope measurements support an increase of methanogenesis in the peat at some locations. Isotopic analyses also provide some support for persistent methane oxidation either through anaerobic or aerobic taxa at one location.

Brackish water rewetting strongly modified the dominant methane-cycling processes but resulted in higher greenhouse gas emissions of both CO2 and CH4 in the first year after rewetting. As expected, CH4 emissions after rewetting were lower than in freshwater rewetted fens, while NEE was unexpectedly high. Since Reco strongly decreased, we assume that peat mineralization was successfully prevented and that ongoing CO2 emissions rather derived from strongly reduced CO2 uptake, supply of terminal electron acceptors (especially sulfate), and excess substrate availability from decaying vegetation. There is great potential for reduction of both, CH4 and CO2 emissions after the initial boost when readily available substrate is depleted. However, our study also reveals the complexity of peatland restoration and the possibility of transient effects upon rewetting, and therefore the value of undrained, pristine peatlands as well as their importance in sequestering carbon.

How to cite: Jurasinski, G., Gutekunst, C. N., Liebner, S., Jenner, A.-K., Racasa, E. D., Knorr, K.-H., Anthony, S. E., Pönisch, D. L., Böttcher, M. E., Janssen, M., Kallmeyer, J., Koebsch, F., and Rehder, G.: Changes of greenhouse gas fluxes and corresponding microbial communities upon rewetting of a coastal peatland with brackish seawater, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15114, https://doi.org/10.5194/egusphere-egu23-15114, 2023.

11:30–11:40
|
EGU23-13951
|
ECS
|
On-site presentation
Kyle Boodoo, Jonas Niese, Enys Herbst, Katharina Fischer, and Stephan Glatzel

Peatlands represent 2.5% of all agricultural land in the EU, yet they account for ~ 25% of agricultural greenhouse gas (GHG) emissions, and ~ 5% of total EU-wide GHG emissions. Several studies have shown that peatland rewetting can reduce, or even reverse, the net GHG emissions from previously drained peatlands. We investigated GHG emissions from 14 different European peatland sites (Germany [6], Poland [4] and Netherlands [4]) across a landuse (3 levels) and water table (2 levels) gradient during a 2 year period (July 2021 – June 2023). GHG flux measurements utilizing closed, non-flow-through, dark, non-steady-state chambers were implemented to estimate ecosystem respiration from the study sites. Ecosystem respiration represents the largest share of carbon export to the atmosphere from terrestrial ecosystems. Within the study, landuse gradient was represented by the level of paludiculture (harvest frequency/ soil nitrogen levels), and water table level indicated by Typha- and Carex- dominated vegetation. Initial study results indicate that overall, CO2 fluxes varied across seasons (ANOVA, p<0.001, n = 1738, F = 14.08), with the highest fluxes occurring in summer (0.402 ± 0.342 g CO2 m-2h-1), and lowest in winter (0.233 ± 0.368 g CO2 m-2h-1). Similarly, CH4 fluxes varied seasonally, with the highest CH4 fluxes in summer (6.95 ± 8.07 mg CH4 m-2h-1) and lowest in winter (1.98 ± 4.07 mg CH4 m-2h-1). Average CO2 fluxes decreased with the increasing level of paludiculture intensity for both Typha and Carex dominated sites, while CH4 fluxes typically increased with increasing harvest frequency/ soil nitrogen levels. While CO2 and CH4 fluxes were generally higher in the early morning (as compared to afternoons), particularly during summer and autumn, we could not show an overall significant diurnal difference in GHG fluxes. Seasonal variability in CO2 and CH4 was likely an indicator of the effect of temperature and water table level on GHG fluxes. GHG fluxes at the Typha dominated sites were consistently higher than those of complimentary Carex dominated sites for each landuse class, highlighting the importance of water table and vegetation species on GHG emissions. This research was conducted as part of the Peatland Rewetting In Nitrogen-Contaminated Environments: Synergies and trade-offs between biodiversity, climate, water quality & Society (PRINCESS) project, investigating rewetting of drained, nitrogen contaminated peatlands and their potential role in reducing EU-wide greenhouse gas emissions and improving wetland biodiversity.

How to cite: Boodoo, K., Niese, J., Herbst, E., Fischer, K., and Glatzel, S.: Seasonal and diurnal patterns in Greenhouse Gas fluxes from re-wetted European peatlands, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13951, https://doi.org/10.5194/egusphere-egu23-13951, 2023.

11:40–11:50
|
EGU23-2244
|
ECS
|
On-site presentation
Miriam Groß-Schmölders and Jens Leifeld

Peatlands are a vast and vulnerable carbon stock. Although they cover only 3% of the land area, globally the organic matter stored in peat accounts for 20% of soil carbon. In peat-rich countries, peat soils contribute much to the carbon dioxide (CO2) emissions from croplands and grasslands in the national greenhouse gas (GHG) budgets. This may seriously diminish any possible net carbon sink of the land use sector. Owing to their high emission reduction potential per area, cultivated peat soils are often considered as a very effective target for GHG mitigation measures in the agriculture and land use sector. This goal can be achieved by rewetting. Rewetting often comes with synergies such as water protection, as peat soils are also high sources of dissolved organic matter and nutrient efflux. In wet soil transformation is driven by anaerobic processes and the resulting methane emissions can be considered a tradeoff of CO2 savings by wet management. How groundwater table raise influences GHG emissions depends e.g. on peat properties, environmental conditions and site management. The goal of the EU project EJP Soil INSURE, to which our research project belongs, is to evaluate the significance of different factors regulating the GHG balance of wet cultivated peat soils at different European sites and to seek for indicators of successful GHG mitigation. We contribute to this goal by analyzing the organic matter of peat profiles. We study the molecular composition of the different peats using analytical pyrolysis GC-MS, in conjunction with organic matter stoichiometry. Our aim is to better understand the role of peat properties for the biogeochemical cycles in rewetted peatlands and their GHG balance. By using different classes of compounds, we were able to distinguish between transformed organic matter and peat that is relatively rich in undecomposed plant material. We identified marker compounds that were highly specific for fresh plants, transformed plant material or microbial abundance. For example, the abundance of undecomposed plants can be linked to levosugars, decomposed plant material is pictured by low weight polysaccharides such as 5-methyl-2-furalaldehyde and microbial matter is displayed by specific nitrogen compounds, as pyridines, pyrroles and indene’s, such as 1H-indene, 3-methyl. In addition, we studied the correlation between peat stoichiometry, compound abundance and the degree of transformation. We find that for example a high C/N ratio is negatively correlated with a high amount of low weight polysaccharides and compounds indicative for microbial abundance. We conclude that our method gives a detailed insight of peat composition. Further, it enhances our knowledge of peat quality and could therefore help to gain insights into the dependency of GHG emissions on peat quality.

How to cite: Groß-Schmölders, M. and Leifeld, J.: Analyzing the degree of organic matter transformation of rewetted European peatlands in the context of their greenhouse gas emission potential, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2244, https://doi.org/10.5194/egusphere-egu23-2244, 2023.

11:50–12:00
|
EGU23-15213
|
ECS
|
Virtual presentation
Jacob Smeds, Mats Nilsson, Ulf Skyllberg, Erik Björn, Stefan Bertilsson, Kevin Bishop, and Mats Öquist

The major objective behind peatland restoration is to improve ecosystem services, such as increased biodiversity, increased carbon sequestration, increased groundwater storage, and improved surface water quality. However, a century or more of drained conditions has drastically changed the soil properties in relation to natural wetlands and this is likely to profoundly influence the potential for various biogeochemical peat processes. Thus, peatland restoration may result in undesired impacts and potential environmental threats. Two such undesired effects are increased methane production and increased mercury methylation.

In this study, we investigated how nine boreal peatlands across a latitudinal gradient in Sweden have been affected by rewetting after up to a century of drained conditions. Each peatland was sampled for three 50 cm deep peat cores that were analyzed for carbon, nitrogen, δ13C, δ15N, bulk density, and organic matter proportion. Adjacent to each restored peatland, we sampled a corresponding pristine (natural) peatland to facilitate a comparison of how the peat properties have been affected by drainage and subsequent rewetting of the peatlands. Groundwater depth was monitored at all peatland locations to confirm restored conditions at the rewetted peatlands.

The results indicate that a long period of drained conditions and subsequent rewetting have changed the peat properties, with differences shown in C/N ratio, dry bulk density, and organic matter content. Rewetting will thus not regenerate a pristine environment. Instead, it creates new conditions to which various biogeochemical processes will respond and these do not necessarily represent conditions prior to disturbance. Our study will provide background information to understand the biogeochemical dynamics in peatlands after restoration, especially since the study covers a large span of nutrient conditions and catchment settings. This understanding will be fundamental for the development of strategies to minimize undesired biogeochemical responses following peatland restoration.

 

Presentation preference: Oral, virtually

Billing address:

SLU Fakturamottagning

Box 7090

750 07 Uppsala

Referens: 241MOT 

 

How to cite: Smeds, J., Nilsson, M., Skyllberg, U., Björn, E., Bertilsson, S., Bishop, K., and Öquist, M.: Biogeochemistry and Peat Properties of Restored Wetlands, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15213, https://doi.org/10.5194/egusphere-egu23-15213, 2023.

12:00–12:10
|
EGU23-5553
|
ECS
|
On-site presentation
Jonathan Ritson, Rebecca Self, Chris Evans, and Martin Evans

In the new demonstrator project, Greenhouse Gas Removals – Peat, we aim to improve the greenhouse gas balance of peatland restoration projects so that net-negative carbon projects can be achieved. To do this, we are trialling a suite of methods including gully blocking, Sphagnum planting, biomass harvesting coupled with biochar production, and methane suppression via gypsum dosing. Through these methods, we hope to increase the input of recalcitrant carbon whilst minimising methane emissions.

We present the results of a survey of 17 peatland pools across four sites in the south Pennines, UK. The pools were created via different restoration methods and have either been colonised naturally by Sphagnum or have been planted with commercially available mixes. Our data show that floating Sphagnum mats create a poorly mixed zone in the restoration pools where temperature and dissolved oxygen levels are elevated, resulting in lower dissolved methane concentrations beneath the Sphagnum mats compared to the rest of the pool. When accounting for higher methane emission rates due to the elevated temperature, our results suggest an overall ~40% lowering of diffusive methane flux in areas colonised by Sphagnum.

Modelling of water quality parameters from the pools suggest methane flux is controlled via different mechanisms in the two areas of the pools. In the clearwater areas, redox potential and nitrogen availability are the dominant controls on methane flux, whereas under Sphagnum, dissolved oxygen concentration was the only significant driver. We interpret this as a switch in relative activity between methanogens and methanotrophs in the two areas. Taken together, our results provide real world evidence of the role of Sphagnum in creating a habitat niche favourable for methanotrophs and thereby lowering methane flux from peatland restoration projects.

In this presentation we will also discuss preliminary findings from the other treatments being trialled at our sites.

How to cite: Ritson, J., Self, R., Evans, C., and Evans, M.: Floating Sphagnum moss mats as a tool to lower methane emissions in restored peatlands, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5553, https://doi.org/10.5194/egusphere-egu23-5553, 2023.

12:10–12:20
|
EGU23-12066
|
ECS
|
On-site presentation
Annick van der Laan, Jerry van Dijk, Karin Rebel, and Martin Wassen

Peatlands are valuable ecosystems that hold a high biodiversity and provide many ecosystem services such as carbon sequestration, water storage and water purification. However, a large part of the peatlands are drained, often for agricultural purposes, resulting in CO2 emissions, soil subsidence and biodiversity loss. To combat these negative effects, various rewetting measures are being installed which can be combined with varying land-uses such as intensive dairy farming, extensive agriculture, semi-natural grasslands, paludiculture (farming on moist/wet soils) and nature restoration. This broad applicability implies that the extent by which the groundwater level is raised can be fine-tuned to the intended land use. In our study, we conducted a mesocosm experiment in which we exposed intact fen peat cores (80cm, 20cm Ø) to five different water levels (0, 20, 40, 60 cm and variable - surface), two nutrient application levels and two water qualities. For an eight-month period, monthly samples from each peat core were taken at two depths and chemically analyzed. Further, the vegetation in the cores was cut five times throughout the growing season. Above-ground biomass was measured as well as nutrient concentrations in the vegetation. Our results show increased phosphate and ammonium availability upon fully rewetting (0 cm – surface), in contrast to partially rewetted circumstances (20cm – surface) where nutrient availability was lowest. Above-ground biomass was strongly affected by nutrient application and, except for early spring growth, less by water levels. Nitrogen concentrations in the vegetation decreased with increasing water levels indicating stronger nitrogen limitation. This is likely the result of increased denitrification rates under wet circumstances. We conclude that in order to achieve nature restoration under fully rewetted conditions, additional steps must be taken to remove nutrients, particularly phosphorus, from the system. Further, we conclude that partial rewetting can be a solution to slow down the adverse effects of drainage, although agricultural production will decrease. 

How to cite: van der Laan, A., van Dijk, J., Rebel, K., and Wassen, M.: Nutrient dynamics in fen peat in relation to water level management: a mesocosm experiment, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12066, https://doi.org/10.5194/egusphere-egu23-12066, 2023.

12:20–12:30
|
EGU23-17384
|
ECS
|
Virtual presentation
Gwendal Breton, Mélina Guêné-Nanchen, and Line Rochefort

Canada is a leading producer, and exporter of peat used for horticultural purposes. Nevertheless, in that context, peat extraction requires the removal of vegetation and the drainage of Sphagnum-dominated peatlands causing disturbances of hydrological regimes and the disappearance of biodiversity as well as most ecosystems services. Moreover, when peat extraction is over, the formerly extracted peatlands become a source of greenhouse gases due to the oxidation of residual peat. Without human intervention, horticultural post-extracted peatlands will almost never return to their original pre-disturbance state. In order to solve this ecological problem, the Peatland Ecology Research Group (PERG) developed in the late 1990s an active ecological restoration method better known as the Moss Layer Transfer Technique (MLTT). Thus, the MLTT allows not only to restore the specific hydrology, but also to restore the Sphagnum carpet as well as typical peatland vegetation communities. Given the effectiveness of the MLTT to restore Sphagnum-dominated peatlands in a short period of time, it is now necessary to clarify and define the notion of a successful peatland restoration work. To achieve this, the present research project uses a fundamental tool of the science of ecological restoration embodied by the reference ecosystem. Consequently, the use of a reference set perform by natural peatlands makes it possible, through the intermediary of the vegetation communities, to appreciate the similarity or the ecological distance of the restored peatlands according to the time up since the restoration. This research work thus underlines the capacity of the MLTT to restore functional peatlands ecosystems on the basis of certain foundations taught by ecological restoration in the context of global climate change and erosion of biodiversity.

How to cite: Breton, G., Guêné-Nanchen, M., and Rochefort, L.: Ecological restoration of post-extracted peatland in Canada. A comparative approach of the vegetation community between restored and natural peatland, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17384, https://doi.org/10.5194/egusphere-egu23-17384, 2023.

Lunch break
Chairpersons: Bärbel Tiemeyer, Susan Page
14:00–14:05
14:05–14:15
|
EGU23-11048
|
On-site presentation
Jürgen Kreyling and Franziska Tanneberger

Draining temperate fen peatlands created multiple problems such as greenhouse gas emissions, eutrophication and subsidence due to peat mineralization, but also loss of highly specialized biodiversity. Based on recent own publications and (not yet published) studies, we here explore the potential of paludiculture, i.e. the wet use of peatlands, in tackling the multiple challenges mentioned above. Rewetting effectively curbs carbon losses (Tanneberger et al. 2020, 2021), but rewetted fens are more enriched in nutrients and differ in vegetation composition compared to natural fens (Kreyling et al. 2021). Brown mosses, for instance, are outcompeted by tall helophytes (Jaszczuk et al. 2022). Harvesting aboveground plant biomass can effectively reduce nutrient loads (Hinzke et al. 2021a), while belowground production leading to peat formation is even enhanced by high nutrient loads (Hinzke 2021b). Paludiculture with productive species such as Typha, however, is possible even with low nutrient availability (Haldan et al. 2022). If productive species such as Phragmites are actively introduced for paludiculture, genotypes should carefully be selected as they differ strongly in performance (Haldan et al. unpublished). Paludiculture has the potential to foster conservation targets across multiple taxa such as plants, arthropods, and birds (Martens et al. unpublished). Drought events occur with increasing intensity and frequency idue to climate change. High decomposition under these circumstances, however, is balanced by increased root production (Schwieger et al. 2020) due to an elongated belowground growing season (Schwieger et al. 2022). We conclude that paludiculture is a viable management option for rewetted fens that can curb multiple environmental challenges such as greenhouse gas emissions, eutrophication and biodiversity loss.

 

Haldan K, et al. (2022) Typha for paludiculture—Suitable water table and nutrient conditions for potential biomass utilization explored in mesocosm gradient experiments. Ecology and Evolution 12: e9191. https://doi.org/10.1002/ece3.9191

Hinzke T, et al. (2021a) Can nutrient uptake by Carex counteract eutrophication in fen peatlands? Science of the Total Environment 785: 147276.

Hinzke T, et al. (2021) Potentially peat-forming biomass of fen sedges increases with increasing nutrient levels. Functional Ecology 35, 1579-1595. I

Jaszczuk I, et al. (2022) Physiological responses of fen mosses along a nitrogen gradient point to competition restricting their fundamental niches. Oikos DOI: 10.1111/oik.09336

Kreyling J, et al. (2021) Rewetting does not return drained fen peatlands to their old selves. Nature Communications 12: 5693.

Schwieger S, et al. (2020) Wetter is better: rewetting of minerotrophic peatlands increases plant production and moves them towards carbon sinks in a dry year. Ecosystems 24: 1093–1109.

Schwieger S, et al. (2022) Rewetting prolongs belowground growing season in minerotrophic peatlands and mitigates negative drought effects. Journal of Applied Ecology DOI 10.1111/1365-2664.14222.

Tanneberger F., et al. (2020) The power of nature-based solutions: how peatlands can help us to achieve key EU sustainability objectives. Advanced Sustainable Systems 20000146, DOI 10.1002/adsu.202000146

Tanneberger F., et al. (2021) Towards net zero CO2 in 2050: An emission reduction pathway for organic soils in Germany. Mires and Peat 27, Article 05, doi: 10.19189/MaP.2020.SNPG.StA.1951.

How to cite: Kreyling, J. and Tanneberger, F.: Paludiculture in temperate fens to combat eutrophication, biodiversity loss, and climate change, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11048, https://doi.org/10.5194/egusphere-egu23-11048, 2023.

14:15–14:25
|
EGU23-14397
|
ECS
|
Virtual presentation
Carla Bockermann, Tim Eickenscheidt, and Matthias Drösler

The concept of paludicultures is growing in importance as a promising climate mitigation measure and a sustainable alternative to current agricultural use of organic soils. Besides agricultural and economic viability, quantifying the climatic effects of paludicultures is essential to give reliable policy advice and facilitate sustainable management decisions with regard to climate change. Emission factors (EFs) of the relevant greenhouse gases (GHG) carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) for a variety of potential paludiculture plants are still rare, especially from comparable treatments and site conditions.

Five different temperate fen plant species (Carex acutiformis, Phragmites australis, Phalaris arundinacea, Typha latifolia and T. angustifolia) were established as paludicultures with one or two-cut harvest frequencies at three former grassland or arable sites on fen peatland in southern Germany. Ground water levels (gwl) were manipulated to generate a water table gradient spanning annual mean gwl between +4 to −22 cm to derive an optimum gwl for GHG mitigation. One to five years after plant establishment, we measured fluxes of CO2, CH4 and N2O to obtain annual budgets (n=81 / 43 rewetted: gwl +4 to −10 cm, 38 moderately rewetted: gwl −11 to −22 cm) using manual and automatic closed chambers. Besides gas flux measurements, we observed vegetation growth parameters (LAI, NDVI) and biomass yield from harvests. The resulting mean global warming potentials are −13.0 ± 13.9 t CO2-eq ha−1 yr−1 under rewetted conditions (annual mean gwl ≥ −10 cm) and −1.0 ± 9.8 t CO2-eq ha−1 yr−1 under moderately rewetted conditions (annual mean gwl < −10 cm). Our dataset revealed that a maximum mitigation potential of paludicultures is achieved at a gwl of −7 cm. These values represent the first EFs of paludicultures for potential integration into the German national GHG inventory.

How to cite: Bockermann, C., Eickenscheidt, T., and Drösler, M.: Greenhouse gas emissions and global warming potentials of five paludiculture plants in fen peatlands in southern Germany, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14397, https://doi.org/10.5194/egusphere-egu23-14397, 2023.

14:25–14:35
|
EGU23-15534
|
On-site presentation
Merit van den Berg, Renske Vroom, Thomas Gremmen, Jacobus van Huissteden, Jim Boonman, and Bas van de Riet

With the increasing demand to reduce greenhouse gas (GHG) emissions to meet the climate goals, rewetting of peatlands has gained attention as a promising measure. To reduce or stop peat oxidation, peat should be brought in anoxic conditions again by elevating the groundwater table. With this action, land becomes less suitable for traditional agriculture. Paludiculture would be a form in which wetland plants are grown and biomass is commercially used.
In a field experiment, we studied the effect on GHG emissions from three different paludiculture species: Typha latifolia, Typha angustifolia and Azolla filiculoides. In this presentation we will focus on the following research questions: 1) Can CO2 emission reduction compensate increased CH4 emission when peatland is rewetted for paludiculture purposes? 2) What is contribution of ebullition and diffusive fluxes to the total CH4 flux of the different crop types? 3) What is the contribution of CO2 and CH4 to the total GHG balance with different crop types?

From our results we show that all paludiculture crops reduce GHG emission compared to a drained peat meadow, with highest reduction for Azolla and lowest for Typha latifolia. CH4 emission in CO2-eq is as high or higher than the CO2 emission from drained peatland, but is compensated by net CO2 uptake. Typha roots in the sediment (resulting in plant mediated gas transport), which leads to lower contribution of ebullition to the total CH4 flux. Azolla had the highest ebullition rate, but has nevertheless the lowest total CH4 emission. Most probably because Azolla is a floating plant without roots in the soil. This means that less easily degradable carbon is brought into the soil by e.g. root exudates, and that there is also no CH4 transport through the plants.

How to cite: van den Berg, M., Vroom, R., Gremmen, T., van Huissteden, J., Boonman, J., and van de Riet, B.: Comparing greenhouse gas balances from three paludiculture crops after rewetting peat: Typha latifolia, Typha angustifolia and Azolla filiculoides, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15534, https://doi.org/10.5194/egusphere-egu23-15534, 2023.

14:35–14:45
|
EGU23-13705
|
ECS
|
On-site presentation
Christina Hellmann, Bernd Bobertz, Fabian Hübner, Nora Köhn, Jürgen Kreyling, and Sebastian van der Linden

Peatlands, drained for agriculture and peat extraction, are carbon sources contributing 5% to global greenhouse gas emissions. In order to combat climate change and to meet carbon neutrality, peatlands need to be rewetted right away. Sustainable land-use alternatives such as paludiculture are needed for these rewetted sites. Paludiculture enables the production of biomass on rewetted peatlands while lowering emissions and further enhancing ecosystem services. Still, the applicability of paludiculture needs to be investigated in pilot schemes. To track the effectiveness of rewetting and crop growth, monitoring concepts are required. Data from Unmanned Aerial Systems (UAS) can help in predicting biomass by contributing information on spatial patterns of crop growth while keeping the workload of harvesting samples realistic. Here, the ability of optical UAS systems to provide both, spectral and structural information appears especially promising.

On a test site of 8 ha in Mecklenburg-Western Pomerania, Germany, a pilot scheme was established in 2019 (Paludi-PRIMA project) using Typha latifolia and T. angustifolia as target species. We monitored biomass production of Typha sp. using multispectral imagery (Blue, Green, Red, Red Edge, Near Infrared) and a Digital Surface Model (DSM), obtained from the UAS data with structure for motion.

We predicted Typha biomass for three different months (Jul, Aug, Sep), to evaluate the influence of phenology on prediction accuracy. In order to make best use of the different data properties, we combined a Typha mask from the multispectral imagery from all three dates (Random Forest classification with 82.5% overall accuracy and above) with structural information from the DSM.

Biomass was predicted by regression models using training data from in-situ harvests of Typha in 1-m2 square plots. For these plots, spatial metrics were derived for selected UAS data derivates, e.g. the median of vegetation height from the DSM or of the NDVI. The resulting regression models were then applied to rasters representing the same metrics for the full study area. Results were validated using R2, RMSE and MAE and reference information that was independently predicted from field measurements (height and shoots) for the respective observation dates.

Biomass prediction worked best with the DSM max throughout the months, with highest accuracies in August (R2=0.68 and above, RMSE<150 g/m2). The application of the Typha mask improved results for all regression models, not only for Typha-free but also surfaces with mixed vegetation cover.

We conclude that UAS data contributes essentially to biomass monitoring on experimental paludiculture sites. The combination of structural and spectral information, e.g. in the form of structural metrics and a spectral-based species mask, uses the advantages of UAS data. For larger areas the present findings need to be integrated with spaceborne data, e.g. hyperspectral satellites that add further information to the modelling.

How to cite: Hellmann, C., Bobertz, B., Hübner, F., Köhn, N., Kreyling, J., and van der Linden, S.: Predicting biomass production of Typha spec. on a rewetted paludiculture site over time using multitemporal and multispectral UAS data, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13705, https://doi.org/10.5194/egusphere-egu23-13705, 2023.

14:45–14:55
|
EGU23-5352
|
ECS
|
On-site presentation
Arasumani Muthusamy, Fabian Thiel, Vu Dong Pham, Christina Hellmann, and Sebastian van der Linden

Undisturbed peatlands constitute relevant carbon sinks. However, drained or degraded peatlands cause carbon emissions and more than 90 % of the peatlands in Mecklenburg-Western Pomerania, Germany, have been drained. In order to achieve the goals for climate change mitigation, several initiatives have been taken to restore drained and degraded peatlands by rewetting. Previously, drained peatlands were used for agricultural and grassland production, which led to significant carbon emissions. The Paludiculture scheme was introduced to allow sustainable and climate-friendly agricultural production under permanently wet conditions, which allow carbon sequestration of the soil. Phragmites australis (Reed) and Typha spp. (Cattail) are key plants for paludicluture in rewetted areas of north-east Germany.

It is necessary to regularly monitor the plant communities in rewetted areas, as this can be an indicator of rewetting success. Distinguishing peatland vegetation communities require high spectral resolution images, whereas multispectral images may show comparable spectral signatures in different peatland vegetation types. Recently launched hyperspectral sensors offer new possibilities regarding accurate vegetation monitoring in rewetted peatlands. In this study, we investigated multi-date hyperspectral images from DESIS, mounted on the International Space Station (ISS), and satellite-based PRISMA for peatland vegetation mapping. In addition to the increased spectral information, both sensors allow multiple observations per year, which was not the case for airborne hyperspectral data. The 30-m spatial resolution of both sensors, however, brings along multiple peatland vegetation communities within single pixels; hence we used a sub-pixel classification strategy using a Regression-based unmixing approach with synthetic training data. Our analyses focussed on the influence on map accuracy by i) the hyperspectral information and ii) the observation dates. 

We observed that combining April and June PRISMA (MAE = 16.4%) and April and June DESIS (MAE = 17.3%) datasets produced the best results for mapping the peatland vegetation fractions. Analysis of single dates showed that June data leads to slightly better results than April. We found that PRISMA images produced slightly better results than DESIS, which may be caused by the shortwave infrared information missing in the DESIS data. In contrast, DESIS has only visible and near-infrared bands (400-1000 nm) despite having a higher spectral resolution (2.55 nm) than PRISMA (10 nm). 

In conclusion, the hyperspectral information, especially from the short wave infrared > 1 µm, together with the multi-date observation could be shown to contribute to sub-pixel mapping accuracy. In the future, PRISMA and DESIS images can be coupled with EnMAP and the forthcoming SBG and CHIME missions to further improve the space-borne monitoring of rewetted peatlands.

How to cite: Muthusamy, A., Thiel, F., Pham, V. D., Hellmann, C., and van der Linden, S.: Mapping vegetation cover on rewetted fen peatlands using hyperspectral spaceborne images from DESIS and PRISMA, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5352, https://doi.org/10.5194/egusphere-egu23-5352, 2023.

14:55–15:05
|
EGU23-12916
|
On-site presentation
Alexander Buzacott, Merit van den Berg, Bart Kruijt, Laurent Bataille, and Ype van der Velde

Peatlands are commonly a mosaic of vegetation types, ditches, and open water. Eddy covariance provides a useful way to measure fluxes at the ecosystem scale, however comparing fluxes and annual balances from different source areas in heterogenous field sites can be challenging. Separating fluxes based on wind direction is a commonly used approach to study different source areas, but this method may exclude a substantial amounts of data points that contain some information about flux behaviour, such as when the flux source area covers multiple land cover classes, and as a result the gapfilled timeseries contains greater uncertainty. In this presentation, we present a Bayesian approach that utilises the flux footprint to gapfill CO2 and CHfluxes. A flux footprint model was used to predict the flux source area and the relative contribution for each land cover class is calculated for each timestep. The net ecosystem exchange (NEE) of a scalar is then assumed to be the linear combination of the different land cover classes weighted by the contribution within the flux footprint. A Bayesian framework was used to estimate model parameters for gapfilling each land cover class for the NEE of CO2 and CH4, where the non-linear model approaches were used in both cases. For CO2, the framework estimated the parameters for the gross primary production (GPP) light response curve and Reco via the Lloyd-Taylor respiration function, where the NEEof CO2 was then calculated as the sum of GPP and Reco. For CH4, a non-linear temperature dependence model was used.  We show results from multiple eddy covariance towers on peatlands in the Netherlands, including a mixed paludiculture pasture site, natural vegetation sites, and a pasture site with subsurface drainage. We demonstrate that this approach is useful for constraining flux behaviour and obtaining annual balances for each land cover class within the flux footprint.

How to cite: Buzacott, A., van den Berg, M., Kruijt, B., Bataille, L., and van der Velde, Y.: A Bayesian approach to gapfilling fluxes from heterogenous Dutch peatlands measured by eddy covariance, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12916, https://doi.org/10.5194/egusphere-egu23-12916, 2023.

15:05–15:15
|
EGU23-14384
|
ECS
|
On-site presentation
Claas Voigt, Arndt Piayda, Samuli Launiainen, Maren Dubbert, Kersti Leppä, and Jan Oestmann

Undisturbed raised bogs are characterised by permanent water saturation which prevents decomposition of peat, limits the spread of vascular plants and makes the ecosystem a peat moss dominated sink of carbon. Lower water levels e.g. due to climate change or drainage endanger ecosystem functions and lead to an altered vegetation composition. In particular, encroaching vascular plant species are a growing thread to natural or restored peatlands in Central Europe. While previous work often focussed on how greenhouse gas emissions or ecosystem functions of raised bogs respond to changing environmental conditions, the impact of encroaching vascular plants is only sparsely covered. As process-based SVAT models are able to simulate different vegetation compositions and their respective water and carbon fluxes, they are an optimal tool to answer this relevant question. However, this requires the relevant processes of a vegetation shift impacting the system’s water and carbon relations to be correctly implemented.

Models capable of simulating bryophyte processes are sparse. We use the process-based SVAT model 'pyAPES' including a bryophyte layer, developed and tested for boreal peatlands, at a bog site in northern Germany. The overall objective of this study is to identify whether pyAPES is able to simulate carbon fluxes of a temperate raised bog under a changing vegetation composition. We addressed four research questions: (i) Does model parametrization need to be changed when using pyAPES for temperate conditions? (ii) How do these changes affect modelled gross primary production (GPP) and ecosystem respiration (Reco)? (iii) Which photosynthetic and respiratory parameters are most crucial for model performance? (iv) Does the order of crucial parameters depend on vegetation composition and on environmental conditions?

We answer these questions by calibrating pyAPES to measured soil temperature (Ts), water table depth (WTD), seasonal dynamics of vascular plant leaf area index (LAI) and GPP and Reco fluxes. Morris sensitivity analysis (MSA) is conducted with the calibrated model to investigate parameter impacts on modelled GPP and Reco.

Preliminary results show that pyAPES performs well for a temperate raised bog after adaptation of the model parameters. Most important parameters for calibrating pyAPES were parameters of the unimodal Van-Genuchten-Mualem water retention model for both moss and peat and Farquhar parameters, which are sparse in literature.

MSA is conducted for GPP and Reco using annual sums. Boundaries for MSA are set to ± 20% around initial parametrisation in order to derive a standardized rank of parameter importance as well as to observed boundaries from literature to cover the whole range of possible site conditions. Subsequent analysis will give evidence whether meaningful parameter inference with respect to ecosystem carbon fluxes is possible under different site conditions.

Further, we investigate the impact of changing vascular plant LAI and moss biomass due to encroachment on ecosystem carbon fluxes by applying full factorial parameter combinations inferring possible shifts in model sensitivities. In a last step, we investigate intraannual shifts of sensitivities in half-hourly resolution to assess the impact of dynamic environmental conditions like WTD and moss surface temperature.

How to cite: Voigt, C., Piayda, A., Launiainen, S., Dubbert, M., Leppä, K., and Oestmann, J.: Does vascular plant encroachment affect parameter importance for modelling carbon dioxide fluxes in temperate raised bogs?, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14384, https://doi.org/10.5194/egusphere-egu23-14384, 2023.

15:15–15:25
|
EGU23-16021
|
ECS
|
On-site presentation
Hanna Vahter, Muhammad Kamil Sardar Ali, Thomas Schindler, Andis Lazdiņš, Ain Kull, Ieva Līcīte, Ülo Mander, Aldis Butlers, Jyrki Jauhiainen, Dovile Ciuldiene, and Kaido Soosaar

Organic soils are one of the largest natural terrestrial carbon stores, especially in boreal, temperate, and tropical wet climates. In these environments, scarcity of oxygen due to soil wetness has enabled the accumulation of organic carbon deposits over the past millennia. In Europe, organic soils account for only 3% of total agricultural land. Yet, they play a significant role in meeting Europe's 2030 and 2050 climate change mitigation targets. However, drainage of these soils, as a common management practice aiming for higher agricultural productivity, transforms these carbon-rich soils into a significant GHG source.

Water-level management practices are critical in agriculture to minimize soil degradation and nutrient leaching. Fluctuations in water levels may alter soil physical and chemical conditions and potentially cause GHG emissions. Deep draining leads to an increase in carbon dioxide (CO2) and nitrous oxide (N2O) emissions due to increased soil mineralization. On the other hand, methane (CH4) emissions are lower compared to natural wetlands where soil drainage and tillage do not occur. Land use, climate zone, soil nutrient status, fertilization, and drainage status are closely related to estimating GHG budgets from managed sites on organic soils.

Available data on actual GHG emissions from drained and nutrient-rich organic soils under different management practices show considerable variation. Therefore our study's main objectives are: (I) to update GHG emission factors for organic soils in drained croplands and grasslands and (ii) to calculate soil carbon and nitrogen budgets applicable to the Baltic countries. A two-year study was conducted from January 2021 to December 2022 to assess the impact of drainage and land use on GHG fluxes in the Baltic countries.

Fluxes in croplands and perennial grassland on nutrient-rich organic soils with different drainage conditions were determined by groups: (I) excessively drained croplands, (II) excessively drained grasslands, (III) moderately drained grasslands, (IV) rewetted grasslands, and (V) non-managed fens as reference sites. Measurements were done monthly (Latvia and Lithuania) or twice per month (Estonia) using the manual static dark chamber method (N2O, CH4), the dynamic transparent chamber method for net ecosystem exchange, and the dynamic dark chamber for soil heterotrophic respiration (CO2). In addition, we measured associated environmental parameters (water table level, soil moisture and temperature, and solar radiation). For biomass analyses, we took samples once in the measurement period.

Our preliminary results show that all grasslands were annual CH4 sinks, while fens soils in natural status were a source of CH4. All studied sites were N2O sources on an annual basis, and croplands were the strongest emitters, as was expected. Higher N2O emissions and temporal variability were associated with sites characterized by high groundwater levels with high seasonal fluctuations. Soil heterotrophic respiration fluxes peaked over all the study sites during the summer. As the last field campaign shortly ended, more detailed data analyses will be presented at the conference.

This research was supported by the LIFE programme project "Demonstration of climate change mitigation potential of nutrients rich organic soils in Baltic States and Finland", (2019-2023, LIFE OrgBalt, LIFE18 274CCM/LV/001158).

How to cite: Vahter, H., Sardar Ali, M. K., Schindler, T., Lazdiņš, A., Kull, A., Līcīte, I., Mander, Ü., Butlers, A., Jauhiainen, J., Ciuldiene, D., and Soosaar, K.: Drainage Impact on Greenhouse Gas Emissions from Grasslands and Croplands on Nutrient-rich Organic Soils in Baltic Countries, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16021, https://doi.org/10.5194/egusphere-egu23-16021, 2023.

15:25–15:35
|
EGU23-13830
|
ECS
|
On-site presentation
Yuqiao Wang, Sonja Paul, Christine Alewell, and Jens Leifeld

Drainage for agriculture induces peatland decomposition, subsidence, and nitrogen (N) losess, thereby contributing to climate change. In order to maintain the productivity of agricultural managed peatland, and to counteract soil subsidence, mineral soil coverage is becoming an increasingly used practice in Switzerland and other European countries. Mineral soil coverage may change the N balance from the corronsponding organic soil. To explore the effect of this practice on the N flow within the plant – soil system and the N loss, we carried out a field experiment on a peatland in the Swiss Rhine Valley that was managed as an intensive meadow. The peatland was divided into two parts, either without (Ref) or with mineral soil coverage, thickness ~ 40 cm (Cov). In this experiment, 15NH415NO3 were applied on field plots to follow the recovery of 15N in grass, root, and soil over 11 months. The 15N that was not recovered was designated as lost via leaching or gaseous emissions. Soil N mineralization was measured in a laboratory incubation. And the gaseous N loss as N2O was determined by automatic time integrating chamber systems (ATIC) over two years. The experimental results showed that the total 15N loss from Cov was lower (p < 0.05) than from Ref, even though plant 15N uptake did not vary between the two sites. The lower net N loss from the Cov site was accompanied by higher soil 15N retention in the soil. The laboratory incubation revealed a ~2 times higher specific N release per unit soil N at Cov than at Ref, suggesting a faster SOM turnover rate at Cov. Regarding the N loss as N2O, emissions from Ref were at the upper end of previously measured fluxes in drained peatland. In contrast, N2O emissions from Cov were reduced by a factor of nine over two years. Overall, the mineral soil cover increased the retention of fertilizer-N in the soil, thus reducing the system N losses, especially N loss as N2O emissions. Our results indicate agricultural production on drained peatland is less harmful to the environment with mineral soil coverage than using drained peatland directly. 

How to cite: Wang, Y., Paul, S., Alewell, C., and Leifeld, J.: Nitrogen losses from drained temperate agricultural peatland after mineral soil coverage, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13830, https://doi.org/10.5194/egusphere-egu23-13830, 2023.

15:35–15:45
|
EGU23-13555
|
ECS
|
Virtual presentation
Emily Fearns-Nicol, Fred Worrall, and julia Knapp

Although peatlands are a great store of terrestrial carbon they are only a small sink compared to other nature-based or technological approaches to carbon sequestration. So as to exploit the considerable carbon storage potential of peatlands is it possible to enhance the magnitude of the peatland carbon sink with additional inputs of carbon? Biochar is refractory form of carbon that can be sourced from natural woody materials including biomass that may grow on peatlands. Biochar’s refractory nature means that it has commonly been proposed for nature-based carbon storage. The advantage of using biochar on peatlands is that natural accumulation of peat means that the growth of peat may absorb the added biochar where on mineral soils biochar may come to dominate with repeated additions of char. However, the fate and impact of biochar on the natural function of peat soils is not known – this study has aimed to fill this knowledge gap and assess whether biochar could be applied to peatlands?

This study has conducted a random-block design based upon two different application rates of biochar to a former lowland raised bog in Yorkshire. The trial consisted of triplicated plots considered within the water table frame of the peatland and plots visited at least monthly for more than a year. The plots were monitored for: gross primary productivity; net CO2 exchange; ecosystem respiration; soil water quality; albedo; and vegetation coverage alongside measurement of water table depth and weather parameters.

The study shows:

  • that although biochar is alkali, and that there was an initial difference in pH due to biochar treatment, this difference did not last;
  • the soil water conductivity was dominated by changes in depth to water table and not biochar treatment;
  • after 10 months the DOC in soil water on treated plots was significantly higher on biochar treated plots;
  • vegetation had recovered from biochar treatment within 6 months; and
  • there was no significant difference in NER between treatments showing no ready decomposition of the biochar.

The limitations of biochar to enhance carbon storage in peatlands are more likely to be economic than biogeochemical.

How to cite: Fearns-Nicol, E., Worrall, F., and Knapp, J.: Use of biochar to enhance carbon sequestration in peatlands, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13555, https://doi.org/10.5194/egusphere-egu23-13555, 2023.

Posters on site: Tue, 25 Apr, 08:30–10:15 | Hall A

Chairpersons: Franziska Tanneberger, Bärbel Tiemeyer, Susan Page
A.286
|
EGU23-11939
|
ECS
Patryk Poczta, Kamila Harenda, Mariusz Lamentowicz, and Bogdan Chojnicki

Peatlands are ecosystems with relatively low net productivity but a long-term carbon storage period (thousands of years). This carbon stock is continuously related to its hydrogenic origin, resulting in the high sensitivity of peatlands to hygrothermal factors such as temperature and precipitation. Changing the balance of temperature and wetness in peatlands may stimulate higher ecosystem respiration and/or reduce the photosynthetic capacity of plants and consequently shift the peatland from net sinks to sources of CO2 to the atmosphere. Thus, the peatland-climate interaction study is crucial for understanding and predicting their faith in the future.

Since July 2019, the eddy covariance (EC) technique has been used to monitor CO2/H2O net fluxes at a baltic raised bog in Bagno Kusowo Nature Reserve, northern Poland (53.82 N, 16.59 E, 144 m a.s.l.). This peatland started formatting thousands of years ago and currently reaches up to 8 m of peat depth. The measurement tower works in collocation with the meteorological station, thus the standard meteorological parameters are measured along with flux observations. These common measurements were the basis for estimating peatland carbon dioxide balance and its relation to biophysical factors.

An early start of vegetation (March-April) on the baltic raised bog was noted, as well as predominant emissions from the peatland in mid-summer (August). During 2.5 years of measurements, the peatland in Kusowo was both a net sink and a source of CO2 on an annual basis. The negative impact of lowering the water table level on the CO2 balance (higher emissions) is more noticeable during the growing season when higher temperatures intensify the respiration processes.

How to cite: Poczta, P., Harenda, K., Lamentowicz, M., and Chojnicki, B.: Baltic raised bog carbon dioxide balance dynamics and its biophysical determinants - Kusowo case study, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11939, https://doi.org/10.5194/egusphere-egu23-11939, 2023.

A.287
|
EGU23-13134
|
ECS
|
Joosep Truupõld, Reti Ranniku, Muhammad Kamil Sardar Ali, Ülo Mander, Thomas Schindler, and Kaido Soosaar

Peat bogs are terrestrial wetland ecosystems where waterlogging prevents the complete decomposition of plant material. Therefore, organic matter production exceeds its decomposition, resulting in net peat accumulation. However, anthropogenic pressures, such as drainage for forestry, significantly affects those systems' biogeochemistry. Drainage lowers the originally high water table, increasing the oxic peat layer depth, which changes the dynamics of peat soil greenhouse gas (GHG) fluxes. Moreover, change dynamics can differ in peatland types. While GHG fluxes from drained minerotrophic and ombrotrophic peatlands are relatively well studied, drained transitional peatlands require additional accurate data for different spatio-temporal conditions.
This study aims to estimate the magnitude and temporal variability of soil GHG fluxes in three drained transitional bog forests in southeastern Estonia with different tree compositions, dominated respectively by Downy Birch (Betula pubescens), Norway Spruce (Picea abies) and Scots Pine (Pinus sylvestris), in addition to one drained raised bog forest dominated by Scots Pine. Ongoing sampling campaigns run twice a month from April 2022 to March 2023. Soil CO2 fluxes (heterotrophic soil respiration; n=6) are measured using a dark dynamic chamber connected to EGM-5 Portable CO2 Gas Analyzer. To estimate soil CO2 (forest floor respiration), N2O and CH4 fluxes, gas concentration samples are collected at 20-minute intervals during an hour-long session using manual static chambers (n=6) and are analyzed with Shimadzu GC-2014 gas chromatography. Soil environmental parameters (water table depth, soil temperature and moisture) are measured simultaneously with GHG measurements at each site.
Preliminary results (April 2022 – December 2022) show that sites with greater depth of oxic peat layer were, on average, stronger emitters of CO2 (forest floor respiration) and net CH4 sinks. The birch site had the highest average CO2 flux (103.6 ± 9.96 mg C m−2 h−1, mean ± SE), while the drained raised bog pine forest site had the lowest (59.9 ± 4.82 mg C m−2 h−1). The transitional bog sites were net CH4 sinks, with the birch site being the largest (−85.85 ± 7.41 μg C m−2 h–1), in contrast to the drained raised bog pine forest being a net source (33.92 ± 20.38 μg C m−2 h−1). The nitrogen-rich spruce site had the largest N2O emissions (27.64 ± 9.88 μg N m−2 h−1), with the highest fluxes in April and May (with a maximum of 309.84 μg N m−2 h−1). Further analysis of soil GHG fluxes and linkage to soil chemical, physical and environmental parameters will help determine and explain the magnitude and temporal variability of drained transitional bog forest's GHG fluxes and, consequently, highlight the importance of disturbance of these sensitive ecosystems.

How to cite: Truupõld, J., Ranniku, R., Sardar Ali, M. K., Mander, Ü., Schindler, T., and Soosaar, K.: Annual greenhouse gas fluxes from drained transitional bog and raised bog forest soils with different tree species composition, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13134, https://doi.org/10.5194/egusphere-egu23-13134, 2023.

A.288
|
EGU23-11812
|
ECS
|
Ahmed Shahriyer, Tiina Markkanen, Henri Kajasilta, Mika Korkiakoski, Helena Rautakoski, Yao Gao, Suvi Orttenvuouri, Istem Fer, Edwin Haas, David Kraus, Ruediger Grote, Mika Aurela, Annalea Lohila, and Tuula Aalto

Draining peatlands for forestry and agriculture has been a common practice in Nordic countries in the last century. In drained peatland forests, trees act as carbon sink, while well-aerated peat soil is a source of carbon. Traditionally in even aged forestry all the trees are removed in clear-cut harvesting, whereas the continous cover forestry, with partial removal of a stand in selection cuttings, have been suggested to serve as climate wise option for peatlands.

 

A process-based model ‘Landscape De-Nitrification De-Composition’ (LDNDC) was used to simulate fluxes of matter and energy of a drained nutrient-rich peatland forest ecosystem in southern Finland. LDNDC utilizes several sub-models for physiology, biogeochemistry, hydrology and microclimate and it simulates ecosystem water, energy and carbon balances including methane balance along with vegetation structure development. Multiple species can be simulated simultaneously as a mixed forest cohort, and contributions of the ground vegetation can be included. Different management methods of the forestry industry, e.g clear cutting or selection cutting have been simulated successfully.

 

Local meterological data from 2010-2018 was used to drive the model and this data was cycled through several times to start the simulation run from 1969. The amount of carbon storage in the soil was set according to the measurements at nutrient-rich peatlands. Three different simulation runs were made for a clear-cut or a selection cutting taking place in 2016 and a reference forest with no cutting. Pine was simulated as a dominant tree species prior to the management actions along with spruce and birch as a secondary canopy and alpine meadows as ground vegetation. Eddy covariance and chamber measurements from both management and reference sites were used to evaluate model performance.

 

The model captured the net ecosystem exchange, gross primary production, terrestrial ecosystem respiration and methane fluxes well. The model also captured the changes in soil moisture and water-table level caused by the applied forest management methods. Leaf area index (LAI) of the combined vegetation cohort represented the measured LAI quite well along with the growth of the individual species. Successful implementation of the model resulted in extension of simulations until 2100 using different climate drivers to investigate effects of future management scenarios on various ecosystem balances. These model results can be utilized to provide recommendations for peatland forest management, which can ensure reduction in forestry related emissions and improve the possibilities for the peatland forest to act as a sink of carbon.

How to cite: Shahriyer, A., Markkanen, T., Kajasilta, H., Korkiakoski, M., Rautakoski, H., Gao, Y., Orttenvuouri, S., Fer, I., Haas, E., Kraus, D., Grote, R., Aurela, M., Lohila, A., and Aalto, T.: Implementation and evaluation of Landscape-DNDC model for forestry management methods in a nutrient-rich peatland site in southern Finland., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11812, https://doi.org/10.5194/egusphere-egu23-11812, 2023.

A.289
|
EGU23-2645
|
ECS
|
Olli-Pekka Siira, Tuula Aalto, Ellinoora Ekman, Sami Haapanala, Angelika Kübert, Kari Laasasenaho, Markus Lampimäki, Risto Lauhanen, Tiina Markkanen, Hannu Marttila, Kari Minkkinen, Paavo Ojanen, Tuukka Petäjä, Lassi Päkkilä, Maarit Raivonen, Helena Rautakoski, Erkka Rinne, Harri Vasander, Markku Kulmala, and Annalea Lohila and the ACCC, RESPEAT & TURNEE Research Team

To achieve the ambitious goals for carbon neutrality, countries ought to, not only reduce the greenhouse gas emissions of the energy, industry, and traffic sectors, but also enhance the carbon sinks of the Land Use, Land Use Change, and Forestry sector (LULUCF). According to the national inventory of Finland under the Kyoto Protocol (United Nations Framework Convention on Climate Change), for the first time in 2021, the LULUCF sector seems to have turned from a net sink to a net source of greenhouse gases (GHG).

There are approximately 4.84 Mha of drained peatlands for forestry, 0.250 Mha of drained peatlands for agriculture, and 0.100 Mha of areas for industrial peat extraction purposes, in Finland. Yearly emissions from the forestry-drained peatlands are 6.0 Mt CO2-eq and from the wetlands 2.2 Mt CO2-eq.

The TURNEE project, funded by The Ministry of Agriculture and Forestry of Finland, investigates the climate impacts of afforestation of cutover peatlands and restoration of fertile peatland forests. Quantification of the total climate impacts of the LULUCF sector, accounting for GHG balances, albedo, aerosol-cloud-climate and water cycle effects, and feedback to ecosystems, is one of the scientific objectives of the Academy of Finland Flagship: Atmosphere and Climate Competence Center (ACCC). The RESPEAT project, funded by the Academy of Finland, focuses on quantifying the potential of boreal peatland rewetting for climate change mitigation including changes in local microclimates through biophysical impacts.

To study the net ecosystem exchange (NEE), we have established two new observation stations: one in 2021 on a cutover peatland at Naarasneva in central Finland; and one in 2022 on a peatland forest at Rottasniitunsuo in southern Finland, which will be rewetted in 2024. The functional idea is based on the SMEAR (Station for Measuring Earth surface – Atmosphere Relations) concept.  

At both sites, carbon dioxide as well as sensible and latent heat fluxes, are measured using the eddy covariance (EC) technique. Methane fluxes are measured utilizing in-situ chamber technique, and with EC method at the rewetted peatland. Biogenic particle formation is measured with neutral cluster and air ion spectrometer. Supporting measurements include upward and downward radiation, soil temperatures, soil heat flux, relative humidity, and air temperature. Geochemical properties and hydrological changes are monitored by extensive field sampling. The vegetation growth is monitored by fieldwork with the assistance of unmanned aerial vehicle based RGB photographing. Long-term climate impacts of peatland afforestation and peatland forest restoration are scaled and modeled using the LDNDC and JSBACH-HIMMELI land surface process models.

The ongoing research projects deliver in-situ data on peatland greenhouse gas fluxes, biogenic particle formation, and surface energy balance providing information on climate impacts of different land use measures of managed peatlands. The results could also steer and prioritize rewetting and restoration actions for maximum impact. This knowledge is crucial in tackling the climate crisis by mitigating the LULUCF sector emissions.

How to cite: Siira, O.-P., Aalto, T., Ekman, E., Haapanala, S., Kübert, A., Laasasenaho, K., Lampimäki, M., Lauhanen, R., Markkanen, T., Marttila, H., Minkkinen, K., Ojanen, P., Petäjä, T., Päkkilä, L., Raivonen, M., Rautakoski, H., Rinne, E., Vasander, H., Kulmala, M., and Lohila, A. and the ACCC, RESPEAT & TURNEE Research Team: Observations of climate impacts of cutover peatland afforestation, and peatland forest restoration, in Finland, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2645, https://doi.org/10.5194/egusphere-egu23-2645, 2023.

A.290
|
EGU23-15518
Anke Günther, Franziska Koebsch, Huth Vytas, and Gerald Jurasinski

The climate effect accomplished through peatland rewetting is primarily assessed via the global warming potential (GWP), as it evolves from the emissions of greenhouse gases CO2 and CH4. The GWP aggregates the various radiative efficiencies and atmospheric lifetimes of the involved greenhouse gases into a single metric and forms the base of existing accounting approaches to incorporate peatland-based land use measures in climate reporting under LULUCF.

Building on the work of Neubauer and Megonigal (2015) on the relevance of the continuous emission behavior of peatlands, we propose additional metrics based on the radiative forcing (RF) dynamics that occur after rewetting. These metrics, unlike GWP, are not tied to fixed reference time horizons and can add further aspects to the climate assessment of rewetting:

  • The switch over time: the time when the net RF trajectory approaches zero, which marks the turning point for the peatland to exert a net cooling effect
  • Total radiative forcing: the total heat energy released until switch over time is reached.
  • Pay-off time: the time when mitigation effects occur, i.e., a rewetting measure becomes climatically beneficial compared to ongoing drainage as business-as-usual land use scenario. The pay-off time requires emission data from the drainage state, but can also be estimated in reference to established inventory approaches such as Tiemeyer et al. (2020).

Our literature review revealed that most rewetted peatlands fall in one out of three main categories: (i) cases with instant mitigation effects that exert a net cooling effect within few decades (ii) cases where mitigation is reached within 10-20 years, but cause persistent warming, and (iii) cases in which mitigation is unlikely to be achieved.  

We want to discuss, whether the metrics introduced can be a scientifically substantiated and intuitive complement to the established GWP. We think, that our approach can further structure and facilitate the communication on the climate prospects of peatland rewetting. A systematic analysis of available literature values within the assessment framework presented can help to prioritize implementation actions and tailor future research activities.

References

Neubauer, Scott C., and J. Patrick Megonigal. "Moving beyond global warming potentials to quantify the climatic role of ecosystems." Ecosystems 18.6 (2015): 1000-1013.

Tiemeyer, Bärbel, et al. "A new methodology for organic soils in national greenhouse gas inventories: Data synthesis, derivation and application." Ecological Indicators 109 (2020): 105838.

How to cite: Günther, A., Koebsch, F., Vytas, H., and Jurasinski, G.: Hot or not – How do we want to rate the climate effects of peatland rewetting?, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15518, https://doi.org/10.5194/egusphere-egu23-15518, 2023.

A.291
|
EGU23-8941
Stephan Glatzel and Bagó Mari-Liis

Microbially mediated methanogenesis is a considerable source of methane (CH4) and has a major role in the global carbon cycle. In peatlands, acetate, CO2 and methylated compounds are precursors for CH4 and different substrates are used by different microorganisms. CH4 may be produced by a) acetate disproportionation (acetoclastic/acetotrophic methanogenesis), b) reduction of carbon dioxide by dihydrogen (hydrogenotrophic methanogenesis), and c) using methylated compounds (methylotrophic methanogenesis). As different methane sources have different carbon isotopic ratios, those signatures may be used to divide emissions from different sources, although these can vary temporally and spatially. Here, we hypothesize that CH4 production pathways from Sphagnum peat with clipped vascular vegetation (Callluna Vulgaris) significantly differs from CH4 production pathways from peat cores with vascular plant cover.

In order to test this hypothesis, six undisturbed peat mesocosms from Pürgschachen Moor were sampled to determine the CO2 and CH4 efflux and its 12C/13C signature for four weeks. Three control cores were left unclipped as control and in three cores, vascular vegetation was clipped to assess the significance of vascular vegetation to CH4 emissions. Ancillary parameters examined were dissolved organic carbon and acetate concentrations in peat pore water as well as hot water soluble carbon from peat.

CO2 fluxes ranged in clipped cores between 2.4 to 12.2 g m-2 h-1 and in control cores between 4.13 to 14.6 g m-2 h-1. CH4 fluxes ranged from 0.058 to 0.16 g m2 h-1 in the clipped cores and from 0.046 to 0.751 g m2 h-1 in the control group. For both CO2 and CH4, treatment had a significant effect on the fluxes.  δ13C for CH4 values in the experiment group (-55.6 ± 2.45‰) were in the same range as the control group, whereas after the clipping the experiment group values slightly decreased to -54.1 ± 2.65‰. For the control group, δ13C values were -55 ± 2.2‰. δ13CO2 was -11.2 ± 0.72‰ before and -10.8 ± 0.67‰ after clipping in the experiment group. In the control group, the average was -11.2 ± 0.71‰.

Taking into consideration the aforementioned results and other parameters measured throughout this study, it can be acclaimed that the presence of vascular vegetation changes the ability of the peat profile to produce and emit both CO2 and CH4. Even though no significant difference found between the control and the experiment group for δ13CH4, it can be acclaimed that in Pürgschachen Moor the hydrogenotrophic pathway is dominant, with average δ13CH4 values of -55 ± 2 ‰, although both pathways coexist.

How to cite: Glatzel, S. and Mari-Liis, B.: Methanogenic Pathways in Pürgschachen Moor, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8941, https://doi.org/10.5194/egusphere-egu23-8941, 2023.

A.292
|
EGU23-13069
|
ECS
Emilie Gios, Willem-Jan Emsens, Inge van de Putte, Ruurd van Diggelen, Erik Verbruggen, and Hanna Silvennoinen

Extensive peatland rewetting efforts have recently been proposed to restore these key terrestrial carbon storage systems in order to mitigate greenhouse gas (GHG) emissions. However, little is known about the effects of rewetting on peat microbial functions that are linked to GHG fluxes. A better understanding of which biotic and abiotic factors control these processes in rewetted peatlands is crucial to help guide restoration decisions with maximum climate benefits. Here, we present results exploring the effects of peat nutrient status (nutrient-rich vs. nutrient-poor) and N loading on microbial processes and GHG (carbon dioxide, methane, and nitrous oxide) production and consumption patterns in two rewetted fens. We used an automated incubation system coupled with a gas chromatograph to monitor microbial functions and GHG dynamics in rewetted peat samples under different treatments. Samples were collected at the start of a running year-long mesocosm experiment, where peat is incubated with controlled N concentrations and vegetation composition.

The start point incubation data show that N loading, but not the inherent peat nutrient status, promoted N related processes such as nitrification and denitrification. Both methane production and consumption were higher in nutrient-rich peat, and were inhibited by the presence of nitrate and ammonium respectively. Methane production kinetics displayed variable patterns between nutrient-rich and -poor peat (higher initial production rate in nutrient-rich peat), yet the total amount of methane produced was similar between fens. Results also suggest that the availability of other electron acceptors than oxygen tended to increase anoxic carbon dioxide production rates in rewetted peatlands. Overall, these findings indicate that differences in chemical composition between the two similar peatland types (fens) can lead to variable GHG dynamics after rewetting, and that controls of soil functions are site-specific.

We aim to use results from the endpoint of the mesocosm experiment (after 1 year of incubation) to investigate the impact of vegetation composition on soil functions, and whether N loading leads to acclimatization of GHG-related microbial functions in rewetted fens using transcriptomics combined with targeted incubations.

How to cite: Gios, E., Emsens, W.-J., van de Putte, I., van Diggelen, R., Verbruggen, E., and Silvennoinen, H.: Controls of soil functions and greenhouse gas emissions in rewetted peatlands, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13069, https://doi.org/10.5194/egusphere-egu23-13069, 2023.

A.293
|
EGU23-15706
Bärbel Tiemeyer, Christian Brümmer, Ullrich Dettmann, Dominik Düvel, Sebastian Heller, Jan Oestmann, Liv Offermanns, Arndt Piayda, and Carla Welpelo

Drained organic soils are large sources of anthropogenic greenhouse gases (GHG) in many European and Asian countries. In Germany, they account for more than 7% of the national GHG emissions. Carbon dioxide (CO2) forms the vast majority of emissions from these soils and is thus the main target for mitigation measures. Bog peatlands are mainly found in North-Western Germany and frequently used for high-intensity grassland use. Further, former peat extraction areas are restored for nature protection. While restoration has decades of tradition, paludiculture and active water management in agriculture are comparatively new.

Here, we will compile data on GHG exchange of bog peatlands and highlight recent results on water management by ditch blocking and subsurface irrigation, on Sphagnum paludiculture and on restored bog peatlands. Groundwater levels are usually considered as the major control for both CO2 and methane (CH4) emissions. The effects of water management on CO2 emissions are strongly depending on the site. Surprisingly, raising the groundwater level by subsurface irrigation in a grassland under bog peat to levels considered as acceptable even in restoration projects did not only fail to reduce CO2 emissions, but raised them compared to deeply drained control parcel. These results might be explained by an interaction of increased soil moisture in the topsoil and improved nutrient retention during phases of high soil temperatures and, at the same time, by limitations of microbial activity due to low soil moisture at the control parcels. However, at a second grassland site with subsurface irrigation, this did not occur, but a combination with grassland renewal caused extremely high nitrous oxide emissions. In contrast, both re-wetting for restoration purposes and Sphagnum farming reliably reduce GHG emission or may even lead to a carbon sink. Here, the effects of the groundwater level on CO2 and, even more, on CH4 emissions in a Sphagnum farming experiment were partially overridden by vegetation development dynamics.

How to cite: Tiemeyer, B., Brümmer, C., Dettmann, U., Düvel, D., Heller, S., Oestmann, J., Offermanns, L., Piayda, A., and Welpelo, C.: Greenhouse gas emissions from bog peatlands subjected to (potential) mitigation meausures, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15706, https://doi.org/10.5194/egusphere-egu23-15706, 2023.

A.294
|
EGU23-13920
|
ECS
Philipp Köwitsch, Bärbel Tiemeyer, Sonia Antonazzo, and Ullrich Dettmann

Conventional agriculture on peatlands requires drainage, but this practice causes high emissions of the greenhouse gases (GHG) carbon dioxide (CO2) and nitrous oxide (N2O). Paludiculture is an option to mitigate these adverse environmental effects while maintaining productive land use. Whereas the GHG exchange of paludiculture on rewetted bog peat, i.e. Sphagnum farming, is relatively well examined, data on GHG emissions from fen paludicultures is still very scarce. As typical fen paludiculture species are aerenchymous plants, the release of methane (CH4) is of particular interest when optimising the GHG balance of such systems. Topsoil removal is an option to reduce the CH4 emissions upon rewetting but retaining a nutrient rich topsoil might foster the biomass growth.

In this project, Typha angustifoliaTypha latifolia, and Phragmites australis are grown at a fen peatland formerly used as grassland. Water levels will be kept at the surface or slightly above it. In parts of the newly created polder surrounded by a peat dam, the topsoil is removed. Four smaller sub-polders are installed to separate the effects of topsoil removal and water level. Here, the water levels can be adjusted independently from the main polder. Greenhouse gas exchange is measured for all three species with and without topsoil removal. Additionally, a reference grassland site close by and a site on the dam are included in the measurements. GHG measurements are carried out every two to four weeks on a campaign basis using manual chambers and a portable analyser for both CH4 and CO2. Here we present GHG balances of the first two years after planting the paludicultures.

Despite of imperfect water management during the first year after planting, all paludiculture species were both a net CO2 and GHG sink regardless the topsoil treatment. During this period, fluctuating water levels resulted in low CH4 emissions while N2O emissions were of greater importance regarding the GHG balance. Due to more stable water levels in the second year, higher methane emissions are expected. Carbon export by the first biomass harvest will also be taken into account.

How to cite: Köwitsch, P., Tiemeyer, B., Antonazzo, S., and Dettmann, U.: Greenhouse gas exchange of different fen paludicultures during establishment, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13920, https://doi.org/10.5194/egusphere-egu23-13920, 2023.

A.295
|
EGU23-3576
Martin Evans, Jonny Ritson, Rebecca Self, Fred Worrall, Chris Evans, and Richard Lindsay

Much of UK upland peat is in a drained and/or degraded state, meaning it is a net source of CO2 emissions to the atmosphere. Typical restoration methods, such as rewetting, can improve this, however most restoration projects only achieve a lowering or cessation of emissions with few achieving a net-negative carbon balance. In this new demonstrator project, Greenhouse Gas Reduction – Peat, we are trialling methods of supressing methane emissions as well increasing carbon sequestration so that carbon negative restoration projects can be achieved.

The projects aims to accelerate the transition from degraded, burn-managed heather (Calluna vulgaris) bog to actively peat-forming bog, while minimising wildfire risk and CH4 emissions. We will present preliminary results and further plans for three techniques, trialled alongside typical gully blocking:

1) Sphagnum planting: This ‘nature-based’ intervention will involve Sphagnum (a peat forming moss species) establishment using micropropagated assemblages of hummock-forming species which show the highest rates of C accumulation. During the first years of Sphagnum growth, CO2 sequestration may be in excess of long-term peat accumulation rates as a functional upper ‘acrotelm’ layer re-establishes. Sphagnum can also act as a CH4 biofilter, improving the net greenhouse gas balance.

2) Heather mowing and biochar production: As an alternative to managed burning, we will harvest old heather biomass using low-ground pressure vehicles, followed by biochar production and re-application. Biomass removal will reduce wildfire risk, while controlled pyrolysis will avoid damage to Sphagnum/peat from burning, and enhance biomass conversion to biochar above that achieved in uncontrolled burns.

3) Suppression of methane production: CaSO4  can supress methane formation by offering a more energetically favourable metabolic pathway to microbes, meaning sulphate reducing bacteria are more active than methanogenic bacteria. This essentially ‘nudges’ the bacterial population in a direction more favourable for greenhouse gas balances.

How to cite: Evans, M., Ritson, J., Self, R., Worrall, F., Evans, C., and Lindsay, R.: Managing UK upland peat for greenhouse gas removal, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3576, https://doi.org/10.5194/egusphere-egu23-3576, 2023.

A.296
|
EGU23-5792
|
ECS
|
Alena Holzknecht, Örjan Berglund, Jacynthe Dessureault-Rompré, Lars Elsgaard, Magnus Land, and Kristiina Lång

Approximately 8.6% of Swedish agricultural soils are classified as organic soils (Berglund et al. 2010). In the early 19th century, the Swedish government drained peatlands to make land suitable for agricultural production (Berglund 2008). When drained, organic soils are a significant source of CO2 because of the breakdown of organic materials (Ballantyne et al. 2014). In order to reach climate national and international climate goals, the agricultural sector has the important task of reducing its climate impact and thus greenhouse gas (GHG) emissions. For this purpose, the European Union and some Nordic countries see potential in changing land use on organic soils to ley production or perennial green fallow as an alternative to rewetting peatlands. However, there is lacking scientific consensus about the effectiveness of reducing GHG emissions using these interventions. In many studies, different sites or years are compared, which limits the comparability between land uses because of the many variables that influence the outcome (Kasimir-Klemedtsson et al. 1997; Maljanen et al. 2001; Lohila et al. 2004; Beetz et al. 2013), and thus the conclusions that can be taken for future policies. This systematic review aims to answer the question of which land use(s) can be suggested as a valid alternative for decreased GHG emissions on organic soils in temperate and boreal climates. 

The review will be conducted by establishing a detailed review protocol, following the Collaboration for Environmental Evidence (CEE) guidelines (Pullin et al. 2022), including a methodology for literature search, eligibility screening, data extraction, and critical appraisal. After implementation of the protocol, and if enough valid data can be found, data synthesis, interpretation and a scientific publication about the outcomes will follow.

 

Sources:

Beetz, S., Liebersbach, H., Glatzel, S., Jurasinski, G., Buczko, U., & Höper, H. (2013). Effects of land use intensity on the full greenhouse gas balance in an Atlantic peat bog. Biogeosciences, 10(2), 1067–1082. https://doi.org/10.5194/bg-10-1067-2013

Berglund, K. (2008). Torvmarken, en resurs i jordbruket igår, idag och även i morgon. In Svensk mosskultur - Odling, torvanvändning och landskapets förändring. (Vol. 41, pp. 483–498). Runefelt, Leif.

Berglund, Ö., & Berglund, K. (2010). Distribution and cultivation intensity of agricultural peat and gyttja soils in Sweden and estimation of greenhouse gas emissions from cultivated peat soils. Geoderma, 154(3), 173–180. https://doi.org/https://doi.org/10.1016/j.geoderma.2008.11.035

Andrew S Pullin, Geoff K Frampton, Barbara Livoreil, & Gillian Petrokofsky. (2022). Guidelines and Standards for Evidence Synthesis in Environmental Management. Guidelines and Standards for Evidence synthesis in Environmental Management. Version 5.1. https://environmentalevidence.org/information-for-authors/ [5-01-23]

Kasimir-Klemedtsson, Å., Klemedtsson, L., Berglund, K., Martikainen, P., Silvola, J., & Oenema, O. (1997). Greenhouse gas emissions from farmed organic soils: a review. Soil Use and Management, 13(s4), 245–250. https://doi.org/https://doi.org/10.1111/j.1475-2743.1997.tb00595.x

Lohila, A., Aurela, M., Tuovinen, J.-P., & Laurila, T. (2004). Annual CO2 exchange of a peat field growing spring barley or perennial forage grass. Journal of Geophysical Research: Atmospheres, 109(D18). https://doi.org/https://doi.org/10.1029/2004JD004715

Maljanen, M., Martikainen, P. J., Walden, J., & Silvola, J. (2001). CO2 exchange in an organic field growing barley or grass in eastern Finland. Global Change Biology, 7(6), 679–692. https://doi.org/https://doi.org/10.1111/j.1365-2486.2001.00437.x

How to cite: Holzknecht, A., Berglund, Ö., Dessureault-Rompré, J., Elsgaard, L., Land, M., and Lång, K.: What is the effect of ley or perennial fallow on the flux of greenhouse gases from arable organic soils?, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5792, https://doi.org/10.5194/egusphere-egu23-5792, 2023.

A.297
|
EGU23-8872
|
ECS
Maarit Liimatainen, Liisa Kulmala, Miika Läpikivi, Timo Lötjönen, Markku Yli-Halla, Jaana Nieminen, Jarkko Kekkonen, Juho Kinnunen, Stephanie Gerin, Henriikka Vekuri, Tung Pham, Iida Höyhtyä, Hannu Marttila, Björn Klöve, Toni Liedes, Tuomas Laurila, Annalea Lohila, Jari Liski, and Erkki Joki-Tokola

To use peatlands for agriculture or forestry, they need to be drained. Lowered water table and increased oxygen concentration in the soil profile alter soil biogeochemistry, enhancing peat decomposition and mineralization processes. After the drainage, peatland changes from carbon sink to carbon source into the atmosphere and watercourses. The drainage affects the greenhouse gas (GHG) fluxes and runoff water quality depending on soil nutrient status and the new water table depth. Usually, carbon dioxide ad nitrous oxide fluxes increase, and methane fluxes decrease.

In Finland, approximately 10% of cultivated fields are on organic soils but they are responsible for a larger share of agricultural GHG emissions. Finland has set a challenging goal for carbon neutrality by 2035, thus the pressure to mitigate GHG emissions from cultivated peatlands is high. However, if the cultivation of drained peatlands was heavily restricted, their local importance creates socio-economic challenges, due to their uneven distribution in Finland. At the same time, recent global and economic circumstances as well as the increased occurrence of extreme weather events have underlined the importance of national food security. During dry growing seasons, cultivated peatlands produce decent crop yields more reliably than mineral soils.

NorPeat research platform (26 ha) located at Ruukki, Finland (64.68°N, 25.11°E) and governed by Natural Resources Institute Finland (Luke) is a cultivated peatland under normal silage grass rotation for beef cattle feed production. The platform was established in 2017 to study various environmental effects of cultivated peatlands monitoring year-round GHG fluxes, as well as flow and the quality of subsurface drainage water and overflow. The field is divided into 8 plots and the peat depth varies from 15 to 75 cm. Water storage reservoir (0.7 ha) located next to the field is connected to the subsurface drainage system and it allows subsurface irrigation and manipulation of the water table level in the individual plots. Environmental conditions are monitored with multiple sensors to supplement the datasets of GHG emissions and leaching. Along with field experiments, we are running column experiments in controlled conditions in the laboratory to study environmental impacts in more detail. In addition, the technical usability of sub-irrigation systems as a tool for GHG mitigation via water table control is studied in the field and laboratory. These are carried out with the aim to add automated features to the system to optimize the operation of the sub-irrigation.

How to cite: Liimatainen, M., Kulmala, L., Läpikivi, M., Lötjönen, T., Yli-Halla, M., Nieminen, J., Kekkonen, J., Kinnunen, J., Gerin, S., Vekuri, H., Pham, T., Höyhtyä, I., Marttila, H., Klöve, B., Liedes, T., Laurila, T., Lohila, A., Liski, J., and Joki-Tokola, E.: Environmental impacts and mitigation options on cultivated peatland with shallow peat depth in northern Finland – NorPeat platform, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8872, https://doi.org/10.5194/egusphere-egu23-8872, 2023.

A.298
|
EGU23-3563
|
ECS
|
Lipe Renato Dantas Mendes and Florence Renou-Wilson

Peatlands comprise a significant share of the land surface in Ireland, i.e. 21%. Degradation of these ecosystems for horticultural industry purposes has exerted pressure on the water quality of surface waters. This occurs due to the removal of hydrophytic vegetation, drainage and exposure of the peat to aerobic conditions, in which the latter disturb the local water regime and accelerate decomposition processes. This subsequently results in significant leaching of carbon and nitrogen compounds such as dissolved organic carbon and ammonia. Despite the above, little study has focused on understanding the effects of peatland degradation on the waters leaving such catchments and therefore adequate mitigation measures.

We hypothesize that the water quality of effluents from such extracted peatlands is highly dynamic, and these effluents are harmful to surface waters all year round. Here we compare the results with environmental thresholds and studies testing the effect of effluents in surface waters. We hypothesize that prolonging the hydraulic residence time of the effluents in situ does not suffice for treatment due to high proportion of soluble nutrients and lack of necessary biogeochemical conditions.

The results presented here are based on long-term monitoring (c. 2 years to date) of an extracted degraded Irish raised bog (53°41'54.9"N 7°24'53.7"W). The site was drained for the extraction of horticultural peat. The drainage network allowed the water to flow into a pond for water treatment including particle sedimentation. Hereby, nutrient discharge from the site to surface waters downstream was expected to be minimised. A YSI EXO2 Multiparameter Sonde installed at the outlet and then at the inlet of the pond allowed continuous (up to 30-min interval) measurements of temperature, pH, conductivity, turbidity, fluorescent dissolved organic matter and ammonium concentration during most of the monitoring period. An area velocity flow meter paired with the Sonde allowed continuous (5-min interval) measurements of flow rate. In addition, a Teledyne ISCO Sampler 6712 installed at the pond outlet ensured time-proportional samplings during 11 storm events to date, i.e. when the pond water level exceeded a threshold. Finally, grab samplings have been periodically conducted at the pond inlet and outlet during the monitoring period. These samplings have been analysed for a series of water quality parameters including carbon, nitrogen, phosphorus and ionic compounds.

Analyses of the data carried out to date corroborate the hypotheses. This includes acidic discharges, and variable and significant outflow concentrations of nutrients in different seasons, as well as minimal treatment in the pond. This subsequently highlights the need of proper mitigation measures in degraded peatland catchments in order to regulate the water quality of the effluents and ensure good ecological status of surface waters downstream.

How to cite: Dantas Mendes, L. R. and Renou-Wilson, F.: Water quality dynamics of an extracted peatland and pond treatment, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3563, https://doi.org/10.5194/egusphere-egu23-3563, 2023.

A.299
|
EGU23-11041
|
ECS
|
Mika Little-Devito, Kevin Devito, and William Shotyk

Horticultural peat harvesting is expanding in Canada with the potential to negatively impact downstream water quality. Previous studies have reported variable responses in outflow nitrogen (N) and phosphorus (P) concentrations associated with peat harvesting operations, which may be due to unaccounted differences in biogeoclimatic setting or harvesting phase. Within a given peatland, major changes occur to its hydrological and physicochemical properties as it transitions through sequential harvesting phases: from a natural peatland, to an extraction field, and finally to a restored peatland. The linkage between hydrology and nutrient export, and the impact on water quality associated with each phase, have not been studied in relation to geology, relief, and climate across the Canadian boreal. This knowledge is crucial to account for the variability in exported nutrient concentrations, accurately determine the relative risk to downstream waterways, and direct best management practices. The objective of this study was to understand the linkages between peatland hydrological connectivity, ditch substrate, and peat harvesting phase on nutrient mobility at two peatlands in the sub-humid, glaciated, boreal region in Alberta, Canada. Water level, volumetric flow rate, ice and aeration depth, electrical conductivity (EC) and pH were measured at natural, newly opened, extracted, and restored peatlands. Chemical analyses of dissolved and particulate N and P were assessed in surface water, groundwater, and at outflow locations approximately once per month from March through October in 2019 and 2021. In situ ion availability was measured in surface peat layers, alongside surface and below ground temperature, soil moisture, and peat aeration in 2021. Compared to natural peatland areas, the results show that harvesting activities greatly decreased natural water storage capacity, encouraged ice formation, and increased spring runoff in a summer runoff dominated landscape. Drainage ditches further increased hydrological connectivity and outflow from extracted peatlands throughout the year. When ditches reached underlying mineral sediments, EC and pH values differed drastically from natural peatland drainage waters. The effect of extraction and ditching on in situ moisture and aeration in extracted surface layers was minimal compared to the natural peatland, despite lowered water tables. In contrast, N and P values varied drastically between the three harvest phases. During extraction, surface peat had elevated ammonium and nitrate availability compared to natural and restored peatlands. Nitrate remained available in the surface peat throughout the year; however, exports were only detected at the outflow when the peat fields were frozen or following large rainfall events. Nitrate was not detected if the hydrological connectivity between the peat field and its outflow was severed. Extracted and restored peatlands had elevated particulate P at field outflow locations compared to natural sites, likely from ditch clearing or loose peat in the process of settling. Clearly, ditch substrate has a major influence on water quality. Further, hydrological connectivity differs with each harvest phase, resulting in contrasting nutrient transformations and export that will continue to evolve as additional peat fields are opened, extracted, and restored.

How to cite: Little-Devito, M., Devito, K., and Shotyk, W.: Influence of hydrological connectivity and ditch substrate on nutrient transformations and export during peat harvesting phases in a sub-humid, glaciated, boreal landscape, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11041, https://doi.org/10.5194/egusphere-egu23-11041, 2023.

A.300
|
EGU23-12374
Line Jourdain, Elodie Salmon, Christophe Guimbaud, Chunjin Qiu, Sebastien Gogo, Bertrand Guenet, Fabrice Jégou, Fattima Lagoun Défarge, and Philippe Ciais

Wetlands are the largest natural source of methane in the atmosphere. How the methane emissions from wetlands will evolve with global change is a subject of debate. In this study, we investigate the interannual variability of methane emissions from a temperate degraded peatland located in the Sologne region (French Region Centre) and test the ability of the land surface model ORCHIDEE to reproduce this variability. The site is instrumented for long term monitoring of the hydrological parameters, greenhouse gas emissions, dissolved organic content and biodiversity. The peat has undergone several perturbations due to the urbanization of the site that led to drainage and invasion by vascular plants (Molinia Caerula, Erica Tretalix). Our study focuses on the 2014-2020 period after a hydrological restoration was undertaken. The model, driven by meteorological data and constrained by in situ hydrological data, primary productivity and total soil carbon, is able to reproduce the general temporal trend in methane emissions. The model is used to investigate the effect of climatological conditions (droughts) and vegetation changes (invasion by vascular plants) on the observed trend of methane fluxes. The model is also used to study the relative contributions of different methane transport processes (by the plants, from ebullition and diffusion) to the methane flux observed in La Guette peatland.

How to cite: Jourdain, L., Salmon, E., Guimbaud, C., Qiu, C., Gogo, S., Guenet, B., Jégou, F., Lagoun Défarge, F., and Ciais, P.: Modelling interranual variability of methane emissions from a temperate degraded peatland, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12374, https://doi.org/10.5194/egusphere-egu23-12374, 2023.

Posters virtual: Tue, 25 Apr, 08:30–10:15 | vHall BG

Chairperson: Hanna Silvennoinen
vBG.10
|
EGU23-12279
|
ECS
ReddyPrasanna Duggireddy and Gilboa Arye

Of all organic materials employed in soilless culture systems, peat is commonly employed as a substrate for crop production. However, the properties of peat may not provide optimal water availability and aeration conditions due to the development of substrates water repellency (WR). Although synthetic surfactants are used to ameliorate WR, their negative environmental impacts demand for an alternative approach. In the past decade, biosurfactants have drawn attention due to their low toxicity, biodegradability and, could potentially be used as an alternative. However, to the best of our knowledge, the rate and extent to which biosurfactant may reduce the contact angle (CA) form on peat surface is currently not investigated. The main objective is this study is to quantify the interplay between Rhamnolipid biosurfactant and WR peat. The study is involved with measurements of dynamic advancing and receding CA of aqueous biosurfactant on peat surface at different velocities and aqueous concentrations, using Wilhelmy plate method. For concentration ranged from 20 to 200 mg/l, the results clearly demonstrated a velocity dependence in the first cycle of advancing/receding CA, and significant reduction in CA hysteresis at higher velocities. In the four subsequent cycles, further reduction in CA and CA hysteresis could be observed for the Rhamnolipid demonstrating its aid to peat wettability. However, for water, higher advancing and receding CA was observed even after five consecutive cycles. In our presentation, the results of advancing and receding CA of Rhamnolipid and water on peat surface will presented and possible mechanism will be discussed.

Keywords: Peat, water repellency, Biosurfactant, advancing and receding contact angle, velocity

How to cite: Duggireddy, R. and Arye, G.: Velocity dependent contact angle hysteresis of Rhamnolipid biosurfactant on peat, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12279, https://doi.org/10.5194/egusphere-egu23-12279, 2023.