Setting realistic targets for peatland restoration in specific areas, requires understanding of the key processes and functional relations in that specific type of peatland. Proper understanding of key processes and feed-back mechanisms, the landscape ecological setting and the limits to ecosystem restoration due to degradation, former and current land use and climate change are crucial in the process of drafting effective restoration strategies for peatlands.
For several examples of European fens and bogs, in a different state of degradation, we present landscape ecological analyses of the system, using geological and hydrological information, peat stratigraphy and former use of the peatland, as well as the actual conditions of the soil and peat layer, vegetation, microbiota and (in)vertebrate fauna. In this framework, we show how GHG exchange and recovery of the vegetation and biodiversity, including key species, is determined by key processes and conditions on different spatial and temporal scales. From this perspective, opportunities and requirements are considered for buffer zones between nature reserves and agricultural or urban environments, as well as the perspectives that paludiculture offers for recovery on a landscape scale. Given the acquired understanding of the actual and potential situation of the different peatland ecosystems, specific restoration goals are set and restoration strategies are developed accordingly.
How to cite: van Duinen, G.-J., Versluijs, R., van Staveren, D., Robroek, B., and Fritz, C.: Setting and reaching restoration targets for GHG exchange, ecosystem services and biodiversity of peatlands require a landscape ecological approach, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19601, https://doi.org/10.5194/egusphere-egu25-19601, 2025.
The UK Climate Change Committee (CCC) has set a target to increase the area of peatlands in good condition to 55% by 2050 through restoration and improved management. However, due to limited data, it remains uncertain how much greenhouse gas a restored peatland emits or sequesters over time, making these interventions difficult to assess.
Northern Ireland has a peat soil coverage of about 242,600 ha, representing approximately 18% of its land area. Around two-thirds consists of semi-natural peatlands, defined as areas that have experienced some human intervention (like grazing and drainage) while retaining natural peatland characteristics. The total greenhouse gas emission from peatlands in Northern Ireland were previously estimated at around 2,232 kt CO2e (Evans et al., 2017), representing 10% of Northern Ireland's total emission. However, some emissions were estimated using the IPCC’s emission factors (Wetlands Supplement, 2013), which may not represent the specific character of peatland in Northern Ireland.
To develop better estimates for Northern Ireland and reduce uncertainty, we measured CO2 and CH4 fluxes to create carbon and greenhouse gas budgets for four semi-natural peat bogs using the eddy covariance method between 2022 and 2024. These sites represent different degrees of human intervention, including a grazed blanket bog, two relatively natural raised bogs with some hydrological intervention, and a recently restored raised bog. Our results show that the IPCC Tier 1 emission factors tend to overestimate the emissions from peatlands in Northern Ireland. In fact, on average, these sites appear to function as net carbon and greenhouse gas sinks, with the grazed blanket bog showing the highest uptake. Here, we present results from these sites, and a discussion on the temporal and spatial dynamics of peatland carbon fluxes.
How to cite: van den Berg, M., Riutta, T., Reeve, E., Thompson, H., Cumming, A., Jovani, J., Oakley, S., Cooper, H., Evans, C., Jordan, P., D'Acunha, B., Bodo, A., and Morrison, R.: Greenhouse gas balance for peat bogs in Northern-Ireland: moving towards Tier 2 emission factors using distributed eddy covariance measurements, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11779, https://doi.org/10.5194/egusphere-egu25-11779, 2025.
Peatlands are the largest terrestrial carbon stores on earth and play a significant role in the global carbon cycle. They become major sources of carbon when drained and degraded through unsustainable management like peat extraction, drainage, and conversion to agriculture and forestry. Restoration through rewetting—such as ditch blocking and bund construction—has been identified as one of the most efficient methods to accelerate biodiversity recovery while lowering carbon emissions and increasing carbon uptake. Since 2021, restoration efforts constructing contoured peat embankments (bunds) have been underway at a raised bog previously drained for horticulture extraction in Ireland. We investigated the net ecosystem exchange (NEE) and methane (CH4) emissions using an Eddy Covariance (EC) system to assess the impacts of restoration on carbon dynamics, with results over a four-year period indicating the site is still emitting carbon after restoration efforts. However, the restored bog comprises a mosaic of land cover types including bare and vegetated peat, open water and bunds and the spatial variation in soil respiration (Rs) across the site remained unknown. To address this, a chamber-based spatial Rs measurement campaign was carried out over a 10-month period. Unmanned Aerial Vehicle (UAV) surveys were also carried out to quantify land cover at the site. Initial findings revealed that the mean CO2 efflux from bare peat and bund were 33.45 ± 2.73 (±SEM), and 60.43 ± 5.61 µmol CO₂ m² h⁻¹, respectively, 1-2 years post-restoration work. The study investigated the relationship of Rs with the explanatory factors such as soil temperature (Ts), soil moisture (Ms), and water-table height (Wt). The correlation analysis showed that in the bund areas, Ts exhibited a positive moderate influence on the Rs, while Wt significantly influence Rs in the bare peat areas. This chamber measurements approach spatially will help us to gain the deeper understanding of carbon dynamics in the restored peatland. It will allow us to capture the variations in carbon flux across the site’s various microtopographic features, which provide valuable insights for refining peatland restoration strategies and design methods to mitigate climate change mitigation effectively.
How to cite: Naughton, O., Shamsuzzaman, M., Regan, S., O'Connor, M., Casey, I., and McCarthy, U.: Understanding Carbon Emissions in a Drained Peatland Undergoing Restoration: Insights from Chamber-Based Measurements, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18864, https://doi.org/10.5194/egusphere-egu25-18864, 2025.
Natural peatlands are significant reservoirs and sequesters of carbon, important modifiers of local hydrology through their high water retention capacity, and unique habitats of rich biodiversity. The exploitation of peatlands by drainage for land-use purposes, such as peat mining or forestry, disrupts the original peatland ecosystem and leads to the degradation of the peat carbon storage, turning the soil from a sink into a source of greenhouse gases. Restoring drained peatlands aims to improve the water regime and carbon sink functions by re-establishing pre-disturbance conditions, ultimately restoring the ecosystem to a state where peat accumulation resumes. How fast and to what extent restoration goals are reached depend e.g. on the properties of the pristine peatland before drainage as well as the level of disturbance by the post-drainage land-use. Quantifying the greenhouse gas balances of restored peatlands is crucial for assessing the effectiveness of restoration as a climate change mitigation strategy, but it necessitates long-term monitoring of greenhouse gas exchanges. However, due to their vast diversity, there is limited research coverage on the various types of peatlands undergoing restoration, as well as a lack of data from the from periods beyond the first five years after rewetting.
This study presents and compares the annual balances of CO2, CH4 and N2O for two forestry-drained bogs restored five years ago and two natural bogs, located in Estonia. For this we apply a field measurement-based modelling approach, utilising data from manual soil surface measurements of greenhouse gas fluxes conducted bi-weekly from November 2023 to October 2024, accompanied by continuous measurements of soil water content, soil water table level, soil and air temperatures and photosynthetically active radiation. The year-round CH₄ and N₂O fluxes, as well as the non-growing season net ecosystem exchange (NEE), were determined from series of gas samples collected from static, opaque chambers and analysed by gas chromatography. During the growing season, NEE was derived from gas flux measurements using a transparent dynamic chamber connected to a portable CO2 gas analyser. To account for spatial heterogeneity, the gas flux measurements were conducted across different microtopographical features and vegetation: hummocks, hollows, and spots dominated by cotton grass (Eriophorum vaginatum). The annual greenhouse gas balances are compiled from daily-level fluxes, which are modelled based on their dependencies with the environmental parameters.
How to cite: Tenhovirta, S., Schindler, T., Mander, Ü., Espenberg, M., Truupõld, J., Kamil-Sardar, M., and Soosaar, K.: CO2, CH4 and N2O balances of restored forestry-drained and natural peatlands in Estonia , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9657, https://doi.org/10.5194/egusphere-egu25-9657, 2025.
Wet fen meadows are a traditional form of land use that is nowadays mainly preserved through nature conservation measures. Recent discussions suggest that this land use may also be considered as a form of paludiculture (that is, wet peatland use with the preservation of the peat body). However, the climate effect of this land use type is largely unknown. My presentation shows a complete two-year greenhouse gas (GHG) balance of two previously unexplored, long-term rewetted fens under a nature conservation management regime resulting from biweekly chamber measurements of GHG fluxes at two north-east German sites with acute sedge and at one site with creeping bentgrass from 2014 to 2016. Including harvest and dissolved carbon export, the three sites emitted between 10.4 and 16.3 t CO2-eq ha-1 yr-1, with mean annual water levels between -10 and -19 cm. Emissions consisted mainly of CO2 uptake and release and were influenced by harvest time and frequency as well as inundation periods during vegetation growth. In addition, CH4 emissions contributed to the net GHG balance at two sites due to inundation in late summer 2014. N2O emissions were of minor importance at all three sites. The presentation demonstrates that, depending on proper water management, nature conservation-managed fen meadows can have a similar climate effect as other fen paludicultures, with a GHG mitigation potential of between 15 and 20 t CO2-eq ha- 1 yr-1 compared to drainage-based grassland use on fens.
How to cite: Wolf, R.: Managing wet fen meadows for nature conservation leads to a moderate warming effect, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1354, https://doi.org/10.5194/egusphere-egu25-1354, 2025.
Peatlands are globally significant ecosystems with high organic carbon storage capacity due to slow litter decomposition in water-saturated soils promoting anoxic conditions. However, these ecosystems are increasingly threatened by climate change and land-use pressures. In the Pyrenees, mountain peatlands have become relict ecosystems, reduced to small isolated areas of just over one hectare. There, hydrological conditions and vegetation cover are severely impacted by rising temperatures, reduced water availability, and intense livestock activity from large animals (i.e. horses and cows). Effective management strategies to mitigate potential large greenhouse gas (GHG) emissions from these ecosystems are urgently needed.
The ALFAwetlands and Pyrepeat projects investigate the effects of grazing exclusion (i.e. enclosures installed in 2016) and hydrological variation (i.e. strong seasonality) on GHG fluxes in two Pyrenean peatlands, Rubió (42.41º N, 1.24º E) and Estanyeres (42.61º N, 1.05º E). Both peatlands are characterized by contrasting pH (5.97 ± 0.08 and 7.78 ± 0.21, respectively) and water saturation levels. Over two years, monthly measurements of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) emissions were conducted across three plot types outside and within grazing exclusion zones: (1) low livestock trampling and soil disturbance, with barely vegetation gaps (mosses and sedges species); (2) pugged soils with wide exposed peat areas increasing CO2 oxidation potential, and large vegetation gaps; (3) peatland margin areas with the driest condition, rarely flooded, and continuous vegetation cover of grass-like plants. Within the enclosure, these three types of plot were identified before fences were installed and nowadays they are partially recovered.
Preliminary results highlight the vulnerability of these ecosystems to climatic changes. CO2 emissions were highest in dry plots of both peatlands, where reduced water content accelerated organic carbon oxidation. In the drier peatland, emissions were further amplified outside exclusion zones. CH4 emissions were higher in the wetter peatland, consistent with anaerobic conditions that promote methanogenesis, while N2O emissions remained consistently low across both sites due to nitrogen limitation.
These findings emphasize that climate-driven drying poses a significant threat to peatlands by increasing CO2 emissions, a risk that is exacerbated by livestock disturbances. Management actions such as grazing exclusion are critical to maintain peatlands’ carbon storage capacity and mitigate GHG emissions from these vulnerable ecosystems. This research contributes to the growing body of knowledge needed to align peatland conservation and restoration with climate change adaptation.
How to cite: Poblador, S., Escarmena, L., Bautista-Medina, B., Grundeus, A., Martinez-Amigo, V., Anaya, I., Ninot, J. M., Pérez-Haase, A., and Sabater, F.: Carbon Under Threat: Insights from Grazing Exclusion and Climate Impacts in Pyrenean high mountain peatlands, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13008, https://doi.org/10.5194/egusphere-egu25-13008, 2025.
Peatland de-vegetation and surface erosion are common facets of peatland degradation in the uplands. These processes impact peatland function by limiting plant-derived carbon input, exposing previously deep peat to near-surface conditions, and disrupting peatland hydrology. Restoration of eroded peatlands typically aims both to re-establish vegetation cover and raise water tables. Here we present the impacts of physico-chemical alterations resulting from severe erosion and subsequent peatland recovery on microbial communities in a temperate upland bog. Due to the central role of microbes in peatland organic matter decomposition, understanding their response to restoration measures is key to determining the success of these interventions.
We determine key physico-chemical variables which control the composition of microbial communities and shape their function. By coupling detailed characterisation of geochemistry and the microbiome, the consequences of microbial community shifts for the peatland carbon store are considered. In upland ombrotrophic peat, where recovery has proceeded on formerly eroded surfaces, organic matter quality as investigated by pyrolysis-GCMS is presented and is determined to be a stronger predictor of community composition than water table position. Using amplicon sequencing we identify distinct microbial communities under degraded and re-vegetated surfaces, with significant depth relationships only present in peat which was actively accumulating. Re-vegetated areas support higher microbial biomass, with elevated dissolved organic carbon and CO2 concentrations evidencing altered carbon cycling following recovery. Functional profiling with shotgun metagenomics further reveals contrasting life-strategies which reflect the availability of organic substrates. Whilst water table position is often the primary control on peatland microbial function, we found this relationship to be obscured by the stronger role of organic substrate limitation in this eroded context. We discuss the consequences for restoration of eroded temperate peatlands where deep peat has been exposed.
How to cite: Ring-Hrubesh, F., Eberle, A., Gallego-Sala, A., Welch, B., Pancost, R., Griffiths, R., and Bryce, C.: Legacy of peatland erosion continues to shape microbial communities during recovery. , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18923, https://doi.org/10.5194/egusphere-egu25-18923, 2025.
Peatlands host the largest store of terrestrial carbon on Earth and it is widely accepted that reversal of their widespread degradation is required to meet emissions targets. Thus, significant action is underway globally to encourage their rewetting and restoration. However, restoration success can be complicated by geological factors in the local environment. Peatlands in regions with iron sulphide-rich rocks and sediments experience drastic drops in pH following drainage and release high concentrations of iron and toxic metals. Accumulation of iron and sulphur in the peat during this time will fundamentally alter biogeochemical cycling, yet we have little understanding of the extent to which these effects can be reversed following the raising of water tables. Furthermore, the long-term impacts on resident microbial communities responsible for dictating the nature and scale of green-house gas emissions from such sites is unknown.
We have compared two neighbouring fens in southern England underlain by glauconite- and pyrite-rich sandstone which are within the same hydrological regime but have experienced differing degrees of historical drainage and degradation. Both fens were designated for conservation and rewetted in the 1970s. Porewater nutrient and greenhouse gas profiles, peat geochemistry, mineralogy and microbial community analyses collectively suggest lasting differences in redox state and element cycling between the two areas. Wolferton Fen, which experienced less historical land disturbance, had returned to a near-natural state in 2022. However, Dersingham Fen, which was historically deeply drained and experienced significant peat loss, had a low pH, thick crusts of iron (oxyhydr)oxides remaining on the surface, and very high porewater iron and sulphate concentrations. High abundances of these alternative terminal electron acceptors inhibit methanogens in Dersingham Fen, which continues to be a source of CO2 despite anoxia.
These results suggest that iron and sulphur-rich peatlands can tolerate some degree of degradation, but extensive drainage and peat loss will likely lead to permanent contamination which remains following rewetting. However, there may be a lot to gain from restoration of such sites as rewetting can protect remaining peat and reduce CO2 emissions whilst methane production would remain low.
How to cite: Bryce, C., Eberle, A., Ring-Hrubesh, F., Biswakarma, J., Dehaen, E., Pancost, R., and Gallego-Sala, A.: Long-term biogeochemical consequences of rewetting iron and sulphur-rich peatlands, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16729, https://doi.org/10.5194/egusphere-egu25-16729, 2025.
The Flow Country in the Scottish Highlands spans 400,000 hectares of actively accumulating peat bog, providing critical habitat and serving as a vital source of rivers essential for Atlantic salmon (Salmo salar) recruitment. Recognized for its outstanding ecological value, it recently achieved UNESCO World Heritage Site status. However, historical land-use changes, including drainage and forestry plantations, have degraded large areas, transforming them into sources of carbon emissions and compromising water quality. Restoration efforts, particularly forest-to-bog restoration, aim to reverse these impacts, yet their effects on freshwater quality and ecosystem health remain underexplored, especially concerning Atlantic salmon in upland peatland catchments. This study assesses the effects of forest-to-bog restoration on water quality (nutrients, dissolved metals, suspended sediments, dissolved organic carbon, and colour) and evaluates the implications for freshwater ecosystems, with a focus on macroinvertebrates and salmon populations. Short-term changes in water quality were observed in smaller streams draining restoration areas, particularly during the first three years, but these differences diminished over a decade. Importantly, no significant ecological impacts on macroinvertebrates or salmon populations were detected. Moreover, downstream dilution ensured that larger rivers maintained high water quality standards throughout the study. Our findings suggest that well-managed peatland restoration poses no lasting harm to freshwater ecosystems, even when short-term water quality challenges occur. However, high-water temperatures recorded during the study highlight climate change as a critical threat to cold-adapted species like salmon. This research underscores the importance of adaptive management, long-term monitoring, and large-scale restoration efforts that incorporate climate change mitigation strategies to safeguard the ecological integrity of peatland-dominated landscapes.
How to cite: Godwin, L. J., Andersen, R., Gaffney, P., Hancock, M., Youngson, A., and Geris, J.: From landscapes to freshwater invertebrates: understanding the effects of peatland restoraiton on Atlantic Salmon (Salmo salar) habitat in the Flow Country., EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1487, https://doi.org/10.5194/egusphere-egu25-1487, 2025.
Northern peatlands store ~500 Pg C and are important ecosystems for global climate regulation. Wildfire is the largest natural disturbance to peatlands within the Boreal Plains of western Canada. Historically, low-severity fires in this region release less carbon than accumulates over a fire return interval (~120 years), allowing peatlands to maintain their carbon sink function. While peat combustion (measured as the depth of burn; DOB) is typically low, ranging from 5-10 cm (representing carbon emissions of ~1 kg C m-2), during prolonged drought, or in drained peatlands, peat burn severity can reach depths >1 m (~100 kg C m-2), threatening the carbon sink function of boreal peatlands. We aimed to assess how peatland drainage altered the spatiotemporal variability in forest cover, aboveground biomass, and tree productivity and how these changes related to the spatial variability in peat burn severity from a fire 24 years post-drainage. Using remote sensing techniques, forest cover and biomass were estimated through time and with distance from the nearest ditch. Field surveys and a LiDAR-based analysis were conducted to measure the spatial variability in peat burn severity. Peatland drainage increased forest cover and aboveground biomass. Drained peatland margins had the greatest peat burn severity with a mean depth of burn of 26.9 ± 12.6 cm (34.0 ± 10.1 kg C m-2) and some locations experienced DOB >90 cm (>87 kg C m-2), where peat burn severity increased with proximity to drainage ditches and greater aboveground biomass. Peatland drainage increases both aboveground and peat fuel loads through the triggering of positive peatland drying feedbacks which increase peatland vulnerability to deep smouldering, with peatland margins experiencing the greatest peat burn severity. Drained peatlands represent a severe fire risk that can be challenging for communities and fire management agencies. Peatland restoration should be integrated into fuel management strategies to reduce the fire risk that drained peatlands pose.
How to cite: Verkaik, G., Eckert, M., Wilkinson, S., Moore, P., and Waddington, M.: Fuel loads and peat smouldering carbon loss increase following peatland drainage, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-4542, https://doi.org/10.5194/egusphere-egu25-4542, 2025.
Rates of peat extraction have rapidly declined in Finland, leaving thousands of hectares of formerly cutaway peatlands in need of management. Unlike in some other regions, in Finland there is no obligation to restore former peat extraction sites to wetlands. Afforestation is the most popular after use option of cutaway peatlands by landholders in Finland, however it is unclear how the ecosystem will respond to afforestation and whether the system can become a carbon sink quickly. In this study, we present a 3-year record of eddy covariance measurements from an afforested cutaway peatland site in Finland. We examined the carbon dioxide (CO2)exchange dynamics of the site as it was afforested and calculated annual totals to determine whether it is a carbon source or sink.
The study site, Naarasneva, is in Southern Ostrobothnia, Finland. Peat extraction ceased in 2020 and there is an average of 1 m depth of peat remaining. The eddy covariance system was installed in August 2021. Wood ash fertilisation was applied in January 2022, followed by the planting of 2-year old Pinus sylvestris (Scots pine) saplings in June 2022. Sentinel-2 derived leaf area index (LAI) observations were used to investigate the revegetation of the site during afforestation.
The timeseries of NEE shows the exchange (uptake and emission) of CO2 increasing over time. There was a clear effect of fertilisation, with a steady increase in the amount of CO2 uptake in the months following fertilisation. After fertilisation, the most dominant vegetation species growing were Calamagrostis spp. (reedgrass), Epilobium spp. (willow herb) and Betula pubescens (downy birch). The increase in CO2 uptake corresponded well with the LAI observations, which also showed a year on year increase. Annual totals of NEE show the site was a net source of 5.30 ± 0.46 t CO2 ha-1 yr-1 (mean ± 95% CI) in 2022, followed by two years where it was a net sink of -1.36 ± 0.42 t CO2 ha-1yr-1 in 2023 and -0.75 ± 0.56 t CO2 ha-1 yr-1 in 2024.
Our results show that afforestation of a cutaway peatland can quickly turn the site into a carbon sink. While it is positive that the carbon sink functionality of former peat extraction sites may be restored quickly, the long-term climate impact of afforestation is unclear due to the continued drainage of the peat and the uncertain fate of the carbon stored in wood.
How to cite: Buzacott, A., Laasasenaho, K., Lauhanen, R., Minkkinen, K., Ojanen, P., and Lohila, A.: Afforestation turns cutaway peatland into a carbon sink, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9706, https://doi.org/10.5194/egusphere-egu25-9706, 2025.
This study evaluates the impact of different forest management practices on soil greenhouse gas (GHG) fluxes in the Ränskälänkorpi boreal drained forested peatland, in Southern Finland. The study site is part of the HoliSoils project (Holistic management practices, modelling, and monitoring for European forest soils; https://holisoils.eu/). The study is designed for a comparative analysis of non-harvested control, traditional clear-cut harvesting, and harvesting by continuous cover forestry (57% of basal area removed), carried out in spring 2021. The aim is to quantify mean differences in soil CO2, CH4, and N2O emissions and improve the annual budget estimates.
Measurements of soil CO2, CH4, and N2O fluxes, soil temperature, moisture, water table depth, and air temperature were conducted post-harvest every two weeks during the growing season (May to November). Soil chemistry, understory vegetation, and microbial populations were also surveyed and evaluated for relations to observed spatial patterns of the GHG fluxes. Machine learning and Bayesian data assimilation techniques were employed (i) to identify relationships between GHG fluxes and environmental variables, and (ii) to model spatio-temporal dynamics.
Clear-cutting (CUT) resulted in an immediate and sustained rise in the water table, with mean levels significantly higher than the control (CTR) and selection harvesting (COV) sites. In all CUT, COV, and CTR sites differences in mean values of soil CO2, CH4, and N2O fluxes were significant.
Our findings underscore the significance of spatio-temporal variability in GHG fluxes across different management practices, highlight the management role in variation of dynamic environmental controls on CO2, CH4, and N2O fluxes, and reduce the knowledge gap on the effects of harvesting methods on GHG fluxes in boreal drained forested peatlands.
How to cite: Tupek, B., Lehtonen, A., Anttila, J., Li, Q., Martinez Garcia, E., Martinovic, T., Baldrian, P., and Mäkipää, R.: Effects of alternative harvesting managements on spatio-temporal variability of soil CO2, CH4, and N2O fluxes in boreal drained forested peatland, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20075, https://doi.org/10.5194/egusphere-egu25-20075, 2025.
Water quality can be negatively impacted by tree felling operations and peatland restoration. This research considers how different and innovative brash (a by-product of felling trees - their tops and branches) management techniques might impact water quality following forest felling and subsequent peatland restoration.
The research design consisted of a Before-After Control-Impact experiment, wherein three different management techniques on three paired sites were compared. Two of these techniques are standard for the industry: conventional felling of trees, and the mulching of trees in-situ followed by ground smoothing. The third technique (felling multiple drifts of trees into one followed by ground smoothing) is novel and endorsed by the Scottish Government but it has not been studied previously.
Every four weeks (for 32 months) water samples and water table depths have been taken in and around treated sites. Water samples are tested for a range of water quality parameters in the laboratory. These quality indicators included: phosphate, ammonium, nitrate + nitrite, dissolved organic carbon, heavy metals, suspended solids, pH, conductivity, turbidity, etc.
Findings show that the novel technique resulted in little water quality impact (i.e., on suspended solids and nitrate + nitrite) in impacted watercourses. A spike (4.0 - 8.7 fold, mean 35.1) in ammonium occurred around one year after works were completed, and phosphate and potassium showed an elevated pulse soon after the works. Dissolved organic carbon showed strong seasonality which mirrored the control sites.
The novel technique considered here is an understudied method that is being recommended by Scottish Government agencies, and as such, science is chasing industry practice. This research aimed to sense check the impact of this technique on water quality and consider how it may impact the effectiveness of peatland restoration.
How to cite: McWilliam, A., Gaffney, P., Shah, N., and Taggart, M.: Science chasing industry: Is this novel technique as good as it seems?, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-966, https://doi.org/10.5194/egusphere-egu25-966, 2025.
Under the umbrella of international and European Union climate policies and agreements aimed at achieving climate neutrality and thus reducing greenhouse gas (GHG) emissions from drained organic soils (including the Paris agreement, the European Green Deal and the Nature Restoration Law), it is urgently necessary to estimate GHG fluxes from former peat extraction fields to provide measurement-based recommendations for further management of these areas. In addition, there is lack of quantitative estimates of contribution of peatland plant cultivation, including berries, to total GHG emissions and climate change mitigation. Here, we compared carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) fluxes from nutrient-poor organic soils (Histosols) in former peat extraction fields currently used for cranberry (Vaccinium macrocarpon) and highbush blueberry (Vaccinium corymbosum) plantations, active peat extraction fields and pristine raised bogs. GHG flux measurements were conducted over two years using a manual chamber technique at 16 study sites (at least three sites of each land-use type) across 11 different raised bogs in the hemiboreal vegetation region of Europe (in Latvia). Across the studied land-use types, mean annual net CO2 fluxes, calculated as the difference between the annual soil heterotrophic respiration and the annual C input into soil with plant litter, ranged from near zero (-0.07 ± 0.68 t CO2-C ha-1 y-1) in the pristine raised bogs to 1.56 ± 0.19 t CO2-C ha-1 y-1 in active peat extraction fields. Furthermore, net CO2 fluxes had the largest contribution to total GHG emissions in both active peat extraction fields and berry plantations. The lowest annual CH4 fluxes were observed in cranberry plantations (6.65 ± 1.77 kg CH4-C ha-1 yr-1), while the highest were in pristine raised bogs (128.0 ± 27.5 kg CH4-C ha-1 yr-1), where CH4 fluxes accounted for the largest share of total GHG emissions. Annual N2O fluxes did not exceed 0.65 ± 0.33 kg N2O-N ha-1 yr-1 (in highbush blueberry plantations) and made a relatively low contribution to total GHG emissions compared to net CO2 and CH4 fluxes. Across the studied land-use types, the highest total GHG fluxes (the sum of annual net CO2, CH4 and N2O fluxes considering global warming potential values for a 100-year time horizon) were observed in active peat extraction fields (6.23 t CO2 eq. ha-1 yr-1), while the lowest were in cranberry plantations (1.50 t CO2 eq. ha-1 yr-1).
Acknowledgments: The research was conducted within the scope of the European Commission LIFE Climate Action Programme Project “Peatland restoration for greenhouse gas emission reduction and carbon sequestration in the Baltic Sea region” (LIFE21 - CCM - LV - LIFE PeatCarbon, Project number: 101074396).
How to cite: Bārdule, A., Meļņiks, R. N., Zvaigzne, Z. A., Purviņa, D., Skranda, I., Prysiazhniuk, O., Maliarenko, O., and Lazdiņš, A.: Carbon dioxide, methane and nitrous oxide fluxes from former peat extraction fields currently used for cranberry (Vaccinium macrocarpon) and highbush blueberry (Vaccinium corymbosum) plantations, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15398, https://doi.org/10.5194/egusphere-egu25-15398, 2025.
Paludiculture is the productive use of wet or rewetted peatlands. Typha spp. is a promising paludiculture crop with usage options, including as building or insulation material. As part of the Paludi-PROGRESS project (Putting paludiculture into practice – optimization of cattail and reed cultures, project period 2022-2025) a mesocosm experiment was conducted to assess the above- and belowground biomass production and decomposition of Typha latifolia and Typha angustifolia to different water level treatments.
Using non-destructive sampling methods, we examined the annual biomass production of T. latifolia and T. angustifolia from April 2023 to April 2024 in response to either a water level gradient of -20 to +6 cm or to a drought gradient of 2 to 11 weeks. Phenospex PlantEye was used to assess the aboveground biomass production with a multi-spectral scanner. Belowground biomass production was examined with minirhizotrons and decomposition was assessed using litter bags.
At higher water levels, T. angustifolia showed higher aboveground biomass production whereas T. latifolia had higher aboveground biomass production at lower water levels. The latter also expressed higher belowground biomass production at lower water levels, whereas T. angustifolia’s belowground biomass response shifted during the vegetation period, benefitting from higher water levels until June 2023, afterwards showing higher belowground biomass production at lower water levels. Whereas both species benefit from short drought periods (2-4 weeks) with increasing belowground biomass production, longer drought periods negatively affected both species above- as well as belowground biomass production. T. angustifolia seemed to be more resilient against drought than T. latifolia. Information about the optimal water level and drought resistance of potential paludiculture crops are important information for a successful cultivation of Typha spp.
How to cite: Brendel, M., Joshi, S., and Kreyling, J.: Impact of water levels on Typha spp. in a mesocosm experiment, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10318, https://doi.org/10.5194/egusphere-egu25-10318, 2025.
The Paludi-PROGRESS project (Paludiculture in practice: Optimisation of cattail and reed cultures, project period 2022-2025) aims to test and further develop the cultivation of cattail (Typha spp.) as a new permanent crop on wet peatlands. One of the main tasks is to evaluate the productivity and biomass quality of cattail on a 10 ha rewetted peatland, established in September 2019.
In the time period of 2021 until 2024 biomass samples were collected twice a year, in summer (July) and winter (November/December). Prior to the first sampling in 2021, four different density categories were identified based on the visual impression of the cattail vegetation (dense to rare cattail plant occurrence). Sampling plots were randomly distributed within these sub-areas of the pilot site (10 per density category). Since a partial harvest took place on a small area in December 2021 and 2023, the influence of cutting on the biomass could also be observed in the following years. Furthermore, the site was fully harvested at the beginning of 2023. To monitor the cattail vegetation, several parameters were recorded for each plot: e.g. number of cattail plants and spadices, plant height and diameter, dry weight, water content and chemical composition (carbon, nitrogen, phosphorous, potassium, lignin, cellulose and hemicellulose).
From winter 2021 to winter 2024, cattail biomass productivity has more than tripled from 1.8 to 6.8 t dm/ha when considering the total pilot site. In the areas with dense cattail vegetation, the biomass increased from 4.1 to 8.2 t dm/ha. Different stand densities showed an influence on morphological parameters, but had a minor effect on the chemical composition of the biomass. The harvest trial in 2021 did not have a significant impact on the parameters considered. In winter 2023, the biomass productivity declined to 3.6 (total site) and 4.9 t dm/ha (dense areas). Next to other environmental factors, harvesting the total site could have shown a negative effect on the regrowth of cattail in 2023.
The collected data show unique results about the development of cattails on a large-scale pilot site and therefore provide important information for future use of cattail from commercial-scale cultivation. Additionally, it is important to evaluate whether the given growing conditions lead to appropriate biomass quality for various utilization options.
How to cite: Köhn, N., Brendel, M., Neubert, J., Wichmann, S., and Kreyling, J.: Productivity and biomass quality of cattail (Typha spp.) on a 10 ha paludiculture pilot site in northeast Germany, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10490, https://doi.org/10.5194/egusphere-egu25-10490, 2025.
Drained agricultural peatlands are a large source of greenhouse gasses (GHGs) due to peat oxidation. Paludiculture, where flood-tolerant grasses are grown on rewetted peatlands, might be a potential strategy for climate change mitigation by reducing GHG emissions while maintaining biomass production. This study assessed the impact of different harvest and fertilization treatments of reed canary grass (Phalaris arundinacea, cv. Lipaula; RCG) on GHG exchange dynamics and global warming potential (GWP) in two measurement periods (5 May 2020 to 4 May 2021, and 18 May 2021 to 17 May 2022) at a fen with shallow water tables depths (annual mean WTD of -10 cm and -8 cm, respectively) and ca. 2 m deep peat. RCG was established in 2018 and in the following years management strategies with 2 or 5 cuts per year were compared with a non-harvested scenario (0-cut). Treatments involving 2 and 5 annual cuts were fertilized with 200 kg N ha-1 yr-1 in equal split doses for each cut while the 0-cut scenario remained unfertilized. Fluxes of CO2, CH4, and N2O (only 2020-21) were measured with fortnightly intervals using the manual chamber technique and cumulative fluxes were derived by empirical models.
Yields of RCG decreased slightly over the years with 15.6, 11.5 and 8.9 t DM ha-1 yr-1 for the 2-cut system and 14.5, 9.4 and 8.6 for the 5-cut system in 2019, 2020 and 2021, respectively. Mean annual WTD of -13 cm in 2019 was slightly lower than the following years. In general, photosynthetic CO2 uptake was higher in treatments with active biomass management, but carbon export in the harvested biomass offset this benefit, resulting in a near-equal net ecosystem carbon balance (NECB) across all treatments ranging from 36.0 to 43.6 and 17.1 to 28.2 t CO2 ha-1 yr-1 in 2020-21 and 2021-22, respectively. The mean NECB of 22.5 t CO2 ha-1 yr-1 in 2021-22 across treatments was significantly lower than the mean of 38.7 t CO2 ha-1 yr-1 in 2020-21. This might be partly explained by the slightly increasing WTD due to lack of ditch maintenance and more precipitation, but the flux effect of increasing WTD on decreased peat oxidation may also be delayed by a few years. Emissions of CH4 remained low during 2020-21 (1.1–1.9 t CO2e ha-1 yr-1), while N2O emissions were relatively high (4.0-5.7 t CO2e ha-1 yr-1) without any treatment effects. In 2021-22, CH4 emissions increased to 2.6-3.7 t CO2e ha-1 yr-1 equivalent to 11.3 % of the total carbon emission in CO2 equivalents. Although the peat field seemed uniform, large variation within treatments was seen across the experimental blocks which could be linked to differences in soil nutrient concentrations and water chemistry. Overall, it can be concluded that paludiculture and the non-managed restoration scenario exhibited comparable climate outcomes thereby offering flexibility in land-use options for peatland restoration. However, results also suggested that biomass harvest can reduce GHG emissions in the more productive area, while leaving the biomass unmanaged was advantageous in the less productive area of the field.
How to cite: Lærke, P. E., Pullens, J. W. M., Christiansen, J. R., Larsen, K. S., and Rodriguez, A. F.: Two years of GHG emissions from reed canary grass under different harvest management intensities in a rewetting fen peatland, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11328, https://doi.org/10.5194/egusphere-egu25-11328, 2025.
To meet climate targets, drained peatlands will need to be rewetted, thereby reducing greenhouse gas emissions from agricultural landscapes. However, possibilities for continued productive use of these landscapes are also necessary. A novel concept that has emerged in recent years is peatland photovoltaics (PV) in combination with peatland rewetting. Until now, there is almost no practical experience with peatland PV on rewetted peat soils; our project explores the biodiversity of a ‘wet’ peatland PV site.
For a comprehensive understanding of the biological implications of rewetting and solar power generation, a multi-taxon study is being conducted on vegetation, spiders, carabid beetles, birds, amphibians and bats. Paired with traditional field survey techniques, methods from the rapidly evolving field of bioacoustics including passive acoustic monitoring and machine learning are being used to gather data from the entire growing season. This presentation will provide initial results on plant and bird biodiversity at a 30-hectare rewetted peatland PV site in Northern Germany. A space-for-time approach was used to assess biodiversity in a drained, intensively used peatland site compared to the rewetted solar park. Initial results indicate that while species diversity is not significantly different, the plant community is. The plant community within the rewetted solar park has more species adapted to wet conditions, while the species within the drained peatland site are largely typical agricultural species.
Given the need to rewet peatlands and the rapid growth of the solar power industry, it is necessary to understand the biological implications of such a land use, as well as any possibilities for synergies between climate protection and renewable energy production.
How to cite: Martens, H. R., Kreying, J., and Tanneberger, F.: Biodiversity Potential in Solar Parks on Rewetted Peatlands, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10373, https://doi.org/10.5194/egusphere-egu25-10373, 2025.
Measurable restoration targets, and indicators of success for restoration are critically required for restoration programmes to successfully measure and appraisal of interventions.
Traditionally this has been done by a combination of hydrology monitoring, vegetation surveys and GHG emissions monitoring. These methods can be both costly in terms of time and money and are not always included as part of traditional UK-based conservation and restoration funding criteria written by the funding providers, such as landfill tax and government funding.
They also require trained practitioners or partnership working (e.g. with academia or specialist consultancies) to do effectively, especially at the scale needed to meet the target of 282 thousand Ha of peat being actively under restoration by 2050, as set by the British government as part of the Peat Action Plan (PAP) in 2021.
One of the major challenges of assessing restoration efficacy is the lengthy period needed to reach any restoration targets and the therefore associated long-term monitoring needed to measure this. The processes at work can take decades to reach completion, resulting in costly and far-sighted monitoring programmes.
This research aims to develop a tracer for peatland status based on elucidating the extent to which old C stored within degraded and rehabilitated peatland sites is being emitted. It will do this by delineating the relationships between the age of respired soil carbon (C) being lost from peatlands and current, historical, and restorative land management of sites.
This research applied highly novel application of 14CO2 and dissolved 14CO2 (D14CO2) Carbon dating of the soil and fluvial emissions across the time chrono-sequence of a lowland-raised bog restoration programme and combine with data on CO2 soil emissions (NER) and primary productivity data (GPP) to aid in the characterisation of emissions for each site. This approach aims to provide an insight into the stability of the peat horizon, the role of modern and older carbon mobility plays across restoration strategies and the estimated depth at which emissions originate. Emissions were captured using molecular sieves connected from closed chambers, with flux passively sampled over a 1-month period. This was combined with fluvial D14CO2 samplers deployed in parallel in adjacent ditches to compare the difference in ages between soil respiration and fluvial emissions.
This simple tracer could revolutionise peatland conservation science through providing an accessible, quantitative approach to assessing the extent to which C lost is either dominated by modern C gained from recent plant grown or C respiration of older, deeper organic matter stores (representing a net loss of stored C to the atmosphere). As reinstatement of stable, long-term C storage is one of the key aims of conservation bodies, government, and landowners, assessing this directly would seem an obvious and important measure especially with funding shortfalls identified leading to a more blended funding approach to peatland restoration.
How to cite: Longden, M., Nolan, M., Garnett, M., Page, S., and Evers, S.: 14C dating of peat surface - emitted dissolved fluvial CO2 carbon to support management and decision-making for UK Lowland peatlands, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20993, https://doi.org/10.5194/egusphere-egu25-20993, 2025.
Human industry has contaminated peatlands through the atmospheric deposition of pollutants released by industrial processes over many centuries. Relative to other ecosystems, peatlands sequester a far greater proportion of toxic metals than their areal extent. This is especially true in industry-impacted landscapes, where toxic metals in surficial peat can be elevated well above natural concentrations. Despite peatlands acting as contaminant sinks that can maintain their carbon storage functionality under low metal concentrations, high rates of metal pollution can lead to the degradation of peatland processes that sustain carbon sequestration. For example, the loss of keystone peatland species, such as Sphagnum mosses, limits peat accumulation and long-term carbon accumulation. Therefore, in these degraded peatlands, peat forming processes are often suppressed even decades after the source of contamination has reduced or ceased.
Once degraded, peatlands become susceptible to additional disturbances such as fire or erosion, which can release their toxic legacy into the environment and drinking water. Predicted future warmer and drier conditions are expected to increase wildfire prevalence on the landscape and may be further compounded by land use change. The release of previously sequestered metals arguably represents one of the largest contemporary global environmental disasters and greatest future global environmental challenge.
In this paper, we present an in-depth review of existing literature on ombrotrophic peatland metal contamination from a range of disciplines. After a detailed search and screening process, data were extracted from 97 studies. 500 individual points covering 26 countries were extracted from these studies, which were published between 1973 to 2022. For each study, the depth at which maximum heavy metal concentration (Cmax) occurred was recorded, along with surface concentration and concentration at depth. Using Kernel Density Estimates, the distribution of Cmax was typically within the top 0.2m of the peat surface across all studies, though with variation in the mean depth profiles between different metals. For example, Cmax for Cd and Zn typically peaked at 0.1m below the surface with few studies showing Cmax below 0.2m. As, Cu and Pb also had mean Cmax values <0.2m depth but showed a tail of Cmax values extending to at least 0.5m depth.
The review provides much needed understanding of the spatial extent of peatland contamination as an essential first step in tackling contaminant release from peatland fires. By quantifying the extent of heavy metals at depth in the peat profile, this work can link with peat fire modellers, ecohydrologists and climate scientists to better predict the impact of severe fires under future climate and land use change.
How to cite: Shuttleworth, E., Johnston, A., Clay, G., Mair, T., Waddington, M., McCarter, C., Basiliko, N., Gunn, J., Beckett, P., Byrne, K., Swindles, G., and Fewster, R.: Understanding the potential for disturbance-induced contaminant release from degraded peatlands: a global review of heavy metals in peatlands, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13582, https://doi.org/10.5194/egusphere-egu25-13582, 2025.
Peatland ecosystems, while covering only ~3% of the land surface area, are globally-important sinks of atmospheric carbon dioxide and regionally-important sinks of pollutants such as toxic metals and metalloids. While metal concentrations in peatlands are generally low, concentrations can be far higher near current and historic industrial centres, particularly in the upper few decimetres of the peat profile. Under normal conditions these metals remain safely sequestered in the peat. However, there is concern that, in addition to direct carbon emissions, peatland wildfires could represent a major pathway for metal mobilization and transport. Moreover, peat fires are dominated by smouldering, which is a low temperature combustion that leads to high concentrations of particulate matter within the smoke, representing a major health risk for communities impacted by wildfire smoke plumes.
With projected future climate change, annual area burned and subsequent carbon emissions are expected to rise, with drastic increases associated with high climate-forcing scenarios. In addition to greater area burned, higher evaporative losses associated with warming conditions may lead to increased peat smouldering vulnerability during wildfire. However, differences in local climate, projected changes in precipitation, and peatland type may have strong regionally-dependent mitigating effects.
Using the MODIS burned area product, we first develop an empirical relationship between current average area burned and regional climate. Using the climate-driven relationship, we estimate future changes in area burned from multiple climate models (CMIP6 GCMs) and across several climate-forcing scenarios (SSP 2-4.5, 3-7.0,and 5-8.5). In addition to changes in area burned, peat smouldering carbon loss is evaluated by simulating peat moisture profiles using HYDRUS-1D within a phase-space defined by evaporative demand and water table (WT) position. Under contemporary conditions, peat smouldering loss is concordant with the depth of peat that exceeds a critical soil water tension threshold under steady state conditions using the mean WT position. The impacts of climate change on smouldering carbon loss is then estimated based on the change in position within the evaporative demand–WT phase space. Peatland WT sensitivity to temperature and precipitation are taken from the literature and used to estimate changes in WT based on GCM projections across SSPs. Combined with published data on peatland type and location, we produce some of the first ever hemisphere-wide estimates of northern peatland carbon loss from smouldering due to climate change.
These spatially explicit results are used to highlight regions of overlap between increased burn area and severity with areas of high peat metal contamination. Taken together with estimates of particulate emissions from smouldering combustion, we provide an estimate of how climate change may increase global particulate matter emissions from northern peatlands. Moreover, uncertainty in the empirical relation and inter-model variability are used to quantify the confidence intervals for both projected area burned, peat burn severity, and thus particulate matter emissions, in order to highlight where future efforts are best focused for improving robustness of future projections.
How to cite: Moore, P., McCarter, C. P. R., Sutton, O., and Waddington, J.: Northern peatlands under fire: Projecting smouldering combustion loss in an uncertain future with implications for atmospheric metal emissions, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11827, https://doi.org/10.5194/egusphere-egu25-11827, 2025.
This study examined the impact of different water management (WM) strategies and farming practices on greenhouse gas (GHG) emissions from organic soils at two sites in Southern Germany—the Altbayerisches Donaumoos and the Freisinger Moos. The aim was to assess whether specific WM and land-use measures could stabilize water tables and reduce CO2, CH4, and N2O emissions, while maintaining agricultural productivity.
In our test site in the Altbayerisches Donaumoos (arable land growing grain maize under conventional and organic management), four field treatments were established: two with controlled WM via subsurface irrigation and two reference sites without active WM. Results from 2022 showed reduced total GHG emissions—mainly driven by lower CO2 and N2O fluxes—on the WM plots compared to references, especially under organic management. CH4 fluxes were negligible, indicating a minor effect on the overall budget.
In the test site Freisinger Moos (grassland with three cuts per year), four treatments (two with subsurface irrigation at 30 and 50 cm depth, one with a simple raised water table through a weir, and one “pipe-less” subsurface system) were monitored during 2022 and 2023. Despite generally higher water tables in the irrigated plots, both CO2 and N2O emissions remained substantial. The 50 cm subsurface irrigation consistently showed the highest GHG fluxes, partly due to more intensive management and greater biomass exports. Notably, all treatments displayed increased emissions in 2023 compared to 2022—a rise attributed to possible changes in water availability, climatic factors, and residual effects of organic fertilization.
These findings highlight the complexity of balancing water management, agriculture, and climate protection in peatland regions. While raising the water table can reduce peat decomposition, achieving significant mitigation requires careful consideration of fertilizer inputs, crop type, and long-term soil conditions. While water management did have an effect on reducing CO2 emissions, this is not yet sufficient to be seen as a climate friendly practice. Future research should address long-term impacts and refine water-level targets to further optimize land use on organic soils and mitigate associated greenhouse gas emissions.
How to cite: Lenz, D., Schlaipfer, M., Meyer, H., Gutermuth, S., Jörg, L., Ludwig, R., and Drösler, M.: Influence of water management on GHG-balances along a land use intensity gradient in fen peatlands , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11079, https://doi.org/10.5194/egusphere-egu25-11079, 2025.
Drained peatlands under intensive agricultural land use are hotspots of greenhouse gas (GHG) emissions. While management intensity and soil water status have been identified as major controlling factors, only few studies focussed on temporal dynamics and the contribution of nitrous oxide (N2O) and methane (CH4) to full annual GHG balances, mainly due to the lack of continuous observations in high temporal resolution. We present four years of parallel eddy-covariance (EC) and chamber GHG measurements at an intensively managed grassland site on bog peat soil. The site (DE-Okd) is part of the Integrated Carbon Observation System (ICOS) and represents common agricultural practice in Northwest Germany.
Average N2O fluxes measured by EC were consistently higher than those obtained by chambers. Following a grassland renewal, vegetation development in chamber frames was found to be more favourable than the average growth on the entire field that is seen by the EC tower. Poor grass development was identified by vegetation indices from remote sensing data and probably led to nitrogen surplus in the soil as observed by high ammonium and nitrate concentrations in drainage ditches. These conditions likely favoured both high N2O emissions and simultaneously high rates of nitrogen leaching. While N2O emissions made up considerable fractions of full annual GHG balances (~5 to 31%), the contribution of CH4 was negligible with hardly any significant fluxes detected by chambers and both seasonally varying emissions and uptake measured by EC cancelling out to non-significant shares to the overall budget.
N2O and CH4 emissions were strongly influenced by biometeorological factors and land management. Highest N2O peaks were observed two days after fertilizer application coinciding with about one week after grass cutting and highlighting a well-chosen chamber sampling scheme after management events. Further, N2O emissions were elevated during daytime under medium soil moisture and high soil temperature regimes, while CH4 emissions were strongly correlated with soil moisture dropping to nearly zero exchange under dry conditions.
Based on chamber measurements, the overall GHG balance of the site including harvest and carbon input through organic fertilization was in the range of 20 to 25 t CO2-equivalents ha-1 yr-1 in the period from 2020 to 2023 with generally higher emissions in dryer years. Replacing chamber N2O and CH4 by EC data for the full budget, individual annual values increased between 0.8 and 10.1 t CO2-equivalents ha-1 yr-1.
We conclude that the combination of EC and chamber measurements helped identifying temporal dynamics of GHG exchange for a better understanding of ecosystem functioning and quantifying method-based uncertainties. Conventionally managed grassland on drained peat soils with high fertilizer input and 4 to 5 grass cuts per year proved to be a significant net GHG emission source. Accounting for footprint heterogeneity – for example through adequate positioning of chamber frames – is of utmost importance for robust determination of total GHG balances at site-level scale.
How to cite: Lang, T. T. M., Tiemeyer, B., Wintjen, P., Düvel, D., Rüffer, J. J., Offermanns, L., Dettmann, U., and Brümmer, C.: Seasonal conditions and flux footprints control the contribution of N2O and CH4 to the full GHG balance at grassland on peat soil, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10958, https://doi.org/10.5194/egusphere-egu25-10958, 2025.
Up to 40% of U.K. grown vegetables are produced on lowland peat. This land use type is the highest emitter of carbon per unit area in the U.K., with drained agriculture on peatlands representing 3% of reported national greenhouse gas (GHG) emissions. This land use type impacts many other ecosystems service including the loss of topsoil and compaction, increased flood risk and biodiversity. However, total agricultural production from lowland peat equates to £1.23 billion in U.K. revenue providing income to farmers and jobs in the local area. Paludiculture and wetter farming are increasingly being considered as more sustainable alternatives to conventional farming to enable the continued productive use of peatlands whilst mitigating the impacts of peatland cultivation. Whilst there are several trials considering various paludiculture crops, there is a gap in the research which focuses on food crops in the U.K. We present the preliminary findings of a three-year wetter farming experiment focused on food crops in which carbon dioxide (CO2) and methane (CH4) emissions were measured from three agricultural lowland peat bog (ALPB) sites in the Northwest of England. The wetter farming experimental site in Greater Manchester was rewetted in March 2022. Celery (2022, 2023 and 2024) and lettuce (2024) crops were grown at a higher water table with annual averages of between 30.5 cm and 38.8 cm below the soil surface. The other two sites represented business as usual (BaU) drainage agriculture on ALPB with annual average water table depths between 69.1 cm and 96.2 cm below the soil surface. Both BaU sites are situated in Lancashire; one is a vegetable farm at which celery (2022, 2023 and 2024) and lettuce (2024) crops were monitored, the other farm is cereal farm where wheat fields were monitored (2022 and 2023). CO2 and CH4 emissions factors for the cultivation of these crops at various water table depths will be presented. In addition, we will discuss the impacts of specific farming activities (ploughing/cultivation, planting, fertilizer application and harvest) on CO2 and CH4 emission at all three sites. These emissions will be linked to both soil chemistry and physical attributes.
How to cite: Nolan, M., Longden, M., Hoskins, R., Andrews, L., Adams, A., Checkland, S., and Evers, S.: Food on Peat: The impact of wetter farming practices on greenhouse gas emissions from food crops on agricultural lowland peat bogs in the Northwest of England., EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18465, https://doi.org/10.5194/egusphere-egu25-18465, 2025.
The UK’s lowland peatlands occupy ~465,000 ha and are distributed across much of the country. The large majority (90%) of this lowland peat has been drained for agriculture, creating productive, fertile soils, but also exposing previously waterlogged organic matter to decomposition. Peatland drainage can alter aquatic biogeochemistry by increasing dissolved organic carbon fluxes to surface waters and promoting greenhouse gas (GHG) emissions from drainage ditches. Peatland rewetting has been demonstrated as an efficient mitigation technique for peatland GHG emissions. It is critical to understand how peatland drainage and subsequent rewetting may influence GHG emissions, as drainage may have allowed long-term accumulation of substances of agricultural or industrial origins, such as macronutrients (e.g. carbon, nitrogen, phosphorous) and heavy metals, which are released upon rewetting. Here, we present the results of an on-going, national-scale field study (part of the LowlandPeat3 project, https://lowlandpeat.ceh.ac.uk/lowlandpeat3) examining the spatio-temporal dynamics of GHG emissions in ditches draining arable lands (including conventional and regenerative agriculture) at paired “business as usual” and rewetted sites, during the baseline period prior to rewetting. We have measured carbon dioxide, methane, and nitrous oxide concentrations (and modelled fluxes) approximately monthly from sites across England. The results of this research will help us understand the risks and benefits of peatland rewetting on water quality, drinking water, aquatic ecology, and climate, to help inform lowland peat management and policy.
How to cite: Silverthorn, T., Andrews, L., Baker, F., Baugh, L., Bell, C., Chiverrell, R., Cumming, A., Evans, C. D., Evers, S., Flint, L., Holman, I., Jovani, J., McKenzie, R., Monsen-Elvik, E., Southon, F., Thenga, H., and Peacock, M.: Land management effects on ditch greenhouse gas dynamics in UK lowland peatlands , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8601, https://doi.org/10.5194/egusphere-egu25-8601, 2025.
Large areas of peatlands have been drained for agricultural and forestry purposes due to human activities. This drainage disrupts the natural hydrology of peatlands, leading to increased peat decomposition and turning these ecosystems into significant sources of greenhouse gas (GHG) emissions. Since the 1930s, extensive peatland areas in northern Norway have been drained and converted to agricultural land. To mitigate GHG emissions while maintaining biomass production, various management practices, including rewetting, are being promoted for these peatlands. Nevertheless, the impact of these mitigation measures on the peatland GHG balance remains largely unexplored.
We investigated grass productivity and the GHG balance in response to peatland cultivation under varying fertilization and hydrological treatments at a site in northern Norway. GHG fluxes (CO₂, CH₄, and N₂O) were measured using 30 automatic chambers at sub-daily intervals during the growing seasons of 2022-2024.
High water levels inhibited CO₂ emissions by suppressing ecosystem respiration, converting the ecosystem from a substantial CO₂ source to a sink or neutral state. Conversely, high water levels enhanced CH₄ emissions, while low water level plots remained CH₄ neutral. Sporadic N₂O emissions were observed to be higher under the more intensive fertilization regimen. Our results further highlight the critical role of harvest in determining the overall GHG and carbon balance in the ecosystem. This study has significant implications for guiding sustainable peatland management in Arctic regions.
How to cite: Zhao, J., Mastepanov, M., Klutsch, C., Silvennoinen, H., Kniha, D., Wara, S., and Kjær, R.: Can peatlands be used sustainably for agriculture in the Arctic Norway?, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9025, https://doi.org/10.5194/egusphere-egu25-9025, 2025.
Peatlands store around 30% of the world's soil organic carbon and therefore play a significant part in mitigating greenhouse gas (GHG) emissions. Some peatlands have been converted to agricultural use through artificial drainage and farming practices,leading to the accelerated release of carbon from the land to the atmosphere. However, the combination of soil characteristics, hydraulic properties and field management operations all play an important role in determining how much GHGs are emitted from the agricultural sites. The aim of this study is to 1) evaluate the applicability of the LandscapeDNDC model to cultivated peatlands by comparing the simulation outputs with the corresponding observations in the study site, and 2) assess the effects of the water table changes on GHG emissions. The LandscapeDNDC is a process-based model that can handle carbon and nitrogen cycling. The model can incorporate various input data, such as management, meteorological and water table data, and therefore provides a well-rounded framework for studying the effect of manipulating these input data on GHG emissions.
We performed the study at Luke Ruukki Research Station on the NorPeat platform, divided into 6 separate drainage blocks with varying peat depths (20 - 80 cm). Continuous flux measurements (June 2019 onwards) were collected at the site as well as block-specific dark chamber measurements of CO2 and N2O emissions. Each of the blocks had groundwater pipes equipped with pressure sensors to continuously measure the water table level. In addition, intensive measurements of soil properties and yield were carried out on the site during the study years 2019 - 2022, allowing us to establish a realistic site profile for our simulation runs.
The simulations were first validated with two meters: the satellite measurements of leaf area index and measurements of soil moisture. The model reproduced the observed variability in all blocks for both meters (R2 > 0.5) and was sufficiently able to simulate the observed CO2 and N2O fluxes. After analysing and ensuring that the model was able to reproduce the biochemical and hydraulic dynamics observed in the study site, we studied the three different water table scenarios and their effects on the GHG fluxes. In the scenarios the water table was raised on average to 15, 30, and 50 cm below the soil surface. These water table changes altered the soil respiration and nitrogen cycling, and provided insight into how peat thickness affects emissions. In addition, the study helped to quantify the mitigation effect of the raised water table, relieving the potential that water management could have on controlling GHG emissions.
How to cite: Kajasilta, H., Niiranen, M., Läpikivi, M., Liimatainen, M., Gerin, S., Kraus, D., Kulmala, L., Liski, J., and Vira, J.: The effect of water table depth on GHG emissions in an agricultural peatland with varying peat depth, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12529, https://doi.org/10.5194/egusphere-egu25-12529, 2025.
The majority of NW European peatlands are degraded due to management associated with conventional livestock farming (i.e. increased drainage, high nutrient inputs and frequent mowing). This leads to increased CO2 emissions, eutrophication, land subsidence, and biodiversity loss. Creating regenerative ditch borders along the drainage ditches that surround agricultural fields could locally ameliorate some of these negative effects. We investigated the impacts of implementing regenerative ditch borders on carabid beetle and plant diversity, soil characteristics, litter decomposition (Tea Bag Index (TBI) and leaf and root litter bags), and CO2 emissions in a Dutch fen agroecosystem throughout one year. On average we found lower numbers of carabid beetles in regenerative ditch borders, but a higher presence of specialist species. Species diversity remained unaffected by ditch border type. Plant diversity was higher in regenerative ditch borders. We also measured a clear shift in the dominant plant species between ditch border types, shifting from Lolium perenne in conventional borders to Phragmites australis in regenerative borders. Regenerative ditch borders were associated with higher values of soil moisture, soil organic matter content and carbon-to-nitrogen ratio and lower bulk density and soil compaction in comparison to conventional borders. The decomposition rate of standardized litter (TBI) was unaffected by ditch border type, but local leaf litter collected from regenerative borders (P. australis leaves) decomposed 75% slower than leaf litter from conventional borders (L. perenne leaves). Thus, litter decomposition between ditch border management types was driven by lower litter quality of aboveground litter produced at regenerative borders, and not by changes in soil characteristics (e.g. higher moisture levels). Nevertheless, projections from a locally-calibrated soil respiration model estimates that soil moisture effects significantly reduced CO2 emissions from regenerative borders compared to conventionally managed sites. Changes in vegetation composition and microenvironmental conditions resulting from regenerative management can therefore be expected to increase carbon storage and reduced peat respiration rates in ditch borders. This study highlights the importance of combining vegetation shifts with emission mitigation measures from peat agroecosystems and identifies possible trade-offs between biodiversity conservation and ecosystem services.
How to cite: Bethe, S., Berg, M., Hefting, M., and Weedon, J.: Biodiversity, decomposition, and CO2 emissions effects after the implementation of regenerative ditch borders in a Dutch peat agroecosystem, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19664, https://doi.org/10.5194/egusphere-egu25-19664, 2025.
Posters on site: Mon, 28 Apr, 16:15–18:00 | Hall X1
Raised bogs in Northern Germany face severe threats from drainage and land use, with more than half having been converted to grasslands and contributing significantly to greenhouse gas emissions. Restoring these ecosystems is crucial for achieving climate goals, such as those set by the Paris Agreement. While bog restoration following peat extraction is well-studied, efforts to restore nutrient-enriched agricultural areas into low-maintenance, self-regulating bog ecosystems are still in their infancy.
As a first step in raised bog restoration projects, topsoil is removed to prepare water-retaining polders. Due to previous agricultural use that did not involve peat extraction, substantial layers of weakly decomposed peat often remain intact. Their water-holding capacity can effectively buffer water table fluctuations, favoring peat moss (Sphagnum) establishment after rewetting. Meanwhile, nutrient legacies from agricultural use and competition from grassland and herb species may prevent the rapid re-establishment of peat mosses.
We found that when restoration areas are located near peat moss refugia, rapid and spontaneous colonization of polders with Sphagna can occur within two years of restoration, while other polders remain free of Sphagnum. This variability presents both opportunities, such as allowing rapid natural and low-effort restoration, and challenges, particularly in planning additional restoration measures (e.g. active introduction of bog species) to account for less favorable initial conditions within a site. In the OptiMuM project, we aim to understand these initial conditions better and focus on developing the best approaches for restoring raised bog habitats on former drained bog grasslands. We investigated the site-specific biotic and abiotic factors that influence spontaneous Sphagnum propagation in former grasslands and aim to identify optimal conditions for moss establishment. Additionally, we examine the emerging composition of Sphagna, their ecological value for raised-bog restoration, and the long-term benefits of these emerging ecosystems.
How to cite: Kunle, M., Wieseler, K., Huth, V., Beckert, M., Jurasinski, G., Günther, A., and Jansen, F.: Harnessing spontaneous colonization processes for raised-bog restoration: Case studies from the OptiMuM project, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17851, https://doi.org/10.5194/egusphere-egu25-17851, 2025.
The role of alternative terminal electron acceptors in peatland restoration.
Emily Fearns-Nicol, Catherine Hirst, Julia Knapp, Fred Worrall
Department of Earth Sciences, Durham University, Science Laboratories, South Road, Durham, DH1 3LE, UK.
The existence of peatlands relies on the balance of primary productivity and oxidation of organic matter. Oxidation requires a terminal electron acceptor (TEA). The most energetically favourable TEA is O2 followed, in order of reducing energy return, by NO3, Mn, Fe, and SO4. Organic matter itself can become a TEA with the production of methane (CH4). Organic matter will degrade faster the better access to the more energetically favourable TEAs. Therefore, the fate of the organic matter turnover in peatlands is related to the supply of TEAs. We hypothesize that if the supply of TEAs can be limited, then more organic matter could be preserved, and so enhance carbon sinks. Typically, water tables are raised to limit the access of TEAs into the peat porewater, however, it is not only high water tables that are required but also stagnant water tables otherwise fresh TEAs are brought into the porewater.
Bunds are used in peatlands to manipulate the water table to create environments for peat-forming species such as sphagnum mosses. However, bunds may also create areas of high and stable water table, and therefore allowing us to test our hypothesis. To test the hypothesis that stagnant water tables control organic matter storage, this study considered a peat covered hillslope where bunds had been installed. Monthly monitoring of these bunds, started in January 2024 and is being undertaken for soil water chemistry (pH, conductivity, absorbance, DOC, cations, anions), CO2 gas fluxes and water table depth. The site enables us to consider 9 bunded plots, alongside 9 control plots, with each plot having monitoring upslope, within and downslope of the bund.
There was a significant difference in ecosystem exchange down the hillslope, but no difference within individual bunds. Ecosystem respiration showed no signifncnat difference down the hillslope or relative to the individual bunds. There was a significant difference in absorbance and DOC down the hillslope, but no difference relative to the individual bunds. Equally, there was no significant difference in iron or sulphate concentration down the hillslope or relative to the individual bunds. Water tables were not significantly changed by the presence of the bunds nor was conductivity. In this blanket bog we are seeing that high water tables and swift transport pathways persist despite the presence of multiple bunds.
How to cite: Fearns-Nicol, E., Hirst, C., Knapp, J., and Worrall, F.: The role of terminal electron acceptors in peatland restoration., EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-825, https://doi.org/10.5194/egusphere-egu25-825, 2025.
Peat and other organic soils store large amounts of soil organic matter, which is highly vulnerable to drainage. Thus, drained organic soils contribute around 7% to the total German greenhouse gas (GHG) emissions and around 44% to the emissions from agriculture and agriculturally used soils, despite covering less than 7% of agricultural area in Germany. With approx. 90% of the total emissions, carbon dioxide (CO2) is the most important GHG with regards to drained organic soils. To evaluate possible GHG mitigation measures such as classical re-wetting, paludiculture or adjusted water management compared to the still widespread status quo of drainage-based peatland agriculture, an improved data set on GHG emissions, in particular CO2, and their drivers is needed. Furthermore, spatial data and upscaling methods need to be improved.
To meet these needs, a long-term monitoring programme for organic soils is currently (2020-2025) being set up for open land at the Thünen Institute of Climate-Smart Agriculture. A consistent long-term monitoring of soil surface motions, representatively covering a broad range of organic soil and land use types is combined with the repeated measurement of soil organic carbon (SOC) stocks to assess CO2 emissions using standardized and peat-specific methods. Land use types comprise grassland, arable land, paludiculture as well as unutilized re-wetted, degraded and semi-natural peatlands. At each of the envisaged approx. 130 monitoring sites important parameters such as groundwater table, vegetation and soil properties are monitored. Together with the updated map of organic soils and a revised machine learning model for water levels, all collected data form the basis for improving regionalisation approaches for drivers – particularly water levels and SOC stocks – and CO2 emissions from organic soils in Germany. Here, we will present the current status of site establishment with a focus on exemplary sites with water management.
How to cite: Tiemeyer, B. and the MoMoK-Team: Establishment of a German peatland monitoring programme for climate protection - Open land (MoMoK), EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15973, https://doi.org/10.5194/egusphere-egu25-15973, 2025.
Most peatlands and other carbon-rich soils in Germany are drained and responsible for 7% of national greenhouse gas (GHG) emissions. Peatlands used for agriculture account for 43 million tonnes of CO2 equivalents per year, or 80% of these emissions. Rewetting such areas would be an effective strategy to reduce their GHG emissions. This does not mean that productive land use has to be abandoned, as plants grown on rewetted peatlands can be used for many purposes, e.g. as horticultural substrates, building materials and bioplastics. However, the implementation of so-called paludiculture is still limited to small-scale projects as it poses many challenges for farmers, including complex authorisation procedures, high installation and maintenance costs, limited management expertise and the lack of established value chains for the biomass produced.
To support the transition to paludiculture, the German government is funding ten large-scale, long-term projects across different peatland regions of the country. The shared goal of these projects is to implement on a practical scale all steps from the planning of rewetting to the establishment and management of paludiculture up to the processing and marketing of the products. The projects include scientific monitoring to assess the impact of paludiculture on GHG emissions, nutrient fluxes, biodiversity and other ecological parameters as well as on economic and socio-economic conditions. In order to obtain nationwide representative results, the studies accompanying the projects need to be carried out using comparable methods and the data must be analysed comprehensively. Therefore, these projects work together in a networked called “PaludiNetz”, established and coordinated by the project “PaludiZentrale”. A key element of the PaludiNetz are the thematic working groups which consist of members that are responsible for the respective topics in their projects. In the working groups methods are tested and defined, results discussed and syntheses planned and carried out. Here, we will present the project’s approach and describe the cooperation within the PaludiNetz and with other paludiculture initiatives.
How to cite: Minke, M., Tiemeyer, B., and Tanneberger, F.: PaludiZentrale - Coordination and networking of large projects to jointly answer key questions to paludiculture and develop recommendations for action, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13716, https://doi.org/10.5194/egusphere-egu25-13716, 2025.
The cultivation of Sphagnum mosses is being developed both as a commercial product and for the restoration of peatlands, for example, in peat extraction areas that have been removed from production. Understanding the factors influencing the growth of Sphagnum mosses, and especially those that promote it, plays a key role in intensive farming. It is also crucial that grown mosses are healthy and robust when transferred to sowing areas.
We planted Sphagnum papillosum capitula in small plastic mugs on top of peat collected from old peat extraction area. On top of the peat, we spread willow and birch biochar. Straw was spread on top of the mosses to even out the moisture conditions. The irrigation water came through holes in the bottom of the mugs and there were three different types of water: from a raised bog, spring and a mixture of these. The mugs were in a growth chamber under standard conditions for three months. Subsequently, the mosses were imaged using Pulse-Amplitude-Modulation (PAM) to detect photosynthetic activity. For mosses, length, number of capitulum and fresh and dry weight were measured separately from capitula and stems. The aim of the study was to investigate the effect of different biochars and irrigation water on the growth of S. papillosum.
The best growth results were achieved in mugs with added willow biochar (232 ± 30.1 g m -2). The growth of mosses was almost half that of mugs without added char (126 ± 27.9 g m -2). Birch biochar also promoted moss growth in length, weight and number of capitula. Different irrigation waters did not have a statistically significant effect on moss growth (paired t-test, t = -0.400, p = 0.697, df = 11). The PAM measurement results were interpreted using "healthy" pixels identified in the image. When comparing the number of pixels, willow char, birch char and control treatments differed significantly, and the control mugs had lower photosynthesis activity.
The experiment gave promising results on the development of Sphagnum farming and possible guidelines for what can be studied next in field experiments.
How to cite: Laatikainen, A., Lehikoinen, H., and Tahvanainen, T.: The effect of biochar in the growth of Sphagnum papillosum, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15022, https://doi.org/10.5194/egusphere-egu25-15022, 2025.
Microbial communities play a critical role in peatland ecosystems, and in determining whether they act as net sinks or sources of greenhouse gas (GHG) emissions to the atmosphere. Furthermore, microbial community composition responds to changes in water table and physicochemical conditions, which are also determinants of GHG emissions from peatlands. Land management practices can significantly impact the water table and soil physicochemical conditions, influencing soil microbial community composition and activity, and site specific GHG emissions. Our study aimed to elucidate the role of paludiculture (peat conserving land use) intensity and nitrogen concentration on microbial community composition and function, and in turn, the potential role of changing microbial communities on seasonal GHG emission dynamics. We investigated GHG emissions, as well as a range of site physicochemical parameters, from 14 different EU fen peatlands, located in Germany (6), Netherlands (4) and Poland (4), on a monthly basis over the course of two years. Additionally, seasonal peat samples over two depths (living surface or 0cm, and at ~ 15cm depth below surface) were analysed for microbial community composition and function. Sample sites were separated into two different categories: Typha sp. dominated sites (7 sites, assumed to be highly nitrogen contaminated) and Carex sp. dominated (7 sites, assumed to be moderately Nitrogen contaminated) sites, with each further separated into three different paludiculture intensities: Wet wilderness (6 sites), Low intensity Paludiculture (6 sites) and High intensity paludiculture (2 sites). Initial results suggest a close relationship between microbial community composition and the sample country, as well as hydrological and nutrient status of the site, with a potentially significant relationship between microbial community composition, their main functions, and specific GHG emissions. The findings of our study would help to better understand how different paludiculture practices may impact microbial communities and influence GHG emissions from differently managed paludiculture sites.
How to cite: Boodoo, K., Emsens, W.-J., Verbruggen, E., and Glatzel, S.: The influence of paludiculture intensity on peat microbial community composition and resulting greenhouse gas emissions from fen peatlands , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18895, https://doi.org/10.5194/egusphere-egu25-18895, 2025.
The ITMS (Integriertes Treibhausgas-Monitoring System) Sources and Sinks module of the long-term project funded by the German Federal Ministry of Education and Research develops modeling techniques to simulate greenhouse gas fluxes with high spatial and temporal resolution for Germany. The integration of existing experimental data from national and Bavarian projects with new measurements from natural, drained and rewetted peat soils in the MODELPEAT project enables the modification and improvement of the process-based model LandscapeDNDC to allow also the simulation of peatland GHG exchange. At the same time, empirical modeling approaches are optimized for detailed peatland GHG characterization. Comparative analyses of both approaches will highlight their respective strengths, weaknesses and uncertainties and will help to find the optimal strategy for GHG exchange modeling at regional and national scales. This work is crucial for the identification of emission hotspots and the development of effective mitigation strategies. The poster will provide an overview of the project and preliminary modeling results for several peatland sites in Bavaria, where detailed experimental observations spanning decades are available. It will facilitate an evaluation of the model´s performance in representing undisturbed, drained, and restored peatlands. These estimates will be compared with regional estimates derived using statistical approaches.
How to cite: Braumann, F., Blagodatskiy, S., Klatt, J., Friedrich, S., Scheer, C., Kiese, R., and Drösler, M.: Modeling of greenhouse gas emissions from peatlands in Germany: merging empirical and process-based model approaches, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16249, https://doi.org/10.5194/egusphere-egu25-16249, 2025.
Understanding the carbon (C) balance of forestry-drained peatlands is crucial for addressing climate change. Natural peatlands are significant C sinks; however, soil carbon is released back into the atmosphere after the drainage of these ecosystems. Existing studies often face spatial and temporal variability, as many studies have focused on specific management practices, localized conditions, or short time frames. This narrow scope hinders the generalization of findings across diverse regions and peatland ecosystems.
This study examines the C balance of hemiboreal drained peatland forests by analyzing C pools and fluxes across various ecosystem components, including soil, vegetation, litter and leaching. Four sites in Estonia were selected, representing two distinct forest types: a drained bog forest (DBF), dominated by Scots pine (Pinus sylvestris), and three transitional fen forest (DTFF) sites, dominated by downy birch (Betula pubescens), Norway spruce (Picea abies), and Scots pine (Pinus Sylvestris), respectively.
The field measurements were conducted over two years (July 2022 to June 2024). Soil heterotrophic respiration (Rhet) during the vegetation period was measured biweekly in trenched plots using an opaque dynamic chamber connected to a portable CO2 gas analyzer EGM-5. Gas samples of non-vegetation period Rhet and year-round soil methane (CH4) were collected biweekly using manual static chambers and analyzed with gas chromatography. Soil physical and environmental were continuously measured and recorded at 30-minute intervals using CR1000 data loggers. Soil chemistry was evaluated once during the study period. The leaching of dissolved organic carbon (DOC) was estimated using plate lysimeters installed in the soil at a depth of 40 cm in all the studied stands. Furthermore, above- and belowground biomass and annual production were estimated through field-based measurements and empirical modelling approaches to calculate each site’s C balance.
Preliminary results indicate that Rhet was, on average, significantly higher in DTFF sites than in DBF sites, with levels approximately twice as high and reaching their highest emissions in spruce- and birch-dominated stands. The soil of the DBF site was a net CH4 source, while the DTFF sites were net CH4 sinks. Rhet and CH4 fluxes were primarily influenced by water table depth and soil temperature, with the highest fluxes observed during the peak of snow-free seasons. Carbon accumulation in aboveground vegetation (trees and understory) and inputs through litter were highest in spruce- and pine-dominated DTFF sites and lowest in the DBF site. Carbon losses as DOC in water were highest in DTFF-spruce and DBF sites. Belowground biomass contributed to ecosystem productivity through C inputs from root exudates and production.
In this study, annual net ecosystem production (NEP) and soil carbon balance were estimated using the biometric method. Further investigations of soil C fluxes and their relationships with soil and environmental parameters will be investigated to identify variability across different ecosystem pools and determine the overall C sink or source strength of hemiboreal drained peatland forests.
How to cite: Kamil-Sardar, M., Ranniku, R., Truupõld, J., Ostonen, I., Rohula-Okunev, G., Uri, V., Aun, K., Mander, Ü., and Soosaar, K.: Carbon Balance in Drained Hemiboreal Peatland Forests , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17220, https://doi.org/10.5194/egusphere-egu25-17220, 2025.
Drained peatlands are a strong source of greenhouse gas emissions. Peatland rewetting projects that aim to return sites to their near-natural state may collide with the need for land use in an agricultural or alternative way. The installation of ground-mounted photovoltaic systems might be an economically attractive use option for rewetted peatlands, beside the utilisation with paludiculture - i.e. agriculture and forestry on wet peatlands. In the project Moor-PV we investigate the impact of photovoltaic systems (solar panels) in rewetted peatlands on biodiversity, peat conservation as well as the water and climate balances. For the latter we measure fluxes of the three most important greenhouse gases (carbon dioxide, methane and nitrous oxide) under and outside the rows of bifacial solar panels to estimate annual balances at two different solar parks east and west of a railway line. Once preliminary gas flux data are analyzed, the impact of solar panels on the microclimate and their shading effect as a driver for potentially altered vegetation growth will be investigated. Our results will help to foster our understanding of the greenhouse gas exchange in this specific environment and to inform solar park operators and farmers about climate friendly use options on rewetted peatlands.
How to cite: Gutekunst, C., Hohlbein, M., Martens, H. R., Pump, C., and Jurasinski, G.: Effect of solar panels on greenhouse gas emissions in a rewetted peatland, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13231, https://doi.org/10.5194/egusphere-egu25-13231, 2025.
In the UK, ~420,000 hectares of agricultural land is situated upon lowland peat, representing around 2.5 % of the total agricultural land area. These sites disproportionately contribute towards greenhouse gas emissions, accounting for ~3% of the UK’s annual reported CO₂-equivalent emissions. These emissions, in addition to rapid soil erosion in some lowland peatlands, highlight the need to implement sustainable land management practices that promote soil stability, enhance carbon retention, and reduce greenhouse gas emissions whilst supporting agricultural productivity in agriculturally managed lowland peatland. Few studies have explored the trade-offs between the environmental benefits of sustainable land practices and their potential effects upon farm businesses, and few studies have explored how such practices influence the biogeochemical processes driving greenhouse gas emissions, nutrient cycling, and soil carbon stability in these systems. To address these uncertainties, we are conducting a field-scale study at a farm in Tarleton, UK, formed of two adjacent fields: one managed under a ‘business-as-usual’ regime and the other undergoing rewetting. Here, we present an overview of our study and some preliminary results. Within each field, we will test the viability of various commercially available soil amendments within experimental plots. Over two growing seasons, we will monitor greenhouse gas fluxes (CO₂, CH₄, N₂O), soil and pore-water biogeochemistry and crop yields across the treatment plots. This will allow us to compare the environmental and economic outcomes of each treatment and to identify the biogeochemical processes underlying any observed changes. Our findings will inform UK land-use policy, offering evidence-based recommendations for reducing emissions from agricultural lowland peat whilst upholding soil integrity and food security. Our findings will also enhance our understanding of how different management changes affect biogeochemical processes within peatland soils. This study forms part of the Lowland Peat 3 Project, which will assess the environmental, economic, and social trade-offs of agricultural practices on lowland peatlands across the UK.
How to cite: Andrews, L., Nolan, M., Morrison, R., Bell, C., Evans, C., Monsen-Elvik, E., Riutta, T., and Evers, S.: Balancing Emissions, Productivity and Soil Health: Rewetting and Soil Amendments in a Cultivated Lowland Peatland in NW England, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18256, https://doi.org/10.5194/egusphere-egu25-18256, 2025.
In this work, the annual CO2 and N2O balance and analysis of the drivers for fertilized grassland on peat for a dairy farm under three groundwater level control options will be presented. This experiment is conducted in the context of the Dutch NOBV project (National Research program on GHG for peatland areas) as part of the Dutch Climate Agreement which has a chapter to reduce GHG emissions from peatland areas by 1 MtCO2-eq annually.
The groundwater level control options applied are the conventional ditch water level control system, nowadays often being replaced by drainage and ditch level control, and finally drainage and pressure control. Several fields of the Zegveld experimental farm are divided in three segments, each which a control option applied and a such allow study under comparable conditions.
Two years of GHG fluxes are reported and measured using one closed-path Aerodyne system switching inlet line each half hour using three small towers equipped with a Gill sonic anemometer at 1.75 m height in the middle of the largest elongated farm field. The eddy-covariance method was used to calculate half-hourly fluxes. The location and low measurement height maximize the representation of the field in the flux measured from all wind directions. CO2 fluxes showed uptake during the day and respiration during nighttime. After harvesting and grazing, emission fluxes prevailed. N2O peaks coincided well with agricultural management, e.g. grazing and fertilization, but also biometeorological factors like water temperature and ground water table influenced N2O emissions. From October 2023 to March 2024, N2O emissions were close to zero due to prolonged precipitation resulting in a shallow water level across all fields inhibiting production of N2O in the subsurface layer. Due to the high contribution of the field to the footprint compared to surrounding ditches, CH4 fluxes didn’t correlate with any in-field measured parameters driving the hypothesis that ditches appear to be the main source of CH4.
Flux loss corrections based on an empirical approach using measured ogives. Gap-filling of the N2O and CO2 fluxes was done using the gradient boosted regression trees XGBoost. The gap-filling process utilized a comprehensive set of predictors to enhance the accuracy and reliability of flux measurements. A comparison with an open-path CO2 system installed at one location showed a reasonable agreement with CO2 fluxes of the closed-path measurement system.
How to cite: Wintjen, P., Frumau, A., van den Bulk, P., van Mansom, H., and Hensen, A.: Groundwater level control as GHG emission reduction option tested using eddy covariance for peatland in the Netherlands, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12079, https://doi.org/10.5194/egusphere-egu25-12079, 2025.
Globally, millions of hectares of peatlands have been drained for agriculture and forestry by the digging of ditches, amounting to millions of kilometres of drainage ditches. It has been known for three decades that these ditches can be landscape-scale hotspots of the potent greenhouse gas (GHG) methane (CH4), as well as acting as sources of carbon dioxide (CO2) and nitrous oxide (N2O). Rewetted peatlands also feature remnant ditch networks that may be partially infilled or blocked, or still used for water management, and these waterbodies can continue to emit large amounts of GHGs.
Although a growing number of studies have measured and reported peatland ditch emissions, substantial knowledge gaps remain. Here, I will draw on my own research and that from the literature to give an overview of the importance that ditch emissions play in the GHG budgets of peatlands. This will include peatlands drained for forestry, grassland, and cropland, as well as rewetted peatlands. I will also highlight knowledge gaps and questions that remain to be answered about the role peatland ditches play in the carbon and GHG cycles.
How to cite: Peacock, M.: The importance of ditches in the greenhouse gas balances of managed and rewetted peatlands, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3205, https://doi.org/10.5194/egusphere-egu25-3205, 2025.
Pristine boreal peatlands store vast reserves of terrestrial carbon and have a net cooling impact on climate in the long term. Peatland drainage increases CO2 and N2O emissions and decreases CH4 emissions, leading to a net warming impact on climate. For example, cultivated peatlands can have high greenhouse gas (GHG) emissions per area and are therefore attractive targets for national aims to reduce GHG emissions. Raising water table depth (WTD) level can decrease the climate-warming impact. However, as drainage changes peat properties, the WTD elevation may lead to additional leaching of e.g. redox-sensitive phosphorus (P), which often restricts primary production in freshwaters. To support environmentally sound climate actions, we aimed to study the simultaneous impacts of different WTD conditions on GHG emissions and P leaching in variably managed peatlands.
Our study sites include cultivated peatland plots with different peat thicknesses, peatland forest, abandoned peat field, and pristine peatland. The chemical potential for P retention in different soil depths was studied using chemical extractions of soil. The GHG emissions in field conditions were studied with year-round GHG emission inventories, which were conducted with chamber methods in snow-free conditions and otherwise with the snow-gradient method. Besides the effect of WTD, also the effects of vegetation and several environmental variables were considered. The simultaneous effects of different WTD conditions (saturation, slowly lowering WTD, quick fluctuations) on GHG emissions and P leaching were studied using intact soil profiles with a column experiment in controlled conditions.
Our results help to find the best water management solutions considering both GHG emissions and P leaching. This knowledge is especially important in countries with large areas of drained peatlands and attempts to lower both GHG emissions and nutrient leaching. Sometimes land use changes may be unavoidable, and our studies with different land use options also support decision-making in these situations.
How to cite: Höyhtyä, I., Liimatainen, M., Tolvanen, A., Ronkanen, A.-K., Pham, T., Niiranen, M., Kujala, K., Läpikivi, M., Hyvärinen, M., Kløve, B., and Marttila, H.: The impacts of water table dynamics on greenhouse gas emissions and phosphorus leaching in managed boreal peatlands, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-4016, https://doi.org/10.5194/egusphere-egu25-4016, 2025.
The primary objectives of peatland restoration are to reduce greenhouse gas emissions and maintain water quality. However, the effects of human activities, such as drainage and rewetting, on pore water quality remain insufficiently understood. In this study, we synthesized pore water quality data from 197 northern peatlands, encompassing natural, drained, and rewetted systems. Our analysis revealed that drainage significantly increases the concentrations of dissolved organic carbon (DOC), ammonium, and phosphate in pore water compared to natural peatlands. While rewetting reduced these concentrations, they remained elevated relative to natural systems. Notably, pore water concentrations in rewetted peatlands were closely linked to water table levels, with peak concentrations observed under inundated conditions, particularly in fen peatlands. Over an approximately 30-year observation period, no consistent temporal trends in pore water quality following rewetting were identified. These findings highlight the complexity of pore water quality responses to rewetting and the importance of long-term monitoring for optimizing peatland restoration practices.
How to cite: Liu, H., Zak, D., Petersen, R. J., Rezanezhad, F., Fenner, N., and Lennartz, B.: Pore Water Quality in Northern Peatlands: Impacts of Drainage and Rewetting, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13237, https://doi.org/10.5194/egusphere-egu25-13237, 2025.
Coastal peatlands are vulnerable to environmental changes, including salinity fluctuations caused by storm surge-induced seawater intrusion. This study investigates ammonium (NH₄⁺) release patterns during simulated sea flooding event in two locations of a coastal peatland in Northeast Germany (Hütelmoor): a near-natural location and a historically drained and rewetted location. Undisturbed soil samples (N=18) were collected from two depths (0–10 cm and 30–40 cm) at each location. A leaching experiment was conducted using three salinity treatments (N=3): groundwater (control, <1 ppt), Baltic Sea water (10 ppt), and mean seawater salinity (35ppt). Soil hydro-physical properties were determined following leaching experiment.
Results showed that NH₄⁺ release varied with salinity, soil depth, and land management. In the topsoil (0–10 cm), both locations exhibited high NH₄⁺ release at <1 ppt initially; however, higher salinity treatments (10 ppt and 35 ppt) continued to release elevated NH₄⁺ over time. In the subsoil (30–40 cm), rewetted samples under 10 ppt salinity released the most NH₄⁺, highlighting them as hotspots for nutrient mobilization during Baltic Sea flooding events.
Soil hydro-physical properties varied significantly across locations and depths, with a notable negative correlation between NH₄⁺ release and both saturated hydraulic conductivity (Ks) and macroporosity. This correlation was primarily driven by subsoil samples. While differences in hydro-physical properties were evident between near-natural and rewetted topsoils, they did not significantly influence NH₄⁺ release, suggesting that other factors, like soil organic matter (SOM), may play a more critical role in topsoil NH₄⁺ dynamics. In the subsoil, near-natural peat, characterized by higher Ks and macroporosity, retained less NH₄⁺ and released smaller amounts. Conversely, the rewetted subsoil, with lower Ks and macroporosity, accumulated and released more NH₄⁺, identifying it as a hotspot for nutrient mobilization.
Overall, by examining how local variations in soil hydro-physical properties across different locations within a single site influence NH₄⁺ release, this research identifies key hotspots for nutrient mobilization in a rewetted peatland. The findings highlight the necessity of accounting for both spatial and vertical soil property variations in coastal peatland restoration and management, especially regarding the prediction of environmental risks associated with nutrient release. Future research should examine how biogeochemical processes and microbial activity interact with soil hydro-physical properties to influence nutrient dynamics, especially under changing climate scenarios.
*Note: The first and second authors contributed equally to this work and share first co-authorship.
How to cite: Wang, M., Liesirova, T., Liu, H., Voss, M., and Lennartz, B.: The influence of local variations in soil hydro-physical properties on ammonium release during flooding events in a coastal peatland, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9974, https://doi.org/10.5194/egusphere-egu25-9974, 2025.
The loss of carbon from peatlands occurs through gaseous emissions and a substantial fraction from aquatic fluxes, specifically dissolved organic carbon (DOC), during mineralisation and degradation processes. Our study hypothesises that DOC production is dependent on pore size, with higher concentrations occurring in finer pores. To investigate this, pore water was extracted at specific pressure heads (-60 and -600 hPa), representing macro- and mid-size pore domains, from degraded peat samples. Soil organic matter content was measured at 34 wt% in the topsoil and 57 wt% in the subsoil. Notably, the more degraded topsoil exhibited significantly higher average DOC concentrations than the subsoil, with levels 1.5 times greater at -60 hPa and 2.4 times higher at -600 hPa. These trends indicate that degraded peat soils are prone to release greater amounts of DOC. Additionally, DOC concentrations in topsoil samples were consistently higher at -600 hPa compared to -60 hPa.
The negative correlation between soil organic matter (SOM) and DOC at -600 hPa (r = - 0.53; p < 0.0001) aligns with degradation-driven reductions in SOM and porosity. Degraded topsoil exhibited high DOC variability for SOM < 40 wt%, stabilising below 50 mg/L for SOM ≥ 40 wt%. Through a graphical illustration, we infer that the elevated DOC export is likely due to the higher surface-to-volume ratio observed in mid-sized pores (-60 to -600 hPa), further enhanced by the dual-porosity structure of the degraded topsoil. This structural variation contributes to differences in carbon turnover rates. Additionally, microbial communities and their abundance differ across pore size classes, causing pore size-dependent reactions that influence DOC export.
How to cite: Cambinda, R., Lennartz, B., Liu, H., and Rezanezhad, F.: Impact of Pore-Size-Class on Carbon Turnover in Peat Soils, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13474, https://doi.org/10.5194/egusphere-egu25-13474, 2025.
Plant-available phosphorus (P) is the quantity of labile P that can be utilised by soil biota. This P pool is a major driver of plant growth, affecting the mineralisation of soil organic matter and the risk of P leaching. A common agronomic soil test (calcium-lactate extraction, PCAL) is regularly used to assess the status of plant-available nutrients in cultivated soils, while extraction with a bicarbonate-buffered dithionite solution (PDT) is suggested as a proxy for redox-sensitive P that might be released upon rewetting. However, systematic P studies on peat and other organic soils are scarce. The few studies that are available mostly describe P stocks over large depth increments or focus on leaching risks only. Organic soils are characterised by a high heterogeneity of the accumulated substrates and by a complex differentiation of the soil horizons. In addition, peatland management practices vary considerably from region to region, strongly influencing the level of water and nutrient management. Therefore, assessment of P status requires a specific soil sampling approach that reflects the genuine characteristic of organic soils and consider specific differences in peatland management. This is particularly relevant for paludiculture sites, where information is needed on both the beneficial and potentially harmful aspects of labile P (i.e. plant nutrition and risk of eutrophication). However, there are no agreed sampling and analysis methods especially for wet organic soils.
Here, we analyse data on the labile P pool (PCAL and PDT) from about 100 sites comprising more than 500 horizons of the German Peatland Monitoring Programme, covering a wide range of organic soils and land use types. In addition, data from a fen paludiculture project are used to elucidate spatial and temporal variability. These results will allow us to derive a baseline data set of the labile P pools in different organic soils depending on land use type, land use intensity and water management. Furthermore, appropriate sampling schemes will be derived specifically for paludiculture sites. Thus, the results can be used to contextualise specific (future) paludiculture site conditions with respect to biomass production and P leaching risks.
How to cite: Heller, S., Tiemeyer, B., Dettmann, U., Köwitsch, P.-F., Heidkamp, A., Kuwert, M., Laqua, S., Piayda, A., Schemschat, B., and Frank, S.: Labile phosphorus in peat and other organic soils: baseline data and sampling protocols for paludiculture , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12506, https://doi.org/10.5194/egusphere-egu25-12506, 2025.
Peatlands have been widely recognised as important carbon stores, ecological habitats and natural hydrological buffers. However, comparatively less attention has been given to the role of peatlands as long-term stores of pollutants, particularly toxic metals and metalloids (TMMs). Furthermore, the potential for their release is poorly understood. An improved understanding of TMM distribution and release in peatlands is critical, because climate warming risks increasing their mobilisation, through enhanced decomposition and changes to hydrological processes, with potentially significant implications for natural ecosystems and human health. The PIPES project (Pollutants In Peatlands: from sink to Source) aims to identify global “hot spots” of peatland pollutants and establish likely release mechanisms of currently inert TMMs. We use a unique combination of observational and controlled-experimental approaches to address two research questions: (1) What is the content and distribution of pollutants in global peatlands? and (2) Under what conditions, and through which pathways, are these pollutants most likely to be released? In this presentation, we share early findings from both components of the PIPES project. Firstly, we present our ongoing analysis of the distribution of TMMs in global peatlands, with a primarily focus on spatial patterns identified across our comprehensive network of sites in the UK and Ireland. We quantify the total content of TMMs using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) in peat cores compiled by a network of > 90 international collaborators. Secondly, we present preliminary results from controlled environmental simulations of TMM release in peat monoliths from subarctic Sweden. We explore both pore-water and atmospheric release under scenarios of drought, climate warming and a shallow burn. Our findings provide crucial new insights into the potential fate of pollutants in global peatlands and their implications for human health and natural ecosystems.
How to cite: Fewster, R., Swindles, G., Clay, G., Shuttleworth, E., Galloway, J., Gallego-Sala, A., Kelly, T., McCarter, C., Purdy, E., and Sloan, J. and the PIPES research group: Global stocks and release pathways of pollutants in peatlands, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-296, https://doi.org/10.5194/egusphere-egu25-296, 2025.
Sphagnum moss plays an important role in regulating toxic metal and metalloid mobility by influencing peatland pH, dissolved organic matter composition, and ecohydrology. However, historical toxic metal and metalloid pollution has led to the absence of Sphagnum moss peatlands in many landscapes globally. Other often co-occurring pollutants, like sulphate, alter peatland biogeochemistry, leading to enhanced peat decomposition and altering peatland pH, dissolved organic matter composition, and ecohydrology. Furthermore, in these polluted landscapes, toxic metals and metalloids are preferentially stored in organic soils relative to mineral soil ecosystems and peatlands are thought of as landscape sinks for these pollutants. As Sphagnum moss returns to these polluted peatlands, whether naturally or from peatland restoration activities, it is unknown whether these landscape stores of toxic metals and metalloids is at risk of mobilizing to sensitive downstream ecosystems.
During historical smelting operations in Sudbury, Ontario, Canada an estimated 12,000 t of copper and nickel were released to the atmosphere, most of which was deposited within 100 km of the smelters where peat concentrations can exceed 1000 mg kg-1. Here, we used a spatial gradient of peatlands at varying levels of impact (high, moderate, low, none) in the region surrounding Sudbury as a model for recovery over time to understand the potential mobilization of toxic metals and metalloids due to the return of Sphagnum moss. In peatlands with no Sphagnum recolonization, both copper and nickel (along with other toxic metals and metalloids like methylmercury and arsenic) pore water concentrations were elevated (> 10 µg L-1) relative to peatlands with higher Sphagnum moss cover and lower initial impacts. These conditions coincided with higher dissolved organic matter (DOM) concentrations and humification levels but divergent relationships between DOM humification and copper/nickel concentrations were observed. There was no clear trend in apparent partitioning coefficient with Sphagnum recovery, while pH was the highest in the most impacted peatlands (no Sphagnum recovery, pH ~4 - 5). In the surficial peat (i.e., the surface of moss recolonization, 0-10 cm), a decrease in pH was not correlated (p > 0.1) with either water extractable copper or nickel and the apparent partitioning coefficients of either metal. While, in deeper, lower hydraulic conductivity peat, (10-20 cm) only the copper apparent partitioning coefficient significantly (p < 0.0001) declined with decreasing pH, suggesting increased geochemical mobility but decreased ecohydrological mobility.
The combined results suggest that the return of Sphagnum moss does not necessarily increase the risk of historical toxic metal release due to the numerous hydrobiogeochemical feedbacks that operate in peat and peatlands. As such, promptly returning Sphagnum moss to these polluted peatlands is critical to mitigating the potential for catastrophic metal release due to wildfires and droughts.
How to cite: McCarter, C., Pawson, K., Mclean, C., and Emilson, E.: Does returning Sphagnum moss to toxic metal polluted peatlands increase aqueous metal mobility?, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10338, https://doi.org/10.5194/egusphere-egu25-10338, 2025.
Industrial contamination has profoundly impacted peatland ecosystems, degrading their biodiversity and essential functions such as carbon sequestration. The Sudbury region in Ontario, Canada is one of the world's largest metal mining centres and historically the largest global point source of sulfur and metal pollution and serves as a critical case study for understanding and addressing these impacts. Peatlands closest to pollution sources have suffered extensive degradation, with keystone vegetation, including Sphagnum mosses, locally extinct and peat layers showing significant carbon losses. Developing innovative restoration techniques is crucial before undertaking regional-scale restoration of metal-impacted peatlands, ensuring chemical stressors are overcome effectively while minimizing sequestered metal release. In collaboration with regional stakeholders and academic institutions, our interdisciplinary team is pioneering innovative restoration techniques to reinstate peatland functionality in this toxic metal and metalloid-polluted landscape. Building on established practices, such as the moss-layer transfer technique, our modified approaches incorporate surface tilling, mulching, fertilization, and the reintroduction of donor peatland material. These interventions aim to overcome chemical stressors like persistent high concentrations of water-extractable metals (e.g., copper and nickel), which inhibit Sphagnum recovery. A restoration field trial began in fall 2023 with surface mulching, and in spring 2024 we applied restoration treatments of mulch, fertilizer, and planting. Here, we present results from the first growing season for peat chemistry, hydrology, greenhouse gas fluxes, and vegetation.
How to cite: Goud, E., McCarter, C., Whittington, P., Basiliko, N., Beckett, P., Pendea, F., and Gunn, J.: Restoring metal contaminated peatlands in Sudbury, Ontario, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20039, https://doi.org/10.5194/egusphere-egu25-20039, 2025.
Posters virtual: Wed, 30 Apr, 14:00–15:45 | vPoster spot A
EGU25-2449 | Posters virtual | VPS4
Sorption Behavior of Rhamnolipid Biosurfactant on PeatWed, 30 Apr, 14:00–15:45 (CEST) | vPA.16
Surfactants are extensively utilized across agriculture, pharmaceuticals, and environmental remediation due to their ability to modify surface and interfacial properties. In horticulture, wetting agents and synthetic surfactants are commonly employed to mitigate water repellency in organic growing media, particularly peat-based substrates. These agents are known to aid the substrate’s wettability and improve physical and hydraulic properties, optimizing plant growth and productivity. However, environmental persistence and the potential ecotoxicity of synthetic surfactants have raised significant concerns, highlighting the need for sustainable alternatives. Biosurfactants, particularly rhamnolipids, have gained considerable attention for their biodegradability and surface-active properties both at the scientific and commercial levels. Despite their potential, a comprehensive understanding of the interaction between rhamnolipid and peat essential for assessing its environmental fate and behavior is inadequate. In this regard, the main objective of this study is to quantify the sorption and desorption dynamics of rhamnolipid in peat using batch equilibrium and kinetic experiments to evaluate its suitability as a surfactant for horticultural systems, optimize application strategies, and assess the transport behavior and environmental implications of residual surfactants. Kinetic analysis revealed rapid initial adsorption followed by a gradual approach to equilibrium, with the adsorption and desorption kinetics being well described by the Elovich equation, indicating a chemisorption-dominated process. Furthermore, desorption followed both the Elovich and pseudo-first-order models, illustrating a complex and rate-dependent release process likely influenced by heterogeneous retention of rhamnolipid on the peat surface. Equilibrium analysis demonstrated that the adsorption data were best fitted by the Freundlich model, reflecting the heterogeneous nature of the peat surface and the complexity of its adsorption sites. Sequential desorption experiments exhibited notable hysteresis with reduced desorption efficiency, suggesting strong retention of rhamnolipid on the peat particles. These findings highlight the potential of rhamnolipid as a sustainable alternative to synthetic surfactants for mitigating water repellency in peat-based growing media. Equilibrium and kinetic modeling results will be presented with a comprehensive discussion of their practical implications, providing critical insights into their environmental significance and potential applications in horticultural systems.
Keywords: Water repellant peat, sorption, rhamnolipid biosurfactant
How to cite: Duggireddy, R. and Arye, G.: Sorption Behavior of Rhamnolipid Biosurfactant on Peat, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-2449, https://doi.org/10.5194/egusphere-egu25-2449, 2025.
