Canada’s terrestrial ecosystems play a critical role in the global carbon cycle and are being affected by unprecedented climate change and wildfire disturbance. However, we have an incomplete understanding of Canada’s historical carbon cycle. Existing assessments, conducted at varying spatial scales, use a wide range of data sources and methodologies, which lead to significant differences in the estimated strength of Canada’s land carbon sink over recent decades. Moreover, many approaches (e.g., inversions and data-driven estimates) have a limited ability to disentangle the relative contributions of different processes to the carbon sink over the recent past (1700 - 2022). We addressed this gap using a land surface model recently tailored to Canada and the most comprehensive information depicting wildfire disturbance and timber harvest available to make, to our knowledge, the first physically coherent wall-to-wall estimates of all major carbon pools and fluxes for Canada. We show that Canada’s terrestrial ecosystems have been a carbon sink since the mid-20th-century, due to the influence of wildfire and timber harvest before 1940. Since the early 2000s, wildfire disturbance has been driving Canadian forests towards becoming a carbon source. Based on our findings from a purely process-oriented perspective, projected increases in wildfire activity will further impact the strength and direction of Canada's terrestrial carbon sink.

How to cite: Curasi, S., Melton, J., Humphreys, E., Arora, V., Beaver, J., Cannon, A., Chen, J., Hermosilla, T., Lee, S.-C., and Wulder, M.: Canada’s forests shifting from a recovery-driven carbon sink to a disturbance-driven carbon source, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-14857, https://doi.org/10.5194/egusphere-egu26-14857, 2026.

The attenuation of atrazine in the saline water of the hypersaline Pétrola lake from a natural reserve (SE Spain) was studied to get more insight into the processes governing the fate of the contaminant in highly saline environments. In microcosms, the water column was spiked with 15.4 mg/L of atrazine for 24 days. Before atrazine amendment, the initial distribution of bacterial community was mostly composed of Proteobacteria (25.5 %), Cyanobacteria (25.2 %), Actinobacteriota (18.5 %), Verrucomicrobiota (11.5 %) and Bacteroidota (10.1 %). Within the mayor phyla, the most abundant families were identified as Cyanobiaceae (25 %), Rhodobacteraceae (10 %), Alcaligenaceae (9.9 %), Microbacteriaceae (7.3 %) and a poorly described PeM15 (6.2 %).

The reduction of atrazine concentration in the water column reaches 86.9 %, which means a reduction of dissolved atrazine mass of 98.1 %. Parallel to the decrease in atrazine, the amount of its intermediate degradation metabolite, desethylatrazine, increased. Desethylatrazine was the major short-term metabolite within the first 8-12 days, indicating the potential activity by atrazine-degrading bacteria. No deisopropylatrazine was detected in the saline water above detection limit. Microbiology results showed that atrazine can be removed from the saline lake environment. After atrazine amendment, the taxonomic bacterial composition at phylum level shifted to Proteobacteria (60.8 %), Patescibacteria (9.7 %), Bacteroidota (7.3 %), Campylobacterota (6.4 %) and Actinobacteriota (2.1 %). Atrazine supplementation suggested a selective pressure on bacterial structure morphology through the emergence of different dominant groups (i.e., Campylobacterota) or even the eradication of those phyla of bacteria capable of photosynthesis (i.e., Cyanobacteria). At family level, Rhodobacteraceae (16.7 %), Burkholderiaceae (11.7 %), Thiomicrospiraceae (7.9 %), Methylophagaceae (6.7 %), Sulfurimonadaceae (4.4 %) and Solimonadaceae (3.3 %) were the most abundant in the water column at the end of the experiment.

Related atrazine-degrading families established at the end of the experiment were Rhodobacteraceae, Solimonadaceae, Pseudomonadaceae, Rhizobiaceae, Chromatiaceae, Bacillaceae, Xanthomonadaceae, Caulobacteraceae, Moraxellaceae, Streptomycetaceae, Microbacteriaceae and Nannocystaceae. Related candidates such as Pseudomonas paralactis, Microbacterium sp., or Arthrobacter sp., among others, were isolated in water samples from previous studies. The bacterial candidates for atrazine degradation identified in the water column indicate that the herbicide acted as a selective pressure factor, altering the composition of the bacterial pattern. The water column would constitute a reactive environment which may govern the fate of pesticides in saline surface water bodies.

How to cite: Espín Montoro, Y., Martínez Couque, G., Fernández Pérez, J. A., Álvarez Ortí, M., and Gómez Alday, J. J.: Selective pressure of atrazine on bacterial pattern in a hypersaline lake environment , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5322, https://doi.org/10.5194/egusphere-egu26-5322, 2026.

The EU Nature Restoration Regulation is the first continent-wide, comprehensive law of its kind and is a key component of the EU Biodiversity Strategy. This sets binding targets to restore degraded ecosystems, particularly those with the most potential to capture and store carbon and to prevent, and reduce, the impact of natural disasters. The EU Nature Restoration Regulation contains seven specific targets, including:

‘marine ecosystems – restoring marine habitats such as seagrass beds or sediment bottoms that deliver significant benefits, including for climate change mitigation…….’

The 800 hectares of seagrass meadows in South-West England are rightly regarded as important biodiversity ‘hot spots’, providing habitats for many species of juvenile fish, cuttlefish and sea horses. Many of the meadows in the region have been impacted by a ‘Seagrass Wasting Disease’ in the 1930s and the more recent damage caused by the anchoring of small boats (usually pleasure craft). This damage is being rectified by re-planting of seagrass, but many of those engaged in this work do not appreciate the full story behind the present distribution and development of the meadows.

The oldest seagrasses are known from the Maastrichtian of The Netherlands and are found in the Maastricht Chalk Formation (70 million years’ old). Between that time and the present day there are very few direct records of seagrass fossils, and this is because:

• Seagrass meadows from the tidal/inter-tidal boundary are not in an environment that is commonly preserved in the geological record; and
• In modern seagrass meadows, the plants are rarely – if ever – preserved and are rarely found in cores drilled into the meadows below ~30 cm.

In marine cores taken in Plymouth Sound and elsewhere in Southern England there are only low levels of carbon (spores, pollen, dinoflagellates, seeds, and organic debris) and not the high levels that would be required to suggest that sea grasses sequester high levels of ‘blue carbon’ for extended periods of time. The accumulation of low carbon levels can be explained by the enhanced sedimentation created by the seagrass, the so-called allochthonous carbon. The one element of carbon sequestration that is often ignored is that of foraminifera, ostracods and bryozoans, all of which are extremely abundant in meadow sediments. In many cases, the biodiversity of the foraminifera (>100 species) dwarfs the usual biodiversity counts of larger organisms. Such fixed calcium carbonate does have a long-term storage potential.

The other issue that can be ignored by those studying seagrasses is that the marine environment has undergone significant change throughout the 1 million years of the Pleistocene/Holocene and many of the seagrass meadows have only just re-established themselves following the Last Glacial Maximum, when sea levels were 120‒130 m below present-day levels. How seagrass migrated back into the present-day coastal areas is not yet fully understood, including the separation of the inter-tidal and sub-tidal taxa.

How to cite: Hart, M. and Fisher, J.: South-West England seagrasses: ecology, evolution and contribution to biodiversity and carbon sequestration , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-4468, https://doi.org/10.5194/egusphere-egu26-4468, 2026.

Microorganisms in estuarine and coastal ecosystems are subject to changes in salinity and nutrient loads as well as threats from emerging contaminants, sea level rise, extreme weather patterns, and human encroachment. These ecosystems are of economic and ecological importance due to their biological diversity as well as their role in carbon sequestration, flood protection, and erosion prevention. However, the microbial community structure in the sediment of estuarine systems remains under researched despite the abundant ecosystem services they provide. In this study, we surveyed 25 sites within Econfina River State Park located in the eastern portion of the Northern Gulf of Mexico along a salinity gradient from freshwater upstream to coastal seagrass beds downstream. DNA extracted from the top 10 cm of sediment were 16S rRNA amplicon sequenced to determine microbial community structure. Results contribute to the understanding of microbial ecology of coastal ecosystems in the Northern Gulf of Mexico.

How to cite: Parker, S. G., Tryzbiak, B., Patel, A., Pereira, G., Chambers, L., and Beazley, M.: Spatial Variation in Sediment Bacterial Communities Along a Salinity Gradient in a Northern Gulf of Mexico Coastal Ecosystem, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-6116, https://doi.org/10.5194/egusphere-egu26-6116, 2026.

Sea level rise (SLR) is a key driver in altering spatial boundaries, species distribution, and functioning of coastal wetlands in the 21st century. Wetland adaptation to SLR depends on vertical accretion and landward migration; however, the magnitude and rate of these processes remain uncertain and are constrained by factors such as sediment supply and the availability of inland accommodation space. To enhance adaptive capacity, spatially explicit assessments are critical for identifying areas suitable for wetland migration. Nevertheless, much of the existing literature emphasises global-scale analyses with coarse spatial resolution and limited use of local SLR projections, which reduces their applicability for regional and local decision-making.

We conducted a scenario-based assessment of the potential extent of landward migration for mangroves and saltmarshes in Victoria, Australia, using high-resolution (10 m) regional spatial data under two socio-economic pathways (SSP2 and SSP5) for 2070 and 2090. The results indicate that, for both ecosystems, potential area gains from landward migration exceed losses from seaward inundation. For saltmarshes, ecosystem losses are driven more by mangrove encroachment (53%) than by inundation (47%). Land tenure emerges as a key factor shaping wetland migration capacity. Future accommodation space for mangroves is largely under public ownership (56%), primarily within protected areas and nature reserves (56.2%), providing a relatively secure buffer for inland migration. In contrast, most accommodation space for saltmarshes is privately owned (56.4%) and predominantly associated with primary production land use (45.4%). Without specific management actions, saltmarshes are likely to experience losses from both expanding mangroves and ongoing land-use pressures. Overall, these findings provide valuable insights to support stakeholders in scenario-based planning and the management of coastal and urban areas to enable wetland adaptation to rising sea levels.

How to cite: Perera, N., Wartman, M., Nuyt, S., Macreadie, P., and Duarte de Paula Costa, M.: Landward Migration of Coastal Wetlands under Land-Use Constraints in Australia, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15259, https://doi.org/10.5194/egusphere-egu26-15259, 2026.

Seagrass ecosystems in Indonesia provide a diverse array of services and societal benefits that helps to mitigate the impacts of climate change, yet they face complex threats and ongoing declines. Assessing their diverse values through pluralistic lenses can provide important baseline information to guide future conservation and restoration policies. Utilising the Seagrass Ecosystem Contributions to People (SCP) framework, a systematic review was conducted in representative seagrass ecosystem regions—west (Bintan), central (Selayar), and east (Ternate)—to examine the current state of research on their diverse values. Specifically, we identified the presence, perceived worldviews, characteristics, specific values, and their overlaps of SCP categories.

Publications were retrieved from Scopus, Web of Science, and the first ten pages of Google Scholar between February and April 2025. Then, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 Guideline, a thorough literature analysis was conducted using six established inclusion criteria. Present SCPs, perceived worldviews, specific values, and their overlaps were assessed in accordance with core meanings derived from McKenzie and Colleagues, the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) report on the diverse values of nature, and Himes and Colleagues’ publication, respectively.

Overall, 54 publications were included in this review, spanning the years 1989 to 2025 and identifying 25 SCPs across three regions, with a decreasing number of studies for each SCP from west to east. There were imbalances in the SCP perception, with bioindicator and scientific research being perceived in all regions and having twice the number of publications compared to other SCPs. These two prevalent SCPs generally studied the ecological status of seagrasses, their associated biota, and experimental results on their monitoring methods (e.g. remote sensing).  

Biocentric and anthropocentric worldviews were researched more and dominated interchangeably between SCPs, focusing on seagrass conservation values and societal perceptions of its services. Meanwhile, the pluricentric worldview had singular studies limited to several Material and Nonmaterial SCPs. Excluding the east region, all three specific values (intrinsic, instrumental, and relational) were present, with instrumental as the most frequent overlapping value. These value overlaps demonstrated fuzzy boundaries between material and nonmaterial groups, but not with the regulating SCPs, which were all studied with a singular specific value.

Regional differences in seagrass ecosystem management, benefit utilizations, and research focus might reflect the variability of the perceived SCPs, worldviews, and value overlaps. Although these perceptions are still biased towards tangible benefits for human ends. However, most of the reviewed publications were short-term studies and distinct from each other, demonstrating the need for local experts’ knowledge elicitation to further weave the information. Our study further developed the SCP framework by incorporating the concept of nature’s diverse values, which is highly relevant and applicable to the seagrass socio-ecological setting and management initiatives in Indonesia.

How to cite: Widanto, D. S., Sasmito, S. D., and Waltham, N.: A systematic review of the diverse values of Seagrass Contributions to People (SCP) in Indonesia: A pilot study, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-984, https://doi.org/10.5194/egusphere-egu26-984, 2026.

Evidence suggests cetaceans utilise magnetoreception to navigate using magnetic fields. However, disturbances in the geomagnetic field from solar storms and anthropogenic activity can lead to beachings. Previous studies indicate fluctuations around 50 nT are large enough to influence strandings. Ísafjarðardjúp is home to a large humpback whale population in the summer, but marine activity, including fish farms, vessel traffic and coastal structures such as the Bolafjall radar station, makes the fjord prone to magnetic interference, potentially intefering with magnetoreception.  

How to cite: Rahman, A.: Magnetic Disturbances to Cetaceans in Isafjörðurdjup, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8273, https://doi.org/10.5194/egusphere-egu26-8273, 2026.

To support resilient community planning and informed hazard mitigation decisions, having an effective flood risk evaluation is very important especially in coastal and flood prone areas. This presentation is focused on the development of an interactive web-based decision-making platform designed to analyze future flood risk and elevation ordinance impacts across five parishes in Louisiana, USA. The website allows users to explore long-term flood risk projections and ordinance related costs over multiple future decades from 2030 to 2100. The platform integrates various geospatial datasets including multi-return-period flood depth projections, decadal population forecasts, and building inventories. Flood depth raster datasets are converted from raster to point data using python and then assigned to building data obtained from Coastal Protection and Restoration Authority (CPRA) using spatial join. Then the obtained datasets are used to calculate Average Annual Loss (AAL) for different elevation ordinances. This framework incorporates a range of flood elevation ordinances, including ASCE 24-14, ASCE 24-24, and freeboard-based standards (BFE +1’, +2’, and +3’), with ordinance costs and risk outcomes by decade. ArcGIS Pro is used for spatial analysis and 3D geospatial visualization, while interactive webpages and different elevation ordinance scenario comparisons are implemented with react vita app. To improve accessibility for non-technical users, the website integrates AI-driven features that assist users in navigating the tool, interpreting results, and comparing ordinance scenarios. The platform supports hotspot analysis, side-by-side visualization of present and future flood risks, and iterative refinement through user feedback sessions. Overall, this tool provides planners, homeowners, and policymakers with a forward-looking environment to assess flood mitigation strategies, ordinance performance, and population-driven risk changes over time by combining advanced spatial analytics with interactive and user-centered design.

How to cite: Kunku, L. P., Friedland, C. J., and Mostafiz, R. B.: Assessing Long-Term Flood Risk and Elevation Ordinance Comparisons Using a Web-Based Geospatial Decision Tool, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-4510, https://doi.org/10.5194/egusphere-egu26-4510, 2026.

Urbanization, together with increasing global population pressure and climate variability, has introduced heat-related challenges across urban areas, severely impacting humans and the Earth. The rapid population growth has placed India at the top of the global population ranking. Demographic surges concentrate stress on existing urban systems, making Indian metropolises-both inland hubs and rapidly transforming coastal centers-critical laboratories for studying UHI dynamics.

The understanding of patterns and possible causes of the UHI effect due to urbanization-induced anthropogenic activities is a vital area in urban climate research. This study presents an overall multi-decadal day/night spatiotemporal seasonal analysis and trends in LST and UHI for six Indian cities: Ahmedabad, Mumbai, Panjim, Mangalore, Kochi, and Thiruvananthapuram, spanning the last three decades.

MODIS LST and AOD data are used to explain the possible reasons for the change in LST and UHI, focusing on the seasonal thermal behavior of cities under prevailing atmospheric, meteorological, and anthropogenic conditions. The Landsat series datasets are used to develop LULC maps and delineate high-resolution UHI zones, to explain shared trajectories and city-specific patterns that expose complex vulnerabilities within urban ecosystems in India. The findings, which integrate multi-decadal 30-year satellite-derived LST, LULC, and AOD data, demonstrate that greater increases in nighttime LST are associated with a decrease in the diurnal temperature range across all cities. Mumbai consistently showed lower mean LST values compared to Ahmedabad, which exhibited substantially higher values and extreme seasonal amplitudes ranging from 17.23 °C to 50.05 °C. Goa and Mangalore depicted a 1-4 °C increase in seasonal mean LST between 1993 and 2023. Corresponding to a rise in built-up area and a decline in vegetation, Kochi too exhibited a rise in LST. Thiruvananthapuram showed a strong warming, with a mean LST increase of about 3°C. AOD patterns also demonstrated similar spatial and temporal gradients across cities, helping to reinforce land-use change, urban expansion, and inland-coastal climatic contrasts as the significant causes of LST trends.

Collectively, these findings reveal how land-use transition, and climatic variability, significantly alters the thermal environment of Indian cities; making such studies important for climate-responsive planning and better urban management to enhance resilience and thermal comfort.

How to cite: Rai, R. and Murali R, M.: Utilising geospatial data to understand urban heat island and its effect on urban thermal comfort in selected Indian cities using Remote Sensing and GIS, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-488, https://doi.org/10.5194/egusphere-egu26-488, 2026.

Mediterranean forest ecosystems are currently facing severe challenges due to the combined pressures of biotic and abiotic stressors. In particular, Holm oak (Quercus ilex L.) forests are experiencing a widespread decline driven by the effects of climate change-induced drought and the aggression of the soil pathogen Phytophthora cinnamomi. This decline threatens not only forest biodiversity but also the stability of essential ecosystem services. In response to this problem, the LIFE RECLOAK project aims to restore and improve the conservation status of these threatened habitats. The project adopts an approach involving the genetic selection of drought-tolerant and pathogen-resistant genotypes, their micropropagation, and subsequent planting in pilot sites across Italy, Spain, and Malta. Within this framework, Work Package 7 (WP7) is dedicated to the "Evaluation of ecosystem functioning and climate mitigation effects," validating the success of the reforestation efforts. Therefore, the primary objective of WP7 is to quantify the restoration of ecosystem processes and the enhancement of climate change mitigation potential provided by the selected resistant genotypes compared to traditional forest stock.

The activities of WP7 integrate field monitoring and modelling tasks. Firstly, the project will assess vegetation growth and biodiversity. In the pilot sites, key morphological parameters of Q. ilex (such as Basal Diameter (BD), Plant Height (PH), and Leaf Area Index (LAI)) will be measured annually to track biomass accumulation. Concurrently, biodiversity indexes (BI) will be calculated to monitor the recovery of understory vegetation. To evaluate the restoration of below-ground processes, soil quality will be assessed through measurements of soil respiration, Soil Organic Carbon (SOC), erosion rates, and Water Holding Capacity (WHC). Recognizing the slow growth rate of holm oaks, these monitoring activities are planned to continue for ten years after the project's conclusion, ensuring a long-term perspective on ecosystem recovery. Data collected from vegetation and soil monitoring will be used for the assessment of carbon sequestration, calculating the CO₂ absorbed by both the woody biomass and the soil compartment. WP7 will also develop a monitoring tool using the Biome-BGC Musso ecohydrological model. By integrating site-specific pedoclimatic data with the physiological traits of the resistant genotypes, this model will be calibrated to simulate carbon and water pathways (e.g., Water Use Efficiency) over the plantation's lifespan. This approach quantifies the added value of the resistant genotypes, demonstrating their superior resilience under changing environmental and management conditions.

Finally, under the coordination of the Democritus University of Thrace, WP7 will integrate these findings to analyze broader Ecosystem Services (ES), including provisioning, regulating, and supporting functions. Ultimately, by validating biological indicators and establishing a robust carbon monitoring protocol, WP7 will demonstrate the effectiveness of using improved genotypes, offering a replicable model for restoring Mediterranean areas affected by forest dieback.

How to cite: gori, A., beltrami, S., alderotti, F., ferrini, F., dibari, C., ferrise, R., paffetti, D., and brunetti, C.: Restoring Mediterranean holm oak forests: ecosystem functioning and climate mitigation in the LIFE RECLOAK project, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-16743, https://doi.org/10.5194/egusphere-egu26-16743, 2026.

Climate change is increasing the frequency and intensity of drought and heat events in Mediterranean regions, urging the need for resilient fruit crops that link stress tolerance to relevant fruit quality traits. My PhD project focuses on the strawberry tree (Arbutus unedo L.), an underutilised Mediterranean evergreen fruit species of considerable ecological relevance in Southern Europe, with a recognised capacity to cope with diverse abiotic and biotic constraints. The project objective is to characterise six Italian A. unedo populations in terms of physiological performance under water-limited conditions and fruit quality characteristics. The primary step is to select provenances with contrasting pedoclimatic characteristics and to use calculated climatic indices (e.g., Emberger’s Q2) across an aridity–temperature gradient. These provenances are then screened for constitutive traits under well-watered conditions combining measurements of xylem vulnerability to embolism formation (P50), water-use strategy (e.g., minimum epidermal conductance, g_min; specific leaf area, SLA), and cellular drought tolerance derived from pressure–volume analysis (turgor loss point, TLP; osmotic potential at full turgor, π₀; and modulus of elasticity, ε).  After that, inducible trait modifications are tested under water stress and recovery conditions, monitoring gas exchange, plant water relations, chlorophyll fluorescence parameters, hydraulic resistance, and growth. In parallel,  a core component of the work investigates fruit physiological performance across different ripening stages (identified by skin colour) and during post-harvest storage. Fruits, harvested at the yellow–orange stage, are analysed for respiratory activity using a custom fruit chamber coupled to a LI-COR 6800 system. Post-harvest dynamics are monitored under two storage treatments (ambient temperature vs. 4 °C) and related to quality attributes, including colour development, soluble solids (°Brix), firmness, weight loss, pectin content, sugar profile, and polyphenol-related traits. Within this post-harvest study, the project also considers the use of edible coatings as a practical tool to modulate storage techniques and help preserve the quality attributes of this perishable fruit. Therefore, integrating provenance screening with fruit respiration and post-harvest physiology provides a practical basis for selecting A. unedo genotypes with improved drought resilience and high fruit yield and quality, thereby fostering A. unedo cultivation in Mediterranean areas under a changing climate.

How to cite: Pascucci, G., Alderotti, F., Lo Piccolo, E., Beltrami, S., Detti, C., Baptista, A., Palchetti, V., Bini, L., Ferrini, F., Antunes, M. D., Giordani, E., Brunetti, C., and Gori, A.: Drought resilience and fruit performance in strawberry tree (Arbutus unedo L.) populations: ecophysiological screening and postharvest behaviour , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-21475, https://doi.org/10.5194/egusphere-egu26-21475, 2026.

Methane emissions from natural wetlands are the largest and most uncertain component in the global methane budget. Conventionally they are estimated using two main methods. Top-Down methods work by inverting atmospheric concentrations of methane into fluxes, using a chemistry transport model. This is often done by optimizing the scaling factors of the inventory flux maps, but this approach decouples the fluxes from their physics and has limited predictive capabilities. Conversely, Bottom-up methods use biogeochemical models to directly estimate the fluxes, but they are severely affected by the scarcity of in-situ flux observations to calibrate them. To bridge this gap, we present the development and validation of a new fully coupled Methane Data Assimilation System (CH4DAS). This system integrates these two techniques, and provides constraints to the bottom-up model (ie., optimizing its main parameters) from both satellite concentrations and site-level fluxes. Such integration ensures that flux estimates remain consistent with physical drivers, simultaneously addressing data scarcity and enabling predictive capability.

CH4DAS is developed within the Community Inversion Framework (Berchet et al., 2021) and couples SatWetCH4 (Bernard et al., 2025), a simple bottom-up wetland methane model with the LMDz-SACS chemistry-transport model. This system can simultaneously assimilate both satellite concentrations (GOSAT) and site-level in-situ fluxes (FLUXNET-CH4) within a variational assimilation scheme to constrain the model parameters. To address the scale challenges while simultaneously assimilating observations of different streams, we run two instances of SatWetCH4. The first, driven by global forcing is coupled with LMDz-SACS and constrained by Satellite observations. While the second instance driven by site-level forcing is constrained by in-situ fluxes. This way, the shared internal temperature sensitivity parameter Q₁₀⁰ is jointly constrained by two data streams, while site-level and regional base rate parameter K account for data-specific variability.

We mathematically validate the system using an Identical Twin Observing System Simulation Experiment (OSSE), demonstrating its capacity to constrain the control variables. Further, we apply the system to real-world data to demonstrate that the system can successfully reduce the mismatches in the prior to match the spatiotemporal gradients observed by GOSAT, enabling insights on regional CH4 budgets.

How to cite: Vetriselvan, R., Rayner, P., Berchet, A., Peylin, P., Salmon, E., Saunois, M., Bernard, J., and Singh, A.: Beyond Static Fluxes: Constraining parameters of a wetland methane model in a new fully coupled CH4DAS using Satellite Concentrations and In-Situ Fluxes, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12474, https://doi.org/10.5194/egusphere-egu26-12474, 2026.

Biological soil crusts (biocrusts) are increasingly recognized as important components of ecosystems. Biocrusts are instrumental in maintaining functions such as soil stability and reduced abundance of invasive annual grasses. Impacts of fire are likely to be less severe where invasive plants are reduced and biocrusts are abundant. These organisms can thrive under drought conditions and help intact ecosystems be more resilient to drought. However, expertise on these organisms remains limited.  Practitioners are often interested in the topic but might feel they would benefit from additional resources on how to identify these organisms. We have developed a single-page, front and back guide that enables anyone, regardless of previous experience, to recognize biocrusts in the field and categorize them into ecologically meaningful groups, with known functional roles. The guide has been tested both in the field and by examining biocrust samples in hand. Data associated with testing the guide was used to improve it. The resulting guide describes higher-level groups of algae, mosses, and lichens. Light algal crusts are described as their own group. Dark algal crusts are presented with gelatinous lichens due to similar ecologies and increased accuracy of identification when these groups are combined. The determination of algal crusts was accepted as correct, regardless of the light or dark designation, due to the quality of our samples. Mosses are split into short and tall. In addition to the gelatinous lichens / dark algal crust group, lichens were classified into five additional categories: crustose, cup, foliose, fruticose, and scale. This tool has been created from the ground up, driven largely by the accuracy with which non-experts can correctly classify presented groups. In addition to reporting on the accuracy of each group, we explain how sample type (resin, dried and in petri dishes, or enlarged photographs) played a role in the accuracy of identification. We describe the ecology and functional roles of the presented groups, giving further justification for their classification. We anticipate that adoption of the guide is likely to have far-reaching implications, such as an increase in the number of studies on biocrusts at the level of functional roles. 

How to cite: Condon, L., Barker, C., and Coates, P.: Alleviating Biocrust Blindness: An Easy Guide to Morphogroups of Biocrusts , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-22143, https://doi.org/10.5194/egusphere-egu26-22143, 2026.

The Lomagundi-Jatuli event (2.3-2.0 Ga) is one of the grandest carbon isotopic (δ¹³C_carbonate) excursion events in the Earth’s history, marked by anomalous δ¹³C_carbonate reaching up to + 30 ‰. Several hypotheses have been proposed to explain this excursion; however, they remain inadequate due to associated drawbacks. The conventional explanation is organic carbon burial due to enhanced productivity. But, the lack of organic rich stratas synchronous with the excursion demands the reconsideration of alternative biogeochemical processes to explain this isotopic anomaly. Moreover, the excursion is observed only in the evaporitic and nearshore carbonates, with no evidence from open ocean; demanding facies based biogeochemical explanation. Here, we explore the possibility of CO₂ outgassing and calcite precipitation as potential drivers responsible for this excursion as these two processes remain the least explored among the proposed hypotheses. Through sedimentological evidences from previous studies and Rayleigh fractionation calculations, we argue that dominant loss of DIC through CO₂ outgassing in the evaporitic facies and calcite precipitation in the nearshore facies along with a well-mixed DIC reservoir in the open ocean led to observed Lomagundi Excursion.

How to cite: Janaarthanan, P. A. and Kumar, S.: Can CO2 outgassing explain Lomagundi Excursion?, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7342, https://doi.org/10.5194/egusphere-egu26-7342, 2026.

Terrestrial ecosystems currently absorb a substantial proportion of anthropogenic carbon dioxide (CO₂) emissions, yet the persistence of this land carbon sink under accelerating climate change remains largely uncertain. While process-based vegetation models project continued enhancement of carbon uptake through CO₂ fertilization, there are growing observational evidence that suggests that climate extremes, particularly 3^oC global warming level, may substantially constrain or reverse these gains through droughts and heatwaves. Recent global carbon budget assessments also show a rapid weakening of the land carbon sink, with dynamic global vegetation model ensembles and atmospheric inversions indicating a large decline in net land uptake between 2022 and 2023. Here we present an observation-constrained, species-specific quantification of global terrestrial carbon fluxes across major terrestrial biomes. We integrate a combination of satellite-derived vegetation indices, a geo-referenced global database of climate-induced tree mortality, and dynamic global vegetation models from the TRENDY intercomparison models to map spatial and temporal variability in carbon uptake, storage, and loss under historical and future climate conditions. Model simulations are forced with regionally downscaled climate projections and explicitly constrained using observed mortality signals to quantify the effects of CO₂ fertilization. Our results reveal a widespread divergence between modelled and observation-constrained carbon fluxes, with some biomes exhibiting a reduced carbon sink. Species adapted to moderately moist climate conditions show strong sink-to-source transitions, while drought-tolerant species exhibit greater resilience but limited long-term sequestration capacity. These findings demonstrate that climate extremes impose substantial limits on terrestrial carbon sequestration. By linking species-level ecological responses with carbon flux dynamics, our study provides a more realistic assessment of the future role of terrestrial ecosystems in regulating the global carbon cycle under ongoing climate change, as well as show species and regions for optimal sequestration.

Key words: Carbon Flux, Carbon Dioxide Removal, Biomes, Dynamic Vegetation Models, Drought, Heatwave

How to cite: Lawal, S. and Stewarts, W.: Mapping Global Carbon Flux in Species across Terrestrial Biomes Under Climate Extremes, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-14745, https://doi.org/10.5194/egusphere-egu26-14745, 2026.

Fire is a dominant disturbance in tropical and subtropical dry forests and a major contributor to variability in carbon emissions, atmospheric composition, and land–atmosphere interactions. Despite their global extent and rapid transformation, the processes controlling fire size and extreme fire events in dry forest systems remain less understood than in savannas or humid tropical forests.

We investigated the controls on fire size using the South American Gran Chaco as a representative large-scale tropical dry forest system spanning strong climatic, ecological, and land-use gradients. We analyzed two decades (2001–2022) of satellite-derived fire patches from the FRY v2.0 burned-area database, combined with ERA5-Land meteorology and Fire Weather Index diagnostics, land-cover composition, landscape fragmentation metrics, topography, and anthropogenic pressure proxies. Our analysis focuses explicitly on fire size rather than fire occurrence, using statistical approaches and machine learning tools such as Random Forest models with SHAP-based interpretation to disentangle the relative and interacting roles of atmospheric forcing, landscape structure, and human-driven land transformation.

Our results show that fire size distributions are highly skewed across the region, with a small fraction of large and extreme events accounting for a disproportionately large share of total burned area. Wind and atmospheric dryness exert a strong influence on the final shape and size. At the same time, precipitation plays opposing roles by constraining fire spread through fuel moisture and enhancing fuel accumulation in fuel-limited environments. Landscape structure mediates the translation of meteorological extremes into large burned areas, with land-cover composition, fuel continuity, and fragmentation consistently ranking among the most influential predictors of burned area. Topography systematically emerges as the dominant predictor across subregions and seasons, acting not as a direct driver of fire spread but as an integrative proxy capturing hydrological gradients, vegetation structure, and human accessibility. Direct anthropogenic proxies show weaker importance at the event scale but exert strong indirect control through long-term land-use change and fuel reorganization, which in turn modulate fuel continuity and landscape configuration.

These results highlight tropical dry forests as a distinct fire domain where fire size emerges from coupled climate–biosphere–human interactions. By combining Earth observation fire products with explainable machine-learning approaches, this study advances understanding of fire–Earth system interactions and supports improved fire-risk assessment in rapidly transforming dry forest regions.

How to cite: San Martín, R., Ottlé, C., Sorenssön, A., Mouillot, F., and Vaittinada Ayar, P.: Atmospheric and landscape controls on fire size in tropical dry forests: insights from the South American Gran Chaco, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7609, https://doi.org/10.5194/egusphere-egu26-7609, 2026.

Land-use change in tropical regions has profoundly altered forest structure, disturbance regimes, and recovery pathways over recent decades, with important implications for fire activity and land–atmosphere interactions. Medium-resolution global land cover products are widely used to analyze these dynamics in climate and Earth system studies, yet their capacity to distinguish native forests from planted tree crops across disturbance and recovery phases remains limited. This raises critical questions about how forest loss, recovery, and resilience are inferred from satellite-based observations in human-modified tropical landscapes.

Here, we examine how forest-to-tree-crop transitions are represented in the ESA CCI Land Cover medium-resolution land cover (MRLC) product at 300 m spatial resolution over the period 1992–2022, and how these transitions relate to fire occurrence across Southeast Asia. We combine MRLC land cover maps and land cover transition layers with a high-resolution global dataset of planted tree crops providing spatial extent and year of establishment (Descals et al., 2024), together with fire information from FireCCI v5.1 at 250 m resolution (2001–2022) and fire polygon data from FRY v2.0. This integrated framework allows us to place land-cover changes associated with plantation establishment and maturation in the context of disturbance–recovery processes.

Our analysis focuses on land cover trajectories from native evergreen broadleaf forest to mosaic classes during plantation establishment, followed by reclassification to broadleaf tree cover as plantations mature. We examine the timing and duration of these transitions and their association with fire occurrence during land-use change. Preliminary results show systematic patterns in which oil palm expansion is linked to transient forest loss and elevated fire activity during early plantation stages, followed by reduced fire occurrence as plantations develop before being mapped again as tree cover.

These results demonstrate that confusion between native forests and planted tree crops in medium-resolution land cover products can lead to misleading interpretations of post-disturbance recovery and forest resilience. In particular, apparent forest recovery detected by satellite products may in some cases reflect a land-use replacement rather than true ecosystem recovery with important implications for the interpretation of disturbance–recovery dynamics, as well as for climate modeling and projections in human-modified tropical landscapes. This highlights the need for complementary high-resolution land cover information, such as that developed within the ESA CCI High Resolution Land Cover (HRLC) project, to better disentangle recovery from land-use change.

How to cite: San Martín, R., Ottlé, C., Peylin, P., Lamarche, C., and Mouillot, F.: From native forests to planted tree crops: disentangling tree cover transitions driven by deforestation, fire, and plantation development using satellite observations, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12372, https://doi.org/10.5194/egusphere-egu26-12372, 2026.

Climate change accelerates the global hydrological cycle, which has escalating impacts on human health and the socioeconomic development. However, many existing Earth system models neglect the more complex processes of topography-driven vegetation-surface-groundwater interactions, thereby failing to accurately capture climate-hydrological responses. To address this gap, we integrate the three-dimensional surface-subsurface hydrological model ParFlow with the dynamic global vegetation model LPJ-GUESS to investigate how lateral groundwater flow and vegetation dynamics jointly regulate hydrological fluxes. The fully coupled ParFlow-LPJ-GUESS (PF-LPJG) model (with and without lateral flow) and stand-alone LPJ-GUESS model were used to run hydrological simulations over a 38-year period at a resolution of 10 km across the Danube River Basin. The results demonstrate that the PF-LPJG model substantially improves streamflow and surface soil moisture simulations without requiring parameter calibration compared to stand-alone LPJ-GUESS, mitigates the underestimation of summer low flows during dry years, increases the accuracy of peak flow timing in wet years, and achieves a Kling-Gupta Efficiency (KGE) > 0.5 and Spearman’s ρ > 0.80 at over 80 % of gauging stations. Seasonal soil moisture anomalies are better captured (R = 0.51) compared to satellite-based products. Additionally, the modelled WTD agrees well with in-situ monitoring-well data, as indicated by a low RSR value (~1.31). Notably, the coupled model improves the representation of bare-soil evaporation and reduces transpiration-to-evaporation (T/E) ratio fluctuations, aligning more closely with the GLEAM v4.2 product. Sensitivity analysis reveals that shallow-rooted vegetation exhibits strong decreases in LAI and AET when lateral flow is removed, while slightly increasing LAI and AET in deep-rooted regions. The coupled model PF-LPJG entails a mechanistic framework for capturing bidirectional interactions among surface-subsurface water, vegetation dynamics and ecosystem biogeochemical processes, which can be applied to other catchments or climatic conditions to deeply analyze climate-induced modification on vegetation-water-carbon interactions. Future work will focus on how the lateral flow affects vegetation greening under different climatic conditions.

How to cite: Jia, Z., Fu, Y. H., Chen, S., and Tang, J.: Advancing Ecohydrological Modelling with Coupled ParFlow-LPJ-GUESS: Role of Lateral Flow in Vegetation and Hydrology Simulations, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-16516, https://doi.org/10.5194/egusphere-egu26-16516, 2026.