This session addresses peatland hydrology and its interaction with ecosystem processes across all latitudes. We invite contributions that advance our understanding of groundwater and surface water processes in peatlands and their role in ecosystem functioning, across scales from pore structure to catchments to continental scale. We particularly welcome studies that look beyond the topmost active layer and consider the entire peat profile as well as aquifer–peatland interactions, and encourage papers from understudied regions where field studies are scarce and inclusion into Earth system models is largely pending. We invite submissions on: (1) hydrological processes operating in all types of peatlands (pristine, disturbed, degraded, drained, managed, rehabilitated or re-wetted) in boreal, temperate, and tropical latitudes; and (2) the first-order control of peatland hydrology on all kinds of peatland functions.
We aim to advance the transfer of knowledge and methods, and welcome laboratory, field, remote sensing, and modeling studies on hydrological, hydrochemical, biogeochemical, ecohydrological or geophysical topics, as well as ecosystem service assessments within peat-dominated landscapes.
Peatlands store more carbon (C) than any other terrestrial ecosystem and as a C sink they are vital to mitigating climate change. The keystone of many peatland ecosystems is Sphagnum, a bryophyte genus of ca. 350 species found on every continent except Antarctica. With climate change, many peatlands face increasing frequency and severity of drought. How Sphagnum responds to, and recovers from, drought will be key to sustaining peatlands over the coming decades.
Through a combination of microcosm and field experiments we investigate how different Sphagnum species will respond to short- and long-term drought periods. We detail the effects of drought on Sphagnum C cycling and biochemistry, including photosynthesis, growth, respiration and methane (CH4) fluxes. We show that there are species-specific limits to the ability of Sphagnum to withstand drought and that these align with the adaptations associated with the hummock-hollow microtopography of peatlands. Through this work we identify drought resilience, including a hysteresis between Sphagnum moisture content and C uptake which is delineated by pre-drought and rewetting. We discuss tipping points and determine C sink-source thresholds in Sphagnum which will have vital implications for future peatland C cycling.
How to cite: Keane, J. B., Clay, G. D., Overtoom, N., Ritson, J. P., Evans, M. G., Harris, A., and Johnston, A.: The effects of drought on Sphagnum moss species and the implications for peatland carbon cycling in a changing climate, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-20978, https://doi.org/10.5194/egusphere-egu26-20978, 2026.
Montane peatlands are highly sensitive to climate change and disturbance, and their hydrological functioning strongly controls the transport of dissolved substances. Electrical conductivity (EC) serves as an integrative tracer of runoff generation processes and source contributions. This study analyzes long-term changes in EC-discharge (EC-Q) dynamics in response to climate warming and a multi-year drought in the Rokytka peatland, Central Šumava Mountains (Czechia) in response to climate warming and a multi-year drought. The drought is treated as a stress-test period that reveals the sensitivity and dominant response pathways of the system, indicating the likely direction of change as heat and drought intensify under climate warming.
We use a unique 20-year dataset of 10-minute measurements of discharge, EC, and meteorological variables. Runoff events were classified by antecedent wetness and event structure, and water circulation patterns were analyzed using event-scale EC-Q hysteresis loops characterized by loop direction and morphology. Events were further compared across seasons and major climatic and management phases.
Results show a pronounced shift after the onset of the warm and dry period in 2015–2018. Discharge regimes exhibit higher variability, more frequent extremes, and lower baseflow. Hydrographs became steeper, with shorter response times, faster rising and falling limbs, smaller event runoff volumes, and more asymmetric shapes. EC dynamics changed consistently: maximum EC values decreased, event-scale EC contrasts weakened, and EC returned more rapidly to baseline after events.
EC-Q hysteresis loops also changed markedly. Hysteresis indices decreased and separation between rising and falling limbs weakened, indicating reduced event-scale contrasts in solute sources and more uniform mixing. Loop direction shifted toward more frequent clockwise patterns after 2015, consistent with earlier flushing followed by dilution. Together, these changes point to faster runoff generation and altered solute mobilization under warmer and drier conditions.
The study demonstrates that long-term high-frequency EC monitoring provides a sensitive indicator of climate- and management-driven changes in peatland hydrology. EC-Q hysteresis analysis offers a powerful tool for diagnosing shifts in runoff generation, storage, and solute transport, and for evaluating the effectiveness of peatland restoration under a changing climate.
How to cite: Langhammer, J. and Bernsteinová, J.: Electrical conductivity as a tracer of changing peatland catchment response to climate warming, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8112, https://doi.org/10.5194/egusphere-egu26-8112, 2026.
The Hydrologic Understory is an integrated research and extension project that explores groundwater flowpaths, surface water mixing, underground thermal regimes and soil moisture monitoring to map out the interconnected web of hydrology and ecology beneath the surface ultimately helping guide management of wetlands, including attracting desirable native species, creating and maintaining habitat for rare and endangered species including Atlantic White Cedar, cold water fishes and optimal water quality.
In this cranberry-bog-turned-restored-freshwater-wetland, the largest in Massachusetts, we are exploring first principles measurements of hydrologic parameters to help guide restoration practices and management of this former peatland. One of the most basic, defining metrics of a wetland is, as the name implies, its wetness. We explore time series of temperature and water elevation data at a restoration site from retired farm, through restoration, and wetland development. While single measurements can indicate the groundwater table elevation below the ground surface at one time (a useful delineation metric), long time series can indicate how the site responds to storm flows, droughts, and other conditions; and how those responses are changed by restoration practice. Coupled with streamflow data, net water balance can be calculated as well as water residence time. Temperature data serves as an indicator of thermal buffering capacity, the potential for development of thermal refugia for wildlife, and a tracer to locate influxes of groundwater. We use thermal imagery from UAS before and after restoration to map the surface expression of groundwater, and document the arc of change as the site rewilds. Distributed temperature sensing (DTS) buried at 10, 20 and 30 cm depths across the site allow for estimates of groundwater upwelling and soil moisture through time without creating additional subsurface disturbance.
Understanding long-term ecosystem dynamics in southeastern Massachusetts is achieved through a pollen and charcoal analysis of deep sediment cores spanning 9,140 years. This fire history record provides critical context for current restoration efforts of Atlantic White Cedar swamps, a rare and threatened ecosystem type in New England. Efforts are underway to co-steward these swamps together with local indigenous groups for whom they are critically important.
While the cranberry farming industry is in decline owing to competition from less expensive land and more productive varietals in other locations, everything under historic cranberry farms is ripe for resilient wetland restoration projects. These low-lying water-rich areas are underlain by glacial geology (peats and clays) that are ideal for holding water, possess large accumulations of organic and hydric soils, and are currently sought-after by a statewide restoration program that aims to create a self-sustaining, resilient freshwater wetlands - promising hydrologic metrics are the first indicator of that success.
How to cite: Hatch, C., Watts, C. L., and MacDonald, D.: Views of a restored peatland from the past, underground, and future cedar swamp, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-22034, https://doi.org/10.5194/egusphere-egu26-22034, 2026.
Peatland management, conservation, and restoration rely on a thorough understanding of peatland hydrogeology and carbon dynamics. To date, most of the information about peatland subsurface properties is derived from laboratory analyses of borehole samples, which allow direct measurement of hydrogeological and geochemical parameters but provide only point-wise information. Here, we present the use of the low-frequency electrical impedance tomography (EIT) to investigate hydrogeological properties and carbon dynamics in alpine peatlands in an imaging framework. In particular, we aim to map biogeochemical hotspots and to delineate flow paths controlling surface-groundwater interactions and nutrient cycles. The EIT method is an extension of the widely-used electrical resistivity tomography (ERT), which deploy electrodes (placed on the ground) to inject current to resolve the conductive (conductivity) and capacitive (polarization) properties of the subsurface along 2D planes or 3D volumes. While the electrical conductivity (due to migration of charges in the pore space) has been commonly used to investigate variations in saturation, porosity and fluid electrical conductivity (EC); the polarization (i.e., capacitive effect, resulting from accumulation and polarization of charges in the fluid-grain interface), provides a unique opportunity to gain information about changes in pore-space geometry, cations exchange capacity and soil organic carbon (SOC). To resolve the frequency-dependence of the electrical properties, imaging measurements were collected in the range between 0.1 and 75 Hz, while vertical soundings were conducted between 0.1 and 1000 Hz. This information is needed to discriminate between SOC and clay content and quantify changes in hydraulic properties. The geophysical investigations are supported by the analysis of material extracted from boreholes.
The EIT surveys were conducted across six alpine peatlands in Austria to characterize the variability in electrical properties at both local (site-specific) and regional (inter-site) scales. The investigated peatlands mainly originated through terrestrialisation of lakes that had formed in glacially eroded depressions at the end of the Last Glacial Maximum. Accordingly, substratum is dominated by lacustrine fines in direct proximity to glacial sediments and various types of alpine bedrock.
Our results reveal that the electrical conductivity and polarization are consistent for data collected across the different peatlands, supporting the relevance of the EIT method for peatlands investigations. We demonstrate that incorporating polarization as an additional parameter alongside electrical conductivity improves the resolution of peat thickness compared to interpretations based solely on electrical conductivity. Moreover, the polarization response reveals clear spatial variations related to geochemical variations in the organic soil. While the electrical properties are consistent, important changes in the polarization response can be observed in degraded peatlands, demonstrating the potential of the EIT method for the design of remediation and conservation strategies. Ongoing tracer experiments aim to validate petrophysical models connecting electrical and hydraulic properties in an imaging framework.
How to cite: Flores Orozco, A., Akalovic, K., Steiner, L., Francis, S., Moser, C., Hopfinger, M., and Salcher, B.: Imaging peatland hydrogeological structure using electrical impedance tomography, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-14313, https://doi.org/10.5194/egusphere-egu26-14313, 2026.
In past two decades, Cosmic-Ray Neutron Sensing (CRNS) has evolved to a useful and promising approach to monitor soil moisture as well as snow water equivalents and biomass non-invasively at the hectometre-scale. Its large integration radius and average sensitive measurement depth of 20 to 30 cm allows for overcoming small-scale heterogeneities and for estimating soil moisture at spatio-temporal scales to e.g., inform environmental models or validate soil moisture products from remote sensing data.
CRNS relies on the inverse relationship between environmental hydrogen e.g., stored in soil moisture and the intensity of naturally occurring low-energy cosmic-ray neutrons. The relationship between soil moisture and neutron intensity is strongly non-linear which leads to larger uncertainties when the soil moisture is high. At the same time, neutron-to-soil moisture conversion functions have been developed for homogeneous soil moisture distributions which leads to larger uncertainties in soil moisture estimates for strongly heterogeneous conditions. Therefore, CRNS is expected to provide most accurate soil moisture estimates at monitoring sites with generally drier soils and homogeneous soil moisture distributions while knowledge gaps remain with respect to wet and heterogenous observation sites e.g., due to partial water cover.
Against this background, we investigate the signal dynamics of observed low-energy cosmic-ray neutron intensities at a wetland site in north-eastern Germany in order to gain understanding of the local background neutron flux and the potential to estimate soil moisture in water-free areas of wetland sites. Therefore, we monitor neutron intensities at two locations in the wetland with different partial water cover in the sensitive measurement radius of the individual neutron detectors, apply Monte-Carlo based neutron transport simulations and use field measurements of soil moisture to test and adjust existing neutron-to-soil moisture conversion functions to the specific conditions of the observation site.
Our analyses underline the potential of non-invasive CRNS for monitoring soil moisture dynamics in water-free areas of wetland sites which are generally considered unfavourable for the CRNS technique but also shed light on limitations at these observation sites.
How to cite: Rasche, D., Sachs, T., Kalhori, A., Morgner, M., Güntner, A., and Blume, T.: Exploring the potential of using low-energy cosmic-ray neutrons to monitor soil moisture dynamics in wetlands, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-18195, https://doi.org/10.5194/egusphere-egu26-18195, 2026.
We established a sensor network to monitor basic environmental state variables in rewetted temperate fens at an unprecedented scale as part of the TRR 410 WETSCAPES2.0 project (funded by DFG, Project-ID 531801029). Monitoring locations were selected from a pool of all peatland rewetting projects in the federal state of Mecklenburg-Vorpommern in northeastern Germany using a standardized, remote-sensing-based procedure to obtain the most representative homogeneous area in each site. At each location, we installed sensors that measure groundwater table, soil moisture, and soil/air temperature and transmit their data live via LoRaWAN.
Over the last months, more than 80 sites have been set up in coastal and freshwater fens. Despite all sites being considered “rewetted”, they cover a wide hydrological gradient: In the first few months after setup, the average water levels in fall and winter ranged from more than 50 cm below ground surface up to almost 70 cm above ground. Also, already the first months of data indicate large differences in water level amplitude per site, ranging from less than 3 cm to more than 60 cm. No relationship between mean water level and amplitude of water level fluctuations could be observed. Several sites consistently showed soil water content in the upper layer less than 75%.
As the data set continues to grow, our data will help to enhance functional understanding of spatio-temporal implications of peatland rewetting, as well as serve in practical planning of future rewetting projects.
How to cite: Günther, A., Aleksandrov, M., Jansen, F., Yadav, D., Yordanova, K., and Kreyling, J.: Unprecedented sensor network in rewetted fens in northeastern Germany reveals high variability of hydrological conditions, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19920, https://doi.org/10.5194/egusphere-egu26-19920, 2026.
Rewetting efforts to restore anthropogenically degraded peatlands across Germany aim to curb the rapid release of carbon gases onset from peat desaturation. To monitor peat saturation across remediation efforts aimed to stabilize carbon-cycling, it is paramount to understand the hydrology controlling flow through these systems. Underlying mineral sediment stratigraphy controls peatland water levels, with more permeable structures altering flowpaths and sourcing minerogenous groundwater. In this study we examined the Zarnekow wetland, a degraded fen in northeast Germany, using a suite of electrical geophysical methods to map the stratigraphic interfaces between the peat and underlying mineral sediments. Rought terrain ground-penetrating radar (GPR) and towed transient electromagnetic induction surveys were deployed to characterize the mineral sediment interface across the fen. Variability in the mineral sediment interface was then compared to hydrological temperature signals indicative of groundwater upwelling, allowing for inferences about the stratigraphic controls on groundwater flow. An extended transect within the survey area was selected for targeted GPR surveys using both common offset and common midpoint geometries. These additional data allowed for estimates of the subsurface gas content. Time-domain induced polarization was deployed over the same transect to examine contrasts between the real and imaginary components of the complex conductivity. Initial results from the focused electrical surveys provide robust spatial insight into the gas distribution within the Zarnekow wetland. This study bolsters the use of electrical geophysics for seasonal monitoring of gas migration in the subsurface, informing ongoing peatland remediation efforts.
How to cite: Moore, H., Blume, T., Wille, C., Sachs, T., Hess, R., Maceiro, J., and Uhlemann, S.: Mapping Subsurface Stratigraphy Controlling Groundwater-Surface Water Interactions and Estimating Associated Subsurface Gas Content in a Degraded Fen, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7455, https://doi.org/10.5194/egusphere-egu26-7455, 2026.
Peatland restoration, through drainage suppression, is widely implemented to recover ecological function, yet the driving hydrological mechanisms controlling groundwater responses across spatial and temporal scales remain poorly quantified. Here, we use calibrated, fully integrated 3D physics-based modeling to explicitly resolve how rewetting interventions, including ditch infilling and damming, restructure catchment-scale groundwater dynamics across a boreal fen. Simulated restoration actions elevated water tables by ~23 cm, with comparable gains in nominally undisturbed areas, demonstrating far-field impacts of drainage legacy and the re-establishment of lateral hydrological connectivity. Variogram analysis revealed that hundreds of meters of previously fragmented, drainage-controlled peatlands were transformed into hydraulically coherent systems, enhancing spatial correlation and damping extreme drawdowns. Additionally, findings revealed that lateral propagation of groundwater recovery depended on structure type and hydraulic properties, with low-permeability peat infillings produced strong local responses with steep exponential decay (~70% within ~40 m), whereas dams generated broader plateauing effects (~100 m radius). Geomorphic context further modulated outcomes, where groundwater recovery also followed exponential growth away from peat–mineral margins, with intermediate-thickness peatlands defining a tipping-point regime that maximizes recovery magnitude and variability. Seasonal dynamics amplified restoration efficiency, with wet periods nearly doubling groundwater rise relative to dry winters, yet elevated efficiency persisted during dry intervals between spring melts and autumn rains. Collectively, these findings reveal how restoration effects propagate laterally, interact with seasonal hydroclimatic forcing, and are shaped by geomorphic context, providing a transferable, mechanistic framework for prioritizing and designing restoration plans that maximize peatland hydrological recovery.
How to cite: Nimr, O., Marttila, H., Batelaan, O., Partington, D., and Ala-Aho, P.: Spatiotemporal Groundwater Responses to Peatland Restoration: A Fully Integrated Surface–Subsurface Modelling Study on a Boreal Fen, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-4194, https://doi.org/10.5194/egusphere-egu26-4194, 2026.
Peatland rewetting is an important measure for climate-change mitigation in northern Europe, but its effectiveness and plausibility require a detailed understanding of hydrological processes in degraded systems. To address this need, this study employs a fully integrated HydroGeoSphere (HGS) model of a drained fen peatland in Brandenburg, Germany, using nine years (2015–2023) of field measurements including groundwater (GW) dynamics, ditch water levels, eddy-covariance evapotranspiration (ET), and in-situ vegetation (LAI) observations. The model represents three-dimensional surface–subsurface flow, spatially distributed vegetation and management units, and a vertically heterogeneous peat profile. Evapotranspiration is parameterized using site-specific eddy-covariance data and in-situ measurements of seasonal leaf area index and management practices. Model performance was evaluated against GW levels and ET using a multi-metric approach for calibration (2016–2020) and validation (2021–2023) periods. Simulated GW dynamics and ET are in agreement with observations (GW: NSE = 0.83–0.86, KGE = 0.80–0.85; ET: RMSE ≈ 1.0 mm d⁻¹). Results show pronounced seasonal reversals in hydraulic gradients with evapotranspiration-driven groundwater drawdown leads to lateral inflow from ditches and the surrounding aquifer during summer, and recharge-driven outflow and surface inundation in winter conditions. Seasonal and interannual water-storage analysis shows that wet years (e.g., 2017, 2023) generate positive storage, whereas consecutive drought years (2018–2020) produce cumulative deficits, highlighting the vulnerability of degraded peat to climatic water imbalance. The presented modeling framework provides a robust basis for assessing peatland vulnerability to climate extremes and for evaluating rewetting and water-management strategies aimed at enhancing water retention and reducing CO₂ emissions from drained fen peatlands.
How to cite: Mahmoodi, N., Dietrich, O., Pickert, J., and Merz, C.: Quantifying water fluxes and storage in a degraded peatland using a fully integrated hydrological model, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-9171, https://doi.org/10.5194/egusphere-egu26-9171, 2026.
Hydrology plays a fundamental role in peatland functioning and controls the silicon (Si) cycle in these ecosystems. Most peatlands are groundwater-dependent systems, where interactions between aquifers, peat layers, and surface waters regulate solute transport and nutrient cycling, including dissolved silicon (DSi). DSi is a key nutrient for primary producers in freshwater and marine ecosystems and contributes critically in regulating carbon cycle both at local (watershed) and global scale (land-ocean-atmosphere continuum). Hydrological processes, including groundwater fluxes and water circulation between surface and deep peat layers strongly influence silicon dynamics. Understanding local peatland hydrology is therefore essential to assess the role of peatlands as filters controling continental Si exports. Despite this central function, groundwater-peatland interactions remain poorly understood, limiting our ability to quantify peatlands’ contribution to global Si fluxes.
In this context, this study investigates how peatland hydrology, and particularly aquifer-peatland connectivity, shapes the dynamics of dissolved silicon within a temperate peatland system.
We implemented an integrated field-based approach, relying on long-term hydrological data collected hourly since 2008 and monthly hydrochemical measurements acquired since 2014, providing a robust framework to investigate peatland control on dissolved silicon fluxes. This was conducted at La Guette peatland, a lowland temperate peatland in the Sologne region (France) and part of the SNO Tourbières long-term observatory network. Paired surface and deep piezometers were installed both upstream and downstream of the peatland allowing for investigation of vertical, lateral and temporal variability in water and solute dynamics. Hydrological analyses based on water balance calculations are combined with a multi-tracer geochemical approach to assess groundwater contribution. Silicon dynamics are further examined using concentration-isotope ratio (DSi-δ³⁰Si) relationships to disentangle biological and hydrological controls.
Preliminary results indicate the presence of groundwater inputs originating from the surrounding sandy aquifer, supporting the characterization of the La Guette peatland as a groundwater-dependent ecosystem. The data reveal vertical and lateral gradients, as well as temporal variability in both DSi concentrations and δ³⁰Si signatures. Concentration-isotope ratio relationships suggest a seasonal shift in dominant controls, with biologically influenced silicon dynamics during spring and summer and hydrologically driven processes during autumn and winter. Together, these observations provide new insights into the links between peatland hydrology and silicon dynamics and highlight the need to further investigate groundwater-peatland interactions when assessing peatland contributions to continental biogeochemical fluxes.
How to cite: Le Fer, L.-M., Moquet, J.-S., Guimbaud, C., Freslon, N., Deschamps, N., and Bouchez, J.: Peatland hydrology shapes dissolved silicon dynamics across peat profiles, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-13675, https://doi.org/10.5194/egusphere-egu26-13675, 2026.
Groundwater-influenced, nutrient-rich sloping fens are characteristic of northeastern Finland, where they are affected by both groundwater discharge and surface water inputs, including spring floods. This study examines the geochemical composition of peat pore water in Puukkosuo, a sloping fen underlain by carbonate bedrock, with two objectives: (1) to evaluate the influence of groundwater discharge on peat hydrogeochemistry, and (2) to compare hydrochemical and geochemical signatures with those of northern boreal peatlands underlain by different bedrock types.
The 3D structure of the peatland was modeled to understand flow paths within the Peatland basin (Åberg et al. 2025). Four peat cores were collected to characterize peat composition, humification, and geochemistry, alongside pore water samples from the same locations (Erhovaara 2023). Porewater samples from three locations from different depths were analyzed for trace elements, major ion composition, pH, EC, TOC, TC, IC, NO3+NO2, NH4, Tot N, Tot P, stable isotopic composition of water and δ13C (DIC ) to assess groundwater and bedrock influence. Additional surface and groundwater samples were analysed for trace elements and majos ion composition, pH and EC as a reference.
High Ca and Mg concentrations, as well as high pH and EC in pore water indicate strong groundwater input, while elevated nutrient levels observed at the western edge of Puukkosuo primarily reflect surface runoff. Although the broader catchment lacks extensive carbonate deposits, the presence of carbonate bedrock beneath Puukkosuo, combined with its sloping morphology, demonstrates that groundwater flow paths significantly shape the hydrogeochemical conditions of the fen.
Erhovaara, S., 2023. Carbon accumulation and peat geochemistry in the Puukkosuo fen during the Holocene. MSc. thesis, University of Helsinki. 45 p.
Åberg, A., Nurmilaukas, O., Korkka-Niemi, K. & Kultti, S., 2025. Kuusamossa sijaitsevan Puukkosuon maatutkaluotaukseen perustuva 3D-mallinnus. Geological Survey of Finland. GTK Open File Work Report 40/2025. 24 p.
How to cite: Korkka-Niemi, K., Erhovaara, S., Kultti, S., Kuosmanen, N., and Åberg, A.: Hydrogeochemical Signature of Groundwater-Influenced Sloping Fen in the Calcareous Rich Northern Boreal Environment, Finland, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-21609, https://doi.org/10.5194/egusphere-egu26-21609, 2026.
Tropical peatlands, which cover 13–15% of the global peatland area, play a vital role in the global carbon storage, yet their key hydrological processes influencing carbon dynamics are not well accounted for in most land surface models. The Cuvette Centrale wetland of the Congo Basin is the world’s largest continuous tropical peatland area, which is governed by a complex hydrology. It is partly driven by river-peatland interactions and a spatially variable bimodal annual precipitation pattern across the Congo Basin, as well as by an unknown influence of deeper groundwater on the phreatic water levels (WL) in the peatlands. Accurate estimation of water and carbon dynamics for peatlands necessitates advancements in land surface models by incorporating peatland-specific modules to simulate key hydrological processes. In this study, we enhance the Noah-Multiparameterization (Noah-MP) land surface model to incorporate peatland hydrological processes, by including peat soil hydraulic parameters, microtopographic integration, and new runoff and evapotranspiration schemes. The peatland-specific scheme and the default TOPMODEL scheme of Noah-MP (further called “reference”) are applied across the Cuvette Centrale domain using two different meteorological forcing datasets, MERRA-2 and MERRA-2 with CHIRPS precipitation. The simulations were evaluated using in-situ WL observations and terrestrial water storage anomaly (TWSA) observations from the GRACE and GRACE-FO missions. Preliminary evaluation with in-situ WL observations shows overall improvement for peatland-specific simulations compared to the reference. Especially for the experiment with CHIRPS precipitation, which generally showed the better skill metrics, the new peatland scheme shows 5.79% increase in correlation and 86% reduction in RMSE compared to the reference driven by the same forcing. The terrestrial water storage anomalies simulated by the peatland-specific model in conjunction with altimetry-based river water storage estimates, also show an increased anomaly correlation with GRACE mascon-derived water storage anomalies. By more realistically representing the peatland hydrology, this work lays the groundwork for improved predictions of tropical peatland carbon–water interactions, with future scope for coupling with a river-routing model to better understand the peatland-river interactions for the Congo peatlands.
How to cite: Chakraborty, A., Willems, P., De Lannoy, G. J. M., Mocko, D. M., Kumar, S. V., He, C., Nkaba, L., Crezee, B., Tshimanga, R. M., and Bechtold, M.: Advancing tropical peatland hydrology in the Noah-MP land surface model, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15064, https://doi.org/10.5194/egusphere-egu26-15064, 2026.
Shallow peatlands (average peat depth <40 cm) exhibit differences in key structural and hydrophysical characteristics from their deeper counterparts. They generally exhibit higher bulk density, lower organic matter content, lower hydraulic conductivity, greater tree density and height, and lower microtopographic complexity. These differences mediate the strength of ecohydrological feedback mechanisms, generally resulting in weaker mechanisms with a regulatory function (negative feedbacks) and stronger mechanisms that have a destabilizing function (positive feedbacks). Ultimately, these differences in peatland form and function result in systems that have a profound contrast in ecohydrological behaviour, exhibiting more frequent water table fluctuations, longer periods when the water table is both above and below the optimum depth, and shorter periods where the surface soil water tension is in equilibrium with the water table. We hypothesize that this leads to greater decomposition, lower productivity, and thus a smaller net carbon sequestration. As a consequence, these shallow peatlands are disproportionately more vulnerable to disturbances, such as drought and wildfire. This can perpetuate a cycle of vulnerability, which prevents shallow systems from obtaining the depth associated with greater resilience. By studying these vulnerable systems we can learn what environmental conditions herald a regime shift associated with a loss of resilience and a degrading peat carbon stock.
How to cite: Sutton, O., Furukawa, A., Simone, K., Verkaik, G., Moore, P., Clark, A., Fallas, R., Moore, M., Sherwood, E., Broyd, R., Van Huizen, B., Morris, P., and Waddington, J. M.: Peat depth as a control on peatland ecohydrological resilience, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-4090, https://doi.org/10.5194/egusphere-egu26-4090, 2026.
Peatlands play a critical role in the global carbon cycle, with water level dynamics strongly controlling their function as carbon sinks or sources. While process-based models are commonly used to simulate peatland hydrology, the potential of data-driven approaches remains largely unexplored at large spatial scales.
Here, we assess the capability of a Long Short-Term Memory (LSTM) model to simulate daily water level in natural northern peatlands (40°N–75°N), trained on a diverse set of in situ water level observations. Model performance is evaluated against the same in situ water level observations using a strict block-wise cross-testing scheme. Furthermore, model performance is benchmarked against simulations from NASA’s Catchment Land Surface Model with peatland modules (PEATCLSM).
The LSTM model demonstrates improved agreement with in situ water level observations compared to PEATCLSM in terms of root mean square difference and bias, while the PEATCLSM exhibits higher spatial and temporal correlation with the in situ observations. Feature importance analysis indicates that the LSTM model captures key hydrological controls on water level dynamics, with precipitation and reference evapotranspiration emerging as dominant drivers, followed by leaf area index and snow water equivalent.
The lack of sufficient in situ water level observations for model training, both in terms of record length and spatial coverage across peatland sites, restricts the development of a model with additional input variables that could enhance performance. Despite these limitations, the LSTM model shows spatial patterns consistent with the process-based model, supporting its reliability. These findings highlight the potential of deep learning approaches such as LSTM-based modeling to complement traditional process-based modeling of peatland hydrology. Future improvements will depend on collaborative data sharing to enhance training datasets and support informed climate and environmental decisions.
How to cite: Van Nieuwenhove, H., Bechtold, M., Lhermitte, S., Desai, A., and De Lannoy, G.: Benchmarking a long short-term memory model against a process-based model for peatland water level dynamics, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10883, https://doi.org/10.5194/egusphere-egu26-10883, 2026.
The use of testate amoeba as a palaeohydrological indicator in Norwegian wetlands is very limited and mainly focused on salt marshes with non-existent studies in this field in boreal, Atlantic, and mountain peatlands. This study could be the basis for additional future work on understanding past hydrological dynamics in Norwegian mountain peatlands by qualitatively or quantitatively approaches of reconstruction. The study areas included: 1) a more ombrotrophic bog located in Upsete at around 800 m.a.s.l facing a more Atlantic climate and near the treeline, and 2) a poor fen in Øynan, located at a higher elevation site (1100 m.a.s.l) in the low alpine region with a more continental climate in the southern mountain area of the country. To isolate the testate amoebas, we followed a water-based method and under the microscope, we counted a minimum of 150 testates in around 30 samples per peat profile for each of the two sites. Among the species of Testate amoebae that indicated wetter conditions, we found Archerella flavum, Centropyxis discoides, Hyalosphenia papillo and Heleopera petricola as the most representatives. There are two marked periods at Upsete, where wetter indicator species appear: between 9500 and 10500 yrs BP and between 3000 and 4500 BP. Similarly, at the Øynan site, the periods that indicated wetter conditions correspond to 8000 – 9000 yrs BP and 3500 – 5000 yrs BP. At the same time, the wetter periods indicated by testate amoebae analyses also match the periods of higher carbon accumulation that was also recorded in the laboratory.
How to cite: Quintana, C., Bjune, A., Seddon, A., and Lee, H.: Testate amoeba as a palaeohydrological indicator in mountain peatlands in the south of Norway , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-13850, https://doi.org/10.5194/egusphere-egu26-13850, 2026.
Peatlands are essential for biodiversity conservation in wetland ecosystems and for mitigating global warming through carbon storage. Given the importance of peatlands, conservation and restoration efforts have been undertaken worldwide. This study examined the Kushiro Mire in Hokkaido, Japan, where river channel straightening in the 1980s led to wetland degradation, including the conversion of the mire to alder stands and the loss of the wetland landscape. In the 2010s, a nature restoration project was implemented to restore the river meander of the Kushiro River. In this study, tree-ring core samples were collected from alder trees growing around the restored river meander area. They were used to estimate tree age from the number of tree rings and annual growth from the ring width. The effects of river restoration on alder growth were then assessed based on changes in growth. Eight alder tree-ring surveys were conducted at sites where tree-ring conditions were expected to differ. At each site, five to six trees exhibiting typical growth conditions were surveyed. Tree-ring analysis revealed that the average tree ages at the eight sites were roughly divided into two groups: 25 and 35 years, with a difference of approximately 10 years. Both groups had entered and expanded within the mire following the 1984 river channel straightening, but before the river meander restoration was completed in 2011. At survey points near the restored meandering river channel, there was a statistically significant decrease in tree-ring growth following restoration relative to pre-restoration conditions. Conversely, at survey points near the former straight river channel, there was a significant increase in tree-ring growth following restoration. Flood inundation simulations with pre- and post-restoration of the river meander implied an increase in sediment thickness after restoration at survey points near the former straight river channel. Meanwhile, at survey points downstream of the restored meandering river channel, flood-induced sediment deposition was implied to decrease. The simulation results indicate that flood-induced sediment inflow into the mire could alter nutrient distribution, contributing to alder growth.
How to cite: Miyamoto, H., Nemoto, Y., and Oishi, T.: Tree-ring analysis on the alder tree growth in a river meandering restoration site of the Kushiro Mire, Hokkaido, Japan, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-6932, https://doi.org/10.5194/egusphere-egu26-6932, 2026.
Recent findings revealed that alpine peatlands are more spatially extensive than previously assumed, reinforcing their importance for carbon storage in alpine ecosystems. Alpine peatlands share certain characteristics with northern peatlands: they have a short growing season, strong seasonality, and are snow-covered for 6 - 9 months per year. While arctic and boreal peatlands are known to emit large amounts of greenhouse gases (GHG), it is still largely unknown to which extent alpine peatlands show different GHG dynamics under climate change and how this links to abiotic and biotic differences like in radiation, soil properties, hydrology and plant community composition.
In a multidisciplinary study, covering geohydrology, biogeochemistry, microbial ecology, and plant science, we investigate an alpine peatland in Vorarlberg, Austria located at 1670 m a.s.l. altitude on a slight slope of a plain surrounded by mountains up to 2416 m a.s.l. Methane flux measurements with static chambers showed a strong seasonal variation with a surprising switch from methane uptake in certain locations in spring to methane emissions in summer, potentially indicating a large variation in redox conditions with the seasons due to changes in the hydrology. In winter, when the area is covered by >1 m of snow, the sampled alpine peatland remains partly uncovered due to the continuous input of 5°C spring water. This creates a unique environment in which microbial carbon cycling continues at a higher rate than at nearby sites and leads to ongoing methane emissions throughout winter. The strong methane emissions in summer depended strongly on day (high) and night (lower) and short-term weather in the days before/during the measurements, with higher emissions during hot, dry periods compared to colder, rainy periods. In addition, we observed a very large spatial variation, even within the 1 m2 scale. This large spatial variation in GHG emissions is supported by a large variation in soil organic carbon and total nitrogen content between locations within the peatland site, as well as variations in the plant community, and seems to be linked to groundwater flows which will be further analysed in upcoming field campaigns.
How to cite: van Grinsven, S., Kunz, S., Jueterbock, F., Cirpka, O., Drews, R., Oelmann, Y., Monte, I., Mason-Jones, K., Zarfl, C., Muehe, E. M., Streck, T., and Kappler, A.: The influence of local hydrology and seasonality on microbially-mediated methane emissions from a sloping alpine peatland, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-6976, https://doi.org/10.5194/egusphere-egu26-6976, 2026.
While patterned pools along the crest of northern raised bogs are surface features, their underlying geologic structure has been shown to influence local hydrology and, by extension, biogeochemistry. Beneath these pools, pore spaces accumulate biogenic gases, for which production depends on the availability of labile carbon. Some of these gases are released via ebullition, a bubble-transport mechanism by which gases migrate through the peat column and into the atmosphere. Our team targeted open-water pools in Caribou Bog, Maine (U.S.A.), to capture differences in ebullition and identify contrasts in dissolved methane and carbon dioxide. Distinct sites were selected for comparison: [1] on-esker sites, underlain by permeable glacial deposits, that locally form near-surface ridges, and [2] off-esker sites, underlain by a hydraulically confining glaciomarine clay, that blankets much of the peatland basin. Ebullition recorded in custom-built floating gas traps showed a fivefold increase in collection at the on-esker site. Gas chromatography analysis of sampled ebullition revealed methane concentrations ≥4000 ppm at sites proximal and distal to the esker transect. At both locations, headspace-equilibrated concentrations of dissolved methane in pools surged by two orders of magnitude, coinciding with drops in atmospheric pressure below 101.25 kPa. This suggests that falling surface pressure triggers discrete pulses of gas migration from over-pressured pore spaces. Further, dissolved concentrations of methane in water from nested wells confirm active methanogenesis in the catotelm, down to nine meters depth. Within the peat column, gas accumulation and migration were investigated over a 12-day period in August using repeated common-midpoint ground-penetrating radar (GPR) surveys. Coupling electromagnetic wave velocities with the complex refractive index model, 1D models of gas content were produced for off- and on-esker locations. These gas content estimates indicate that biogenic accumulation is, on average, 5–7% greater at sites along the beaded esker transect. Combined, these results suggest that underlying esker structures act as localized hot spots for biogenic gas production, storage, and enhanced ebullition.
How to cite: Hess, R., Moore, H., Bertolet, B., Comas, X., Reeve, A., Ntarlagiannis, D., and Slater, L.: Estimates of biogenic gas dynamics in a northern raised bog inferred from hydrogeophysics, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-13359, https://doi.org/10.5194/egusphere-egu26-13359, 2026.
Many countries in the world are trying to reduce their carbon emissions to minimize climate change, as described in the Paris Agreement of 2015. Alongside well-known, worldwide sectors contributing to emissions such as transport, industry and mining, drained peatlands can substantially contribute to national emission such as in The Netherlands. The organic matter in peat is susceptible to decomposition; the breakdown of organic tissue and transformation into carbon dioxide, methane and N2O gas by microbes. Oxic decomposition with oxygen from the air occurs above the groundwater table, while anoxic decomposition occurs in the absence of oxygen above and below the groundwater table. Oxic decomposition is the more optimal method of organic matter breakdown, resulting in faster decomposition rates and higher emissions. To evaluate if yearly emission reduction targets are achieved, models are used to estimate the amount of carbon emissions originating from peat meadow areas. Although many types of models with a wide range of complexities are used, a key element is usually that the groundwater level determines the boundary between the oxic and anoxic decomposition zones. Therefore, a thicker oxic zone will result in more emissions if the other conditions remain stable as more organic matter is exposed to oxygen. However, oxygen intrudes the soil by diffusion and advection. The oxygen intrusion takes time and is limited by pore connectivity and temperature, which vary with depth. Thus, oxygen intrusion on a yearly timescale is likely not linear with the yearly average groundwater level, but depends on the peat type, peat profile and temperature conditions. The model used to estimate the Dutch national carbon emissions applies a continuous linear increase of carbon emissions with decreasing groundwater levels that fits with the Dutch observed emissions. However, countries like Germany, and Denmark favor an S-shaped relationship that describes maximum emissions below a certain groundwater depth.
This research uses a dedicated process model to further investigate this relationship between groundwater level and emissions. Specifically, we look at the relationship between oxygen intrusion into the peat soil and carbon emissions. We use a model that is calibrated for a drained peatland under intensive agricultural use. We calibrated on observed CO2 emissions and soil redox conditions. Subsequently, we vary the oxygen diffusion coefficient in the model, which is likely to depend on decomposition degree, clay fraction and peat compaction. We find that in simulations with limited oxygen intrusion deeper summer groundwater tables do not result in equally more oxygen in the soil. Oxygen intrusion trails the groundwater depth, and this intrusion delay is explained by diffusion limitations and oxygen consumption by microbes near the surface. This limits the potential for decomposition at larger depths during deep groundwater tables. Consequently, we find that the increase of emissions with decreasing yearly average groundwater levels follows the well-known S-curve for peatland with a low oxygen diffusion into the soil or deep groundwater levels. This result is an important step in our understanding of observed emissions for different peat types and groundwater management strategies.
How to cite: van Elderen, P. and van der Velde, Y.: Exploring oxygen intrusion as explanation for observed emission differences in Dutch peatlands., EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17181, https://doi.org/10.5194/egusphere-egu26-17181, 2026.
Posters on site: Fri, 8 May, 14:00–15:45 | Hall A
Soil moisture is a key regulator of greenhouse gas emission and other biogeochemical processes as well as of land management options in peatlands and other organic soils. Water table depth is often used as a proxy for soil moisture in these systems. However, it shows no consistent relationship with volumetric water content (VWC) or water-filled pore space (WFPS).
Non-destructive measurements of soil moisture with a high temporal resolution can be obtained using an electromagnetic sensor to determine the relative dielectric permittivity (ε), which is then converted to VWC through calibration functions. As the relationship between ε and soil moisture is exponential, precise measurements of ε are essential, particularly for peat-specific calibrations where VWC may exceed 80%. While the accurate determination of ε has been extensively studied within the range typical of mineral soils (< 40), sensor performance at high ε values (> 40), which are characteristic of organic soils, has hardly been investigated. Reliable soil moisture sensors are, however, crucial for accurately quantifying the effects of VWC and WFPS on greenhouse gas exchange, as well as for assessing the trafficability of organic soils.
Our investigation aimed to examine the suitability of various commercially available soil moisture probes with five different measurement methods across the entire ε range. To this end, we tested 14 different probes, each with three sensor replicates. The experiment was conducted under laboratory conditions using different reference solutions with defined values between 1 < ε < 80. No soil was used here. In addition, the influence of different electrical conductivities (0 to 800 μS cm-1) on the measurement accuracy of the sensors was also investigated.
Although the 14 probes operated with different measurement methods, no differences in overall sensor performance could be attributed to this. The results showed that four of the sensors tested measure very reliably and accurately between 40 > ε < 80 and are therefore recommended for use in organic soils. Five further sensors are conditionally usable, and the rest are not suitable for accurately measuring soil moisture in organic soils. Intersensory variability was found to be highest for the latter probes. Additionally, about half of the 14 sensors tested showed increasing uncertainties at elevated electrical conductivities up to 800 μS cm-1. Soil-specific calibrations are still required to ensure reliable measurements. However, our results offer guidance for evaluating sensors based on their accuracy and performance and to choose suitable sensors for soil-specific calibration.
How to cite: Säurich, A., Dettmann, U., and Tiemeyer, B.: In situ soil moisture sensing in organic soils: what works?, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8873, https://doi.org/10.5194/egusphere-egu26-8873, 2026.
The water table depth (WTD) is one of the main drivers for greenhouse gas (GHG) emissions in peatlands. Peatlands act as long term carbon sinks when the water table remains close to the soil surface, whereas drainage typically leads to substantial GHG emissions. Hence, detailed spatial water table information with high temporal resolution is a crucial requirement for evaluating restoration success and supporting practical management decisions. Combining continuous in situ WTD measurements with remote sensing approaches can open an innovative way of deriving hydrological information for applied peatland management und restoration. However, few studies combine near real time in situ loggers with remote sensing to generate spatially continuous and frequently updated water table products for operational monitoring.
Here we present an end-to-end workflow for automated water table mapping, that couples continuously transmitted in situ water level measurements and high-resolution terrain information by UAV LiDAR with immediate data processing. A network of water level loggers transmits measurements every 30 minutes automatically to a central database using the public cellular network. Additionally, UAV LiDAR point clouds are acquired twice a year using a Zenmuse L2 sensor, suitable for the use in densely vegetated areas. Ground points are classified using the cloth simulation filter to minimize residual canopy artefacts to generate a 0.25 m Digital Terrain Model (DTM) to capture peatland microrelief. The generated DTM ist then validated against RTK GNSS ground truth points to quantify the vertical accuracy and ensure the reliability of the LiDAR data. The WTD is computed by referencing gauge water levels to the DTM. Spatially continuous water level maps are produced using a regression kriging approach that exploits the strong dependence of water level on relative surface elevation. Model performance is evaluated by using leave-one-out cross-validation across the gauge network, allowing a direct comparison of LiDAR based against public DTM based WTD and quantifying uncertainty in derived water level maps.
Initial results suggest that the LiDAR based DTM reduces elevation bias compared to public DTMs and yields more consistent interpolated WTD dynamics, especially in heterogeneous areas. Furthermore, by linking near real time logger data with high resolution DTMs, the workflow enables a reproducible, automated delivery of regularly updated WTD maps for operational use to support water management, restoration planning and the establishment of paludiculture. In addition, these products provide hydrological inputs for proxy based GHG emission assessment, e.g. supporting GEST (Greenhouse Gas Emission Site Types) approach for baseline emission estimates in strongly drained areas and for tracking changes during the transition after rewetting. The output can contribute to monitoring, reporting and verification of workflows, supporting certification schemes such as voluntary carbon crediting.
How to cite: Husting, T., Grenzdörffer, G., Rossa, H., Ahlgrimm, T., Bergheim, M., Jurasinski, G., and Pönisch, D. L.: High resolution automated water table mapping using UAV LiDAR terrain data and near real time water logger measurements, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19747, https://doi.org/10.5194/egusphere-egu26-19747, 2026.
Peatlands store approximately one-third of the world’s soil carbon, making accurate mapping of surface water dynamics essential for understanding their role in the global carbon cycle. Global Navigation Satellite System - Reflectometry (GNSS-R) provides an effective means for long-term, large-scale monitoring of surface water, particularly in densely vegetated tropical peatlands due to the strong penetration capability of L-band signals.
In this study, we map inundation over the Congo Basin using data from the CYGNSS mission. The training, validation and testing data consist of 559 temporally sparse inundation fraction samples (March 2017-August 2021) derived from water table depth observations at four in-situ stations combined with information on spatial variability of ground elevation. Multiple features are extracted from CYGNSS delay–doppler maps and their retrieved reflectivity, including signal-to-noise ratio (SNR), statistical moments (mean, variance), and waveform-based indicators such as leading-edge slope (LES) and trailing-edge slope (TES). These GNSS-R features are combined with auxiliary variables including NDVI and precipitation and are used to train machine learning models (Random Forest) for estimating inundation fraction.
Model performance is evaluated using a leave-one-spatial-cluster-out cross-validation strategy to ensure spatial independence between training and testing data. The results demonstrate that models based on multiple CYGNSS features significantly outperform those using single features alone. At high inundation level, models based solely on CYGNSS tend to underestimate surface water coverage, whereas the inclusion of precipitation significantly reduces this bias and improves R² during highly saturated conditions. These findings highlight the strong potential of GNSS-R combined with machine learning for large-scale tropical peatland hydrological monitoring.
How to cite: Pan, Y., Bechtold, M., Cobb, A., Chakraborty, A., Ma, J., Nkaba, L., Tshimanga, R., Van Coillie, F., and Lambot, S.: CYGNSS based Mapping of Inundation Dynamics in Congo Peatlands Using Machine Learning, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-20351, https://doi.org/10.5194/egusphere-egu26-20351, 2026.
Understanding the subsurface structure and dynamics of peatlands, is key to understanding their role in ecosystem services and processes. Many existing methods are limited to capturing information about small surface areas, over limited time periods, and are labour intensive. Geophysical approaches have the potential to overcome some of these limitations.
We present the preliminary results of a project aiming to develop novel geophysical methods to image peat bogs in 3-dimensions and to monitor peatland health over time. We use seismic nodes for low-cost, non-invasive, continuous monitoring. A network of seven nodes has so far been deployed on an un-restored upland peatland setting in North East Scotland, with in situ waterloggers already established. Using ambient background noise (‘seismic interferometry’), we investigate how the seismic velocity changes over time as a proxy for groundwater changes, an important measure of peatland health. We further conduct an active seismic survey to assess peat thickness by combining surface wave dispersion with the natural ground resonance frequency, obtaining peat thicknesses of ~3.5m, comparable to depths measured using conventional peat probing. We also investigate the utility of other geophysical techniques to image peat structure and saturation, including Ground Penetrating Radar and Electrical Resistivity Tomography.
How to cite: Gilligan, A., Lythgoe, K., Murray, D., Parker, T., Atrz, R., and Naylor, M.: Monitoring peatlands with novel geophysical methods, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-21139, https://doi.org/10.5194/egusphere-egu26-21139, 2026.
Peatland hydrology strongly regulates ecosystem functioning, carbon storage, and vulnerability to disturbance. Although maritime peatlands along the Gulf of Saint Lawrence (eastern Canada) are generally considered fire-resilient due to high atmospheric moisture, recent severe fire seasons in surrounding boreal forests highlight the need to better understand how fire influences peatland hydrological and biogeochemical dynamics. Such understanding is essential for interpreting long-term palaeoecological records and assessing peatland sensitivity to ongoing climate warming.
In this multi-proxy study, we combine traditional palaeoecological proxies (testate amoebae, charcoal, pollen, and plant macrofossils), with geochemical analyses (XRF and FTIR) to evaluate the impacts of local and regional fires on a maritime raised bog near Baie-Johan-Beetz (Québec). We present preliminary high-resolution results from a short peat monolith (BJB-03) covering the last ~1100 years. The record captures distinct ecological and geochemical shifts, including lichen-Sphagnum transitions, changes in peat accumulation rates, and intervals of increased presence of macrocharcoal particles associated with variations in elemental composition, carbon content, and peat decomposition. Using FTIR, a novel method in peatland fire studies, we aim to detect highly oxidised, presumed pyrogenic carbon and to quantify the relative redox state of peat, linking these signals to disturbance events recorded in the sequence.
The monolith provides a detailed archive of environmental change during the last millennium, including the period surrounding the well-documented 2013 regional fire event. These preliminary results constitute the first stage of a broader project reconstructing fire–hydrology interactions over the past 7500 years in this region of Canada.
The study was supported by the National Science Center of Poland (no. 2024/35/O/ST10/02903).
How to cite: Halaś, A., Słowiński, M., Obremska, M., Roberts, H., Magnone, D., and Garneau, M.: Hydrological and geochemical responses of a maritime peatland to fire disturbance: preliminary multi-proxy results from eastern Canada, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-4974, https://doi.org/10.5194/egusphere-egu26-4974, 2026.
Recent Canadian wildfires have generated daily mean PM2.5 values nearly 10 times the World Health Organization recommended limits in urban centers. Northern peatlands present a unique risk to air quality conditions as they: (i) store globally significant quantities of belowground carbon (C) in peat, which may fuel multiyear fires; and (ii) are prone to smouldering combustion, an inefficient low-temperature reaction that produces more smoke with increased particulate matter than flaming combustion. The same mechanisms that allow C to accumulate also support the accumulation of other deposited elements, including arsenic, mercury, lead, and nickel. Historically, northern peatlands have been resistant to burning due to the high near-surface water content and low bulk density of peat; however, water table drawdown alters these ecological protections, rendering peatlands susceptible to increased wildfire frequency, severity, and areal extent.
The Hudson Bay Lowlands (HBL) of Ontario, Canada, represent one of the largest intact peatland complexes remaining on Earth, yet ~5,000 km2 has been claimed for mining of critical minerals. Dewatering practices required to facilitate mine development and operations can reduce the water table in surrounding peatlands by up to 75 cm. Drying at the soil surface and along the peat profile increases risk for wildfire ignition and subsequent smouldering combustion, potentially forming an additional potent source for smoke emissions and particulate matter while threatening HBL C stores. Therefore, the objective of this study was to estimate the impact of several mine dewatering scenarios on potential smoke emissions from the peatlands of HBL. We simulated the potential effect of mine dewatering on soil moisture profiles using Hydrus 1D with hydrophysical properties derived from HBL peat profiles. Hydrus 1D simulations were used to assess susceptibility to combustion and, consequently, estimates of smoke emissions based on antecedent weather conditions measured prior to wildfires in the study region.
Preliminary results suggest that wildfire vulnerability will increase, which will lead to greater smoke emissions as a direct result of drying from mining and infrastructure development. Furthermore, due to increased human activity, ignition sources will also increase, leading to peatlands that are both more vulnerable to severe burning and an increased risk of fires igniting.
Although the focus of this study has been on the HBL, this work can be applied to other peatland systems that may undergo drying scenarios in the future, be it from mining, climate change, or drainage. Northern landscapes that have traditionally been resistant to wildfire may not necessarily remain as such, and the implications for human health may be far-reaching, with potentially compounding effects of smoke and the additional toxic elements that may be released as a result of burning.
How to cite: Wegener, E., Moore, P., Sutton, O., Waddington, M., and Dieleman, C.: Where there's fire, there's smoke: estimating smoke emissions from Hudson Bay Lowland mining, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-6076, https://doi.org/10.5194/egusphere-egu26-6076, 2026.
Peatlands are globally important long-term sinks of carbon, however climate change-mediated drought is expected to threaten the integrity of their carbon sequestration function due to enhanced decomposition and moss moisture stress. Furthermore, the intensification of drought (or drainage) will also increase peat combustion loss during wildfire leading to peatland degradation and a potential ecosystem regime shift. Despite research developments on identifying ecohydrological early warning signals (EWS) of tipping points in other ecosystems (e.g., forests, grasslands), research on peatland EWS is lacking. There is an urgent need to identify EWS metrics to adequately represent the potential positive feedback between peatland carbon loss and climate change within Earth Systems Models. By establishing a suite of simple EWS metrics that can summarize an impending or ongoing regime shift, the uncertainty associated with climate change-mediated degradation can be reduced and the trajectory of the global peatland carbon stock more accurately projected.
In this poster presentation we aim to gain more insight into peatland ecosystem behaviour and the early warning signals that may be found in these systems. We present ideas on how to measure ecohydrological tipping points and explore simple metrics that may reveal when these tipping points have been exceeded and the implications this has for carbon storage and fluxes. Moreover, we review how alternate stable state and resilience theory can be applied to peatlands and we explore how ecohydrological modelling and water table time series analysis can be used to identify what environmental conditions herald a peatland regime shift.
How to cite: Waddington, M., Larsen, L., and Sutton, O.: Identifying Ecohydrological Early Warning Signals of Peatland Destabilization, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7270, https://doi.org/10.5194/egusphere-egu26-7270, 2026.
Drained peatland forests cover a substantial fraction of boreal landscapes and are increasingly exposed to drought under a warming climate. After drainage, a mor humus layer has gradually developed on top of the peat—these sites are called transformed drained peatlands. This transformation fundamentally alters soil hydraulic properties and may increase drought sensitivity by weakening hydraulic connectivity between soil layers. However, the hydrological role of the mor layer and its impact on rootzone moisture availability remains poorly represented in current peatland ecohydrological models.
This study investigates how the mor layer regulates soil moisture and water table dynamics during dry periods. We compare the soil moisture and water table dynamics of a mor–peat profile using three different hydrological modelling approaches: i) a hydrostatic equilibrium model for the whole profile, ii) a mor-layer bucket model coupled to peat in hydrostatic equilibrium, and iii) a full 1D numerical solution of the Richards equation.
Preliminary results indicate that the mor layer can substantially modify near-surface soil moisture during drying events by limiting upward capillary flow from deeper peat layers. This hydraulic decoupling leads to faster topsoil drying and altered soil moisture profiles compared to simulations with an assumption of hydrostatic equilibrium. On the other hand, the drying mor layer rapidly starts to restrict evapotranspiration and protects water storage in the underlying peat. These effects are most pronounced during prolonged summer droughts, when evapotranspiration demand is high and capillary upflux becomes critical for sustaining root-zone moisture.
The proposed improvements to the description of hydrological interactions within the mor–peat profile advance process-based simulation of drought responses in transformed peatland forests. The results contribute to a better mechanistic understanding of soil moisture dynamics under meteorological extremes and provide a foundation for assessing drought risk and adaptive water management strategies in peatland forestry.
How to cite: Rantalainen, E., Palviainen, M., Koivusalo, H., Suominen, J., Koponen, H., and Laurén, A.: Progression of Drought in the Mor–Peat Profile of Transformed Drained Peatlands—a Modelling Study, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-9708, https://doi.org/10.5194/egusphere-egu26-9708, 2026.
Organic soils such as peatlands, which form through many years of accumulation of organic matter under waterlogged conditions provide many ecological benefits such as storing ca. 30 % of the global soil carbon, acting as a sink for many nutrients and pollutants, playing a crucial role in the water cycle, and hosting numerous species of plants and animals. Drainage of many peatlands for agriculture and other activities have contribute to approximately 7 % of the total anthropogenic greenhouse gas emissions in the European Union. The conservation and management of the peatland require in depth knowledge of the hydrological processes, water chemistry, and other controlling factors. This study focuses on the geochemical changes encountered while rewetting a fen peatland located in the northeastern part of Germany that is planned for installation of photovoltaic elements, aiming to make the rewetting both ecologically and economically viable. Rewetting of peatland that has undergone years of drainage-induced degradation can result in the aqueous release and transport of trace elements and nutrients, thereby deteriorating the quality of downstream groundwater. We conducted rewetting column experiments aiming to understand the geochemical processes and reaction pathways that can be encountered while rewetting degraded peat bodies. As part of this experiment, three highly degraded peat samples and one moderately degraded peat sample of 30 cm thickness were collected from the study site that represent three different water level situations and are simulated to undergo rewetting using peat pore water obtained from the field. The columns were supplied with circulating water at a flow rate of 8.3*10-5L*s-1, at 10 °C, representing groundwater temperature, for a period of 100 days. Regular sampling of peat water from the column reservoir for major and trace element analyses as well as in-situ parameters measurements have contributed to understanding hydrogeochemical mechanisms and evolution. In addition, microbial analysis of the peat water and soil, before and after the rewetting experiment, will contribute insights into the influence of bacteria on the geochemical processes taking place under anoxic conditions. Analysis of the peat column after the rewetting experiments will provide crucial information on the changes of the peat geochemistry and element mobility. The experimental approach combined with geochemical modelling will enhance the understanding of the alterations in the peat water chemistry and estimate the potential impacts on downstream water resources quality.
How to cite: Johnson, J., Ortmeyer, F., and Banning, A.: Experimental Study of Geochemical changes in a Degraded Fen Peatland during Rewetting, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-14498, https://doi.org/10.5194/egusphere-egu26-14498, 2026.
Peatland restoration using cell bunding relies on low peat embankments to retain target water levels, yet seepage through such peat bunds is difficult to predict because hydraulic conductivity varies over orders of magnitude and is strongly spatially structured. This study quantifies steady-state seepage uncertainty for a representative two-layer bund system at All Saints Bog (Ireland) using a random finite element framework. Layer-specific conductivity statistics were obtained from laboratory tests on undisturbed peat cores and represented as lognormal in physical space. Spatial heterogeneity was modelled using anisotropic Gaussian random fields generated by the spectral representation method within a 3 × 3 factorial design, spanning three variance levels and three correlation-scale settings for both bund and base layers. For each group, ten independent realisations were mapped element-wise in a PLAXIS 2D seepage model and solved under realistic operational heads from 0.00 to 0.35 m. Discharge was extracted at multiple vertical control sections and at the downstream toe, and analysed using ensemble seepage rate – head (Q–H) relationships, local sensitivity, variance decomposition, and exceedance statistics. Seepage rate increased nonlinearly with head, and uncertainty amplified towards the seepage face toe, where coefficients of variation at H=0.35 m ranged from 8% to 36% across groups (compared with 6% to 21% mid-bund). Upper-tail behaviour strengthened with increasing variance and longer correlation scales; at the toe, Q95 and Q99 at H=0.35 m reached 8.60×10−4 and 1.07×10−3 Ls−1m−1, respectively. The results show that exceedance-based seepage quantiles provide more decision-relevant estimates than mean values alone and offer a practical basis for reliability-informed bund design. These results can also be used to help modelling the overall performance of such peatland bund network used in the restoration of raised bogs.
How to cite: Ahmad, S., Igoe, D., and Regan, S.: Stochastic Modelling of Seepage through Peat Bunds used to Rewet Cutaway Raised Bogs in Ireland, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19121, https://doi.org/10.5194/egusphere-egu26-19121, 2026.
Peatlands are groundwater-dependent ecosystems, even when they overlie less conductive glacial sediments. Their resilience relies on stable groundwater regimes, yet deep drainage from underground mining can disrupt these systems and amplify the changes in the climate. Selisoo bog (NE Estonia), a Natura 2000 raised bog, has been monitored since 2010 to track hydrological responses to adjacent underground oil-shale mining. The monitoring network spans from the bog margins to its centre and includes measurements of piezometric heads in peat, the underlying glacial sediments, and bedrock beneath the peatland. Analyses have revealed statistically significant declines in piezometric heads in peat at the bog margins and in surrounding drained peatland forests, driven by increased vertical hydraulic gradients and seasonal fluctuations, while the central part of the bog remained largely unaffected.
In 2021, restoration measures were introduced by damming forestry ditches along the eastern side of the bog to reduce lateral outflow. The second phase of the restoration was carried out in 2024. Here, we present data from the start of monitoring through the end of 2025, including the restoration works carried out and an “unusually” humid summer in 2025.
Our findings underline the need for an integrated monitoring of peatland–aquifer connectivity when issuing mining permits and designing restoration strategies for peatlands adjacent to mining areas. They also highlight how growing climatic variability interacts with human-induced drainage, affecting the hydrological regime of a raised bog in such hydrogeological settings. The continued long-term monitoring also enables us to assess the effectiveness of restoration and evaluate whether these measures can mitigate the effects of declining groundwater levels and rising vertical gradients.
How to cite: Paat, R., Kohv, M., and Jõeleht, A.: Peatland–Aquifer Connectivity: Insights from a Raised Bog Resilience to Mining-Induced Drainage, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-9264, https://doi.org/10.5194/egusphere-egu26-9264, 2026.
In peatland restoration, successful restoration of hydrology is the main prerequisite for restoring the targeted plant community and ecosystem functioning. In peatlands, groundwater influence may enhance restoration success by providing a stable water supply. Moreover, groundwater often supports habitat types of high floristic value.
The objective of this study was to assess the potential groundwater influence within the Finland’s national monitoring network for restored peatlands. The work is a part of the ECO-WADE project (Enhanced Understanding of Carbon and Groundwater Dynamics in European Peatlands and Their Related Ecosystem Services), funded by the Research Council of Finland and the EU Water4All partnership.
Potential groundwater influence was first identified using open-access geospatial datasets. The study utilized geological data such as information on glaciofluvial formations, which can be significant sources of groundwater for downstream peatlands. Mapped groundwater discharge locations, such as springs, and catchment areas and surface-water flow paths delineated using digital elevation models were used to study the potential connections. Groundwater influence was also examined using open satellite datasets. During the warm summer season, groundwater discharge areas appear cooler than their surroundings in thermal imagery. In winter, under snow-covered conditions, these areas may appear as patches with reduced or absent snow cover.
The geospatial and remote sensing analyses were compared with porewater temperature and water quality parameters (e.g., electrical conductivity, pH) collected from monitoring sites to determine whether these indicators also reflect groundwater influence.
The results showed the monitoring sites potentially fed by groundwater. Information derived from open geospatial and remote sensing datasets can support and guide the assessment of hydrological restoration success and help identify restoration sites with the potential to sustain valuable habitat types.
How to cite: Lindsberg, E., Ikkala, L., Korkka-Niemi, K., Päkkilä, L., Marttila, H., Kareksela, S., and Maanavilja, L.: Geospatial Assessment of Groundwater Influence at Finland’s National Monitoring Network for Restored Peatlands, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-13208, https://doi.org/10.5194/egusphere-egu26-13208, 2026.
