Maria Grodzka-Łukaszewska

Climate change is an obvious driver of changes in water regimes in Polish rivers. However, human interventions in catchments strongly magnify its negative effects. One of the most visible consequences is the increasing intermittence of rivers that only a few years ago flowed throughout the year. In Poland, river intermittence is a relatively new phenomenon. Smaller rivers now disappear for significant parts of the year due to prolonged hydrological droughts.Within the project “Intermittent rivers of Central Europe: Identifying threats to protection goals and biodiversity for efficient nature conservation and climate-proof environmental management”, we analysed all available Polish records of daily discharges and identified 22 gauging stations where extremely low or zero flow occurred at least once during the observation period.We observed strong temporal unevenness in the occurrence of low-flow events, suggesting that gradual climatic change alone may not fully explain the development of river intermittence. Indeed, when compared with land-cover changes derived from successive CORINE Land Cover maps, some stations revealed sudden increases or decreases in the frequency of low-water events. Although this pattern was not observed for all analysed intermittent rivers, it may provide further evidence that unsustainable water management practices in catchments amplify the effects of climate change.

This study examines the condition and environmental impact of abandoned peatland quarries in Lithuania. Using spatial data and field investigations, we identified 33 abandoned peat quarry sites covering over 3,854 ha, which were abandoned between 1940 and 2020. Detailed field assessments were conducted at each abandoned peatland quarry to evaluate the peat depth, pH, carbon-to-nitrogen ratio, decomposition, water table levels, and wood volume. Despite past extraction, many sites still contain substantial peat layers along with significant carbon and water storage potential. However, ongoing drainage continues to drive peat loss and carbon dioxide emissions. We estimate that peat loss from extraction totaled 77.5 million m3, which equates to a current value of €899 million in revenue. Nonetheless, the abandoned peatland quarries still host peat deposits ranging from 0.5 m to 2 m in depth. The drying and degradation of the peatlands has also reduced the water storage capacity across the 33 study sites. This loss is estimated at approx. 62 million liters of water, which equals approx. €33 million. This substantially affects local hydrology and increases the vulnerability to drought, fire, flood and natural biodiversity. Carbon emissions from drained peat soils are also substantial. We estimate approx. 14.2 t CO2 emissions equaling €813 million were lost from peat extraction alone. These emissions are often unreported if such areas are classified simply as “forests.” Our findings highlight the need for active restoration, particularly rewetting, to stop further degradation. Rewetting would reduce emissions, improve water retention, and support biodiversity recovery while offering clear opportunities to align peatland restoration with EU climate and nature goals.

The paper deals with the application of the geophysical method for the investigation of the near-subsurface fragile hydrological environments. The study delivers geophysical measurement data performed in the Rospuda wetlands located in north-eastern Poland. The measurements were carried out by means of the electrical resistivity imaging (ERI; also called electrical resistivity tomography, ERT) method, which so far has never been used in this region of the river Rospuda peatland valley. The ERI data were collected in a single survey campaign in November 2022 to account for the wet season. During the campaign, two ERI profiles were measured. The aim of the fieldwork was to provide material for illustration of the arrangement of geological layers creating the wetland. A data repository contains detailed descriptions for each survey site. The study revealed a strong interaction between groundwater, characterized by a thick sandy aquifer, and surface water. In this system, surface present peat constitutes the dominant soil component within the contact zone between groundwater and surface water (with drainage river type). Variations in this relationship will have a direct impact on peat stability and associated hydrological processes. The water-saturated peat electrical resistivity zone (10–40 Ω m) has a thickness ranging from a few to several meters at a maximum (the highest thickness of peats is present near the Rospuda River).

Abrupt global warming poses threats to hydrological cycles and peatland ecosystem development. Northern peatlands, such as palsa mires, experience prompt degradation due to disappearing ice cores caused by increasing air temperatures and changes in precipitation patterns that induce the development of thicker snow covers insulating existing ice cores that impair their development. Disappearing palsa mires are experiencing subsidence, which in turn is flattening their topography and changing their hydration. What's more, changes in the shape and position of the ice cores cause local changes in water flow, and the lowering surface of the peatlands approaches the groundwater table, increasing their saturation. Increasing the moisture content of the topsoil within the degrading palsa mire system, in turn, causes changes in biogeochemical processes manifested in changes in water balance, carbon balance, and plant species composition. It, therefore, seems that the ongoing decomposition of palsa mires results in the development of novel peatland ecosystems, which, despite not being affected by the thermokarst processes, are suspected to become effective carbon sinks capable to sequestrate massive amounts of carbon that, in turn, may decrease greenhouse gas emissions.We conducted a comprehensive field-research-based study on Šuoššjávri palsa mire located in Northern Norway (Finnmark). We documented the water balance of the peatland. We described the structure of the palsa mire with the use of electrical resistivity imaging. We modeled the directions of groundwater flow. We applied an Interferometric Satellite Radar approach to quantify the speed of peatland subsidence. We used automated chambers to measure greenhouse gas emissions in a gradient of palsa peatland deterioration and a thermokarst lake. We also applied a novel approach to document vertical profiles of dCO2 and dCH4 content in groundwater at different levels of the peatland with the use of newly developed piezometers to check whether palsa-deterioration-driven groundwater flow patterns can affect carbon sequestration.We documented that subsidence of palsa peatland occurs at a rate of about 2 mm/year while peatlands formed in place of disappearing palsa peatland grow steadily, most likely due to the persistence of stable moisture content and the maintenance of a proper peat-forming process. We revealed that the degradation of palsa mire can be expressed by a range of hydrological indicators representing the duration of groundwater levels at specific depths: inundation time at matured peatlands that remain one of the last steps of palsa mire degradation is shortening, which, in turn, results in limiting methane emissions, yet keeping the carbon dioxide emissions at levels twice as low as the ones documented in a thermokarst lake. Botanical analyses allowed us to describe the development of peatlands that formed in the place of degraded palsa mires and to quantify biomass production and peat accumulation.In the light of results of our study, we hypothesize that degradation of palsa peatlands due to climatic change results in the development of peatland ecosystems that are likely to prevent global warming due to stable and high topsoil saturation followed by an efficient carbon sequestration in the peat-forming process and novel peatland development.

This publication presents data on geophysical measurements performed in the Rospuda wetlands located in North-Eastern Poland. The measurements were carried out by means of the the Electrical Resistivity Imaging (ERI) method, which so far was to our best knowledge never used in the River Rospuda wetland valley. The ERI data were collected in single survey campaign in November 2022 to account for the wet season. During the campaign two ERI profiles were measured. The aim of the field works was to provide the material for illustration of the arrangement of geological layers creating the wetland. The data repository contains detailed data descriptions for each survey site. The ERI data from the selected survey sites can be used first of all to create the conceptual numerical model of groundwater and surface water interaction in this environmentally valuable area, which is to a certain extent a scientific terra incognita, but also for hydrological investigation of hydraulic conductivity and hydrodynamic field, identify geological structure, and characterize engineering properties of the organic soils.