Christian Wille

Water-air fluxes of carbon dioxide (CO₂) and methane (CH₄) in lakes exhibit substantial spatial heterogeneity, often varying across remarkably fine spatial scales. While manual flux chamber measurements offer high spatial resolution and the potential to capture this variability, their application is typically constrained by labor intensity and logistical limitations. In contrast, eddy covariance (EC) measurements integrate fluxes over a larger footprint, effectively averaging over spatial gradients and complicating a process-based interpretation of the data. Bridging this gap requires methods that combine spatial precision with scalable, continuous monitoring – essential for advancing our mechanistic understanding of lake carbon dynamics. To facilitate highly resolved biogeochemical measurements, we developed BlueMinerva, an autonomous platform to monitor surface carbon fluxes with the static chamber method, and simultaneously determine physicochemical, biological, bathymetric, and meteorological variables at pre-defined locations. The platform can be programmed to navigate a user-defined track across a waterbody, and collect flux and ancillary data both in transit and at fixed locations for several hours to days, depending on the sensor configuration and related battery requirements. We deployed the setup at Dagow Lake (Germany) and in a small lake in the Stordalen Mire (Sweden). In total, we obtained 485 chamber-derived flux estimates over 72 measurement hours. We compared CO₂ flux estimates between measurements with two different gas analyzers that were simultaneously mounted on the BlueMinerva. The lower-cost sensor (CARBOCAP GMP343, Vaisala) performed equally well as the precise, but costlier sensor (LI-7810, LI-COR) as long as measurements were sufficiently long (around 5 min). Furthermore, we compared measured carbon fluxes with those from an eddy covariance tower at Dagow Lake where CH₄ fluxes diverged slightly, possibly linked to the usage of different sensors (closed-path versus open-path), while magnitudes of CO₂ fluxes matched well. At both lakes, we identified areas of higher emissions, especially for CH₄, and were thus able to resolve the spatial variability of carbon fluxes within the waterbodies. Concurrently, we measured differences in meteorological conditions, and critical limnological variables (water temperature, specific conductivity, pH, dissolved oxygen, chlorophyll, phycocyanin, turbidity, and fluorescent dissolved organic matter) – valuable measurements that enable a comprehensive assessment of environmental drivers behind flux variability. We conclude that platforms like the BlueMinerva have the potential to be adopted widely by scientists and stakeholders to better capture biogeochemical processes in lakes at high spatial and temporal resolution.

Water-air fluxes of carbon dioxide (CO₂) and methane (CH₄) in lakes exhibit substantial spatial heterogeneity, often varying across remarkably fine spatial scales. While manual flux chamber measurements offer high spatial resolution and the potential to capture this variability, their application is typically constrained by labor intensity and logistical limitations. In contrast, eddy covariance (EC) measurements integrate fluxes over a larger footprint, effectively averaging over spatial gradients and complicating a process-based interpretation of the data. Bridging this gap requires methods that combine spatial precision with scalable, continuous monitoring – essential for advancing our mechanistic understanding of lake carbon dynamics. To facilitate highly resolved biogeochemical measurements, we developed BlueMinerva, an autonomous platform to monitor surface carbon fluxes with the static chamber method, and simultaneously determine physicochemical, biological, bathymetric, and meteorological variables at pre-defined locations. The platform can be programmed to navigate a user-defined track across a waterbody, and collect flux and ancillary data both in transit and at fixed locations for several hours to days, depending on the sensor configuration and related battery requirements. We deployed the setup at Dagow Lake (Germany) and in a small lake in the Stordalen Mire (Sweden). In total, we obtained 485 chamber-derived flux estimates over 72 measurement hours. We compared CO₂ flux estimates between measurements with two different gas analyzers that were simultaneously mounted on the BlueMinerva. The lower-cost sensor (CARBOCAP GMP343, Vaisala) performed equally well as the precise, but costlier sensor (LI-7810, LI-COR) as long as measurements were sufficiently long (around 5 min). Furthermore, we compared measured carbon fluxes with those from an eddy covariance tower at Dagow Lake where CH₄ fluxes diverged slightly, possibly linked to the usage of different sensors (closed-path versus open-path), while magnitudes of CO₂ fluxes matched well. At both lakes, we identified areas of higher emissions, especially for CH₄, and were thus able to resolve the spatial variability of carbon fluxes within the waterbodies. Concurrently, we measured differences in meteorological conditions, and critical limnological variables (water temperature, specific conductivity, pH, dissolved oxygen, chlorophyll, phycocyanin, turbidity, and fluorescent dissolved organic matter) – valuable measurements that enable a comprehensive assessment of environmental drivers behind flux variability. We conclude that platforms like the BlueMinerva have the potential to be adopted widely by scientists and stakeholders to better capture biogeochemical processes in lakes at high spatial and temporal resolution.

Measurements of surface-atmosphere carbon dioxide (CO ₂ ) and methane (CH ₄ ) fluxes have been relatively sparse across the Arctic tundra and boreal biomes, causing significant uncertainties in carbon budget estimates from the region. While the availability of Arctic-boreal carbon flux data has increased substantially over the past decade, the data have remained spread across different repositories, scientific articles, and unpublished sources, making it difficult to leverage. Here we present a new dataset of monthly Arctic-boreal carbon fluxes (ABCFlux v2) across terrestrial (wetlands and uplands) and freshwater (lakes and rivers) ecosystems compiled from previous syntheses including the Arctic-boreal CO ₂ flux database (ABCFlux v1), the Boreal-Arctic Wetland and Lake Methane Dataset (BAWLD-CH4), and the Global River Methane Database (GRiMeDB). In addition, we consider data from general-purpose (e.g., Zenodo) and flux network repositories, literature, and site principal investigators. The dataset includes surface-atmosphere CO ₂ fluxes of gross primary production (GPP), ecosystem respiration (Reco), and net ecosystem exchange (NEE), alongside CH ₄ fluxes. For aquatic ecosystems, we split CH ₄ fluxes into diffusive and ebullitive flux pathways, and included potential emissions from transient storage in the water column (“storage fluxes”), alongside CO ₂ and CH ₄ concentrations dissolved in the surface water. Fluxes are measured through a variety of methods including chamber and eddy covariance techniques alongside bubble traps, ice-surveys, and concentration-based turbulence-driven modelling in aquatic ecosystems. The monthly flux data are reported together with supporting methodological and environmental metadata. The resulting ABCFlux v2 has 23 847 flux site-months, 8182 concentration site-months, and 199 seasonal observations from 1024 sites, and includes 56 139 reported fluxes (i.e. sum of GPP, Reco, NEE, and CH ₄ fluxes) from the years 1984 to 2024. The majority of monthly observations occurred after 1999. Wetlands had the highest number of site-month observations (8758), followed by boreal forest (6981), lotic ecosystems (6275), lentic ecosystems (3799) and upland tundra (3308). Measurements of CO ₂ dominated the dataset across most ecosystem types (25 222) except for lentic ecosystems, where CH ₄ flux site-months (3098) were more frequent than CO ₂ flux site-months (2915). Overall, ABCFlux v2 includes 160 % more site-months for terrestrial CO ₂ flux data compared to ABCFlux v1. Integrating and updating BAWLD-CH4 flux data from growing season averages to monthly fluxes resulted in 5671 site-months of chamber CH ₄ data compared to 762 site-years. This collaborative initiative, involving contributions from over 260 researchers, provides a comprehensive overview of the current state of the Arctic-boreal carbon flux network and its data, and serves as an important step in reducing uncertainties in Arctic-boreal carbon budgets and in enhancing our understanding of climate feedbacks. The data can be accessed at ORNL DAAC at https://doi.org/10.3334/ORNLDAAC/2448 (Virkkala et al., 2026).

Water-air fluxes of carbon dioxide (CO₂) and methane (CH₄) in lakes exhibit substantial spatial heterogeneity, often varying across remarkably fine spatial scales. While manual flux chamber measurements offer high spatial resolution and the potential to capture this variability, their application is typically constrained by labor intensity and logistical limitations. In contrast, eddy covariance (EC) measurements integrate fluxes over a larger footprint, effectively averaging over spatial gradients and complicating a process-based interpretation of the data. Bridging this gap requires methods that combine spatial precision with scalable, continuous monitoring – essential for advancing our mechanistic understanding of lake carbon dynamics. To facilitate highly resolved biogeochemical measurements, we developed BlueMinerva, an autonomous platform to monitor surface carbon fluxes with the static chamber method, and simultaneously determine physicochemical, biological, bathymetric, and meteorological variables at pre-defined locations. The platform can be programmed to navigate a user-defined track across a waterbody, and collect flux and ancillary data both in transit and at fixed locations for several hours to days, depending on the sensor configuration and related battery requirements. We deployed the setup at Dagow Lake (Germany) and in a small lake in the Stordalen Mire (Sweden). In total, we obtained 485 chamber-derived flux estimates over 72 measurement hours. We compared CO₂ flux estimates between measurements with two different gas analyzers that were simultaneously mounted on the BlueMinerva. The lower-cost sensor (CARBOCAP GMP343, Vaisala) performed equally well as the precise, but costlier sensor (LI-7810, LI-COR) as long as measurements were sufficiently long (around 5 min). Furthermore, we compared measured carbon fluxes with those from an eddy covariance tower at Dagow Lake where CH₄ fluxes diverged slightly, possibly linked to the usage of different sensors (closed-path versus open-path), while magnitudes of CO₂ fluxes matched well. At both lakes, we identified areas of higher emissions, especially for CH₄, and were thus able to resolve the spatial variability of carbon fluxes within the waterbodies. Concurrently, we measured differences in meteorological conditions, and critical limnological variables (water temperature, specific conductivity, pH, dissolved oxygen, chlorophyll, phycocyanin, turbidity, and fluorescent dissolved organic matter) – valuable measurements that enable a comprehensive assessment of environmental drivers behind flux variability. We conclude that platforms like the BlueMinerva have the potential to be adopted widely by scientists and stakeholders to better capture biogeochemical processes in lakes at high spatial and temporal resolution.

Water-air fluxes of carbon dioxide (CO₂) and methane (CH₄) in lakes exhibit substantial spatial heterogeneity, often varying across remarkably fine spatial scales. While manual flux chamber measurements offer high spatial resolution and the potential to capture this variability, their application is typically constrained by labor intensity and logistical limitations. In contrast, eddy covariance (EC) measurements integrate fluxes over a larger footprint, effectively averaging over spatial gradients and complicating a process-based interpretation of the data. Bridging this gap requires methods that combine spatial precision with scalable, continuous monitoring – essential for advancing our mechanistic understanding of lake carbon dynamics. To facilitate highly resolved biogeochemical measurements, we developed BlueMinerva, an autonomous platform to monitor surface carbon fluxes with the static chamber method, and simultaneously determine physicochemical, biological, bathymetric, and meteorological variables at pre-defined locations. The platform can be programmed to navigate a user-defined track across a waterbody, and collect flux and ancillary data both in transit and at fixed locations for several hours to days, depending on the sensor configuration and related battery requirements. We deployed the setup at Dagow Lake (Germany) and in a small lake in the Stordalen Mire (Sweden). In total, we obtained 485 chamber-derived flux estimates over 72 measurement hours. We compared CO₂ flux estimates between measurements with two different gas analyzers that were simultaneously mounted on the BlueMinerva. The lower-cost sensor (CARBOCAP GMP343, Vaisala) performed equally well as the precise, but costlier sensor (LI-7810, LI-COR) as long as measurements were sufficiently long (around 5 min). Furthermore, we compared measured carbon fluxes with those from an eddy covariance tower at Dagow Lake where CH₄ fluxes diverged slightly, possibly linked to the usage of different sensors (closed-path versus open-path), while magnitudes of CO₂ fluxes matched well. At both lakes, we identified areas of higher emissions, especially for CH₄, and were thus able to resolve the spatial variability of carbon fluxes within the waterbodies. Concurrently, we measured differences in meteorological conditions, and critical limnological variables (water temperature, specific conductivity, pH, dissolved oxygen, chlorophyll, phycocyanin, turbidity, and fluorescent dissolved organic matter) – valuable measurements that enable a comprehensive assessment of environmental drivers behind flux variability. We conclude that platforms like the BlueMinerva have the potential to be adopted widely by scientists and stakeholders to better capture biogeochemical processes in lakes at high spatial and temporal resolution.

Water-air fluxes of carbon dioxide (CO₂) and methane (CH₄) in lakes exhibit substantial spatial heterogeneity, often varying across remarkably fine spatial scales. While manual flux chamber measurements offer high spatial resolution and the potential to capture this variability, their application is typically constrained by labor intensity and logistical limitations. In contrast, eddy covariance (EC) measurements integrate fluxes over a larger footprint, effectively averaging over spatial gradients and complicating a process-based interpretation of the data. Bridging this gap requires methods that combine spatial precision with scalable, continuous monitoring – essential for advancing our mechanistic understanding of lake carbon dynamics. To facilitate highly resolved biogeochemical measurements, we developed BlueMinerva, an autonomous platform to monitor surface carbon fluxes with the static chamber method, and simultaneously determine physicochemical, biological, bathymetric, and meteorological variables at pre-defined locations. The platform can be programmed to navigate a user-defined track across a waterbody, and collect flux and ancillary data both in transit and at fixed locations for several hours to days, depending on the sensor configuration and related battery requirements. We deployed the setup at Dagow Lake (Germany) and in a small lake in the Stordalen Mire (Sweden). In total, we obtained 485 chamber-derived flux estimates over 72 measurement hours. We compared CO₂ flux estimates between measurements with two different gas analyzers that were simultaneously mounted on the BlueMinerva. The lower-cost sensor (CARBOCAP GMP343, Vaisala) performed equally well as the precise, but costlier sensor (LI-7810, LI-COR) as long as measurements were sufficiently long (around 5 min). Furthermore, we compared measured carbon fluxes with those from an eddy covariance tower at Dagow Lake where CH₄ fluxes diverged slightly, possibly linked to the usage of different sensors (closed-path versus open-path), while magnitudes of CO₂ fluxes matched well. At both lakes, we identified areas of higher emissions, especially for CH₄, and were thus able to resolve the spatial variability of carbon fluxes within the waterbodies. Concurrently, we measured differences in meteorological conditions, and critical limnological variables (water temperature, specific conductivity, pH, dissolved oxygen, chlorophyll, phycocyanin, turbidity, and fluorescent dissolved organic matter) – valuable measurements that enable a comprehensive assessment of environmental drivers behind flux variability. We conclude that platforms like the BlueMinerva have the potential to be adopted widely by scientists and stakeholders to better capture biogeochemical processes in lakes at high spatial and temporal resolution.

The Tibetan Plateau (TP) is warming rapidly, with future projections suggesting continued warming that may amplify climate–carbon feedbacks. However, sparse in-situ observations and pronounced spatial heterogeneity in vegetation, soil moisture, and climate have limited our understanding of these ecosystem responses. Here, we present a continuous record of carbon and energy fluxes measured at a landscape scale (∼30 ha (0.3 km ² )) in an alpine steppe ecosystem on the TP from July 2018 to June 2019. The dataset yields a cumulative net ecosystem exchange (NEE) of -12.6±16.4 g C m ⁻² , indicating a near carbon-neutral budget. Flux measurements were quality-filtered, retaining 33 %–44 % of high-quality data across fluxes, and gap-filled to produce a complete seasonal record using two complementary approaches, marginal distribution sampling (MDS) and random forest (RF), with RF outperforming MDS for all the fluxes. Eddy covariance measurements represent integrated fluxes over their footprint area, which are often much smaller than most model grids or remote sensing pixels, particularly in grassland ecosystems. Owing to the higher measurement height (19 m) at this site, the footprint climatology (90 % source area ≈ 280 000 m ² ) closely aligns with the spatial coverage of a Moderate Resolution Imaging Spectroradiometer (MODIS) 500 m pixel (∼250 000 m ² ), making this dataset particularly suitable for future landscape-scale comparisons and satellite product validation. The data include quality flags indicating observed or gap-filled values, uncertainty estimates, footprint diagnostics, and auxiliary meteorological variables (air and soil temperature, soil moisture, radiation, relative humidity, vapour pressure deficit). The data described in this manuscript provides a robust foundation for examining carbon–climate interactions in alpine environments and supporting ecosystem modeling (https://doi.org/10.5880/GFZ.TKVR.2026.001, Pillai et al., 2026).

The Tibetan Plateau (TP) is warming rapidly, with future projections suggesting continued warming that may amplify climate–carbon feedbacks. However, sparse in-situ observations and pronounced spatial heterogeneity in vegetation, soil moisture, and climate have limited our understanding of these ecosystem responses. Here, we present a continuous record of carbon and energy fluxes measured at a landscape scale (~30 ha / 0.3 km²) in an alpine steppe ecosystem on the TP from July 2018 to June 2019. Flux measurements were quality-filtered and gap-filled to produce a complete seasonal record using two complementary approaches, marginal distribution sampling (MDS) and random forest (RF). Eddy covariance measurements represent integrated fluxes over their footprint area, which are often much smaller than most model grids or remote sensing pixels, particularly in grassland ecosystems. Owing to the higher measurement height (19 m) at this site, the measurement footprint closely aligns with the spatial resolution of Moderate Resolution Imaging Spectroradiometer (MODIS) products, facilitating more consistent landscape-scale comparisons. The data include quality flags indicating observed or gap-filled values, uncertainty estimates, footprint diagnostics, and auxiliary meteorological variables. The data described in this manuscript provides a robust foundation for examining carbon–climate interactions in alpine environments, supporting ecosystem modeling and satellite product validation.

Water-air fluxes of carbon dioxide (CO2) and methane (CH4) in lakes exhibit substantial spatial heterogeneity, often varying across remarkably fine spatial scales. While manual flux chamber measurements offer high spatial resolution and the potential to capture this variability, their application is typically constrained by labor intensity and logistical limitations. In contrast, eddy covariance (EC) measurements integrate fluxes over a larger footprint, effectively averaging over spatial gradients and complicating a process-based interpretation of the data. Bridging this gap requires methods that combine spatial precision with scalable, continuous monitoring – essential for advancing our mechanistic understanding of lake carbon dynamics. To facilitate highly resolved biogeochemical measurements, we developed BlueMinerva, an autonomous platform to monitor surface carbon fluxes with the static chamber method, and simultaneously determine physicochemical, biological, bathymetric, and meteorological variables at pre-defined locations. The platform can be programmed to navigate a user-defined track across a waterbody, and collect flux and ancillary data both in transit and at fixed locations for several hours to days, depending on the sensor configuration and related battery requirements. We deployed the setup at Dagow Lake (Germany) and in a small lake in the Stordalen Mire (Sweden). In total, we obtained 485 chamber-derived flux estimates over 72 measurement hours. We compared CO2 flux estimates between measurements with two different gas analyzers that were simultaneously mounted on the BlueMinerva. The lower-cost sensor (CARBOCAP GMP343, Vaisala) performed equally well as the precise, but costlier sensor (LI-7810, LI-COR) as long as measurements were sufficiently long (around 5 min). Furthermore, we compared measured carbon fluxes with those from an eddy covariance tower at Dagow Lake where CH4 fluxes diverged slightly, possibly linked to the usage of different sensors (closed-path versus open-path), while magnitudes of CO2 fluxes matched well. At both lakes, we identified areas of higher emissions, especially for CH4, and were thus able to resolve the spatial variability of carbon fluxes within the waterbodies. Concurrently, we measured differences in meteorological conditions, and critical limnological variables (water temperature, specific conductivity, pH, dissolved oxygen, chlorophyll, phycocyanin, turbidity, and fluorescent dissolved organic matter) – valuable measurements that enable a comprehensive assessment of environmental drivers behind flux variability. We conclude that platforms like the BlueMinerva have the potential to be adopted widely by scientists and stakeholders to better capture biogeochemical processes in lakes at high spatial and temporal resolution.

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.