Inge Althuizen | University of Bergen (original) (raw)

Papers by Inge Althuizen

Research paper thumbnail of Volatile organic compound release across a permafrost-affected peatland

Research paper thumbnail of Supplementary material to "Explicitly modelling microtopography in permafrost landscapes in a land-surface model (JULES vn5.4_microtopography)&quot

Research paper thumbnail of Long lasting greenhouse gas emissions beyond abrupt permafrost thaw event in permafrost peatlands

<p>Abrupt permafrost thawing is expected to release large amounts o... more <p>Abrupt permafrost thawing is expected to release large amounts of greenhouse gasses to the atmosphere, creating a positive feedback to climate warming. There is, however, still large uncertainty in the timing, duration, magnitude, and mechanisms controlling this process, which hampers accurate quantification of permafrost carbon climate feedback cycles. The current understanding supports that abrupt permafrost thaw will lead to surface inundation and create anaerobic landscapes, which dominantly produce methane during the decomposition process. Over time, natural succession and vegetation growth may decrease methane release and increase net carbon uptake. We investigated how rapid permafrost thawing and subsequent natural succession over time affect CO<sub>2</sub>, CH<sub>4</sub>, and N<sub>2</sub>O release at a field site in northern Norway (69ᵒN), where recent abrupt degradation of permafrost created thaw ponds in palsa peat plateau-mire ecosystems. The site exhibits a natural gradient of permafrost thaw, which also corresponds to a strong hydrological gradient (i.e. dry peat plateau underlain by intact permafrost, seasonally inundated thaw slumps, thaw ponds, and natural succession ponds covered by sphagnum and sedges). Since 2017, we used a range of manual and automated techniques to measure changes in vegetation, soil and water microclimate, biogeochemistry, and soil CO<sub>2</sub>, CH<sub>4</sub>, and N<sub>2</sub>O concentrations and fluxes across the permafrost thaw gradient. In the three-year observations, we show that abrupt permafrost thaw and land surface subsidence – both intermediate slumping and pond formation – increase net annual carbon loss. Permafrost thaw accelerated CO<sub>2</sub> release greatly in thaw slumps (177.5 gCO<sub>2</sub> m<sup>-2</sup>) compared to intact permafrost peat plateau (59.0 gCO<sub>2</sub> m<sup>-2</sup>). During the growing season, peat plateau was a small sink of atmospheric CH<sub>4</sub> (-2.5 gCH<sub>4</sub> m<sup>-2</sup>), whereas permafrost thaw slumping and pond formation increased CH<sub>4</sub> release dramatically (ranging from 9.7 to 36.1 gCH<sub>4</sub> m<sup>-2</sup>). Furthermore, CH<sub>4</sub> release continues to increase even in natural succession pond likely due to aerenchyma transport of CH<sub>4</sub> from deeper soil. The overall N<sub>2</sub>O release was negligeable except in the bare soil peat plateau. The net radiative forcing of ecosystem carbon balance will depend on the carbon uptake from the natural succession of vegetation, but we show that greenhouse gas emissions continue to increase beyond abrupt permafrost thaw event towards natural succession.</p>

Research paper thumbnail of Volatile carbon emissions from a degrading permafrost peatland

<p>Permafrost in the north Polar Regions stores more than 1,500 Pg of organ... more <p>Permafrost in the north Polar Regions stores more than 1,500 Pg of organic carbon, which is nearly twice as much as the atmospheric carbon pool. As the Arctic region is experiencing unprecedented warming, accelerated decomposition in permafrost is potentially switching it to a hotspot of carbon emissions. In addition to the widely studies carbon dioxide and methane, permafrost may also be a source of biogenic volatile organic compounds (BVOCs), a reactive group of trace gases which have so far received much less attention. BVOCs can prolong the lifetime of methane through the depletion of hydroxyl radicals, contribute to ozone formation, and lead to the formation of secondary organic aerosol, and thus exert significant impact on climate forcing, especially in unpolluted Arctic region.</p><p>Here, we conducted in situ measurements of soil BVOC emissions on an actively degrading permafrost peatland during a growing season. We compared emissions along a gradient of landscape units from soil palsa and vegetated palsa to thaw slump, thaw pond and vegetated thaw pond. BVOC samples were collected onto absorbent cartridges using dynamic enclosure chamber method, and then analyzed with a gas chromatograph coupled with a mass spectrometer (GC/MS), based upon which the emission rates were calculated.</p><p>Results suggested that all landscapes units across the peatland showed net emissions of BVOCs during the summertime. Major BVOC groups included monoterpenes, sesquiterpenes, isoprene, hydrocarbons, methanol, acetone, other oxygenated VOCs and other compounds, and these groups were present in all landscape units. All VOC groups also exhibited seasonal and spatial variations across the different sampling months and landscape units. For example, the actively degrading thaw slump showed higher monoterpene emissions that other landscape units, while sesquiterpene emissions were highest from the vegetated thaw ponds. Principal component analysis further revealed temporal and spatial patterns in the relative compositions of the BVOC profiles. Our results show that soil BVOC emissions change in response to active permafrost thaw.</p>

Research paper thumbnail of Standardized monitoring of permafrost thaw: a user-friendly, multiparameter protocol (T-MOSAiC)

Climate change is destabilizing permafrost landscapes, affecting infrastructure, ecosystems, and ... more Climate change is destabilizing permafrost landscapes, affecting infrastructure, ecosystems, and human livelihoods. The rate of permafrost thaw is controlled by surface and subsurface properties and processes, all of which are potentially linked with each other. However, no standardized protocol exists for measuring permafrost thaw and related processes and properties in a linked manner. The permafrost thaw action group of the Terrestrial Multidisciplinary distributed Observatories for the Study of the Arctic Connections (T-MOSAiC) project has developed a protocol, for use by non-specialist scientists and technicians, citizen scientists, and indigenous groups, to collect standardized metadata and data on permafrost thaw. The protocol introduced here addresses the need to jointly measure permafrost thaw and the associated surface and subsurface environmental conditions. The parameters measured along transects include: snow depth, thaw depth, vegetation height, soil texture, and water level. The metadata collection includes data on timing of data collection, geographical coordinates, land surface characteristics (vegetation, ground surface, water conditions), as well as photographs. Our hope is that this openly

Research paper thumbnail of Intraspecific trait variability is a key feature underlying high Arctic plant community resistance to climate warming

Ecological Monographs, Dec 9, 2022

Research paper thumbnail of The role of plant functional groups mediating climate impacts on carbon and biodiversity of alpine grasslands

Scientific Data, Jul 28, 2022

Plant removal experiments allow assessment of the role of biotic interactions among species or fu... more Plant removal experiments allow assessment of the role of biotic interactions among species or functional groups in community assembly and ecosystem functioning. When replicated along climate gradients, they can assess changes in interactions among species or functional groups with climate. Across twelve sites in the Vestland Climate Grid (VCG) spanning 4 °C in growing season temperature and 2000 mm in mean annual precipitation across boreal and alpine regions of Western Norway, we conducted a fully factorial plant functional group removal experiment (graminoids, forbs, bryophytes). Over six years, we recorded biomass removed, soil microclimate, plant community composition and structure, seedling recruitment, ecosystem carbon fluxes, and reflectance in 384 experimental and control plots. The dataset consists of 5,412 biomass records, 360 species-level biomass records, 1,084,970 soil temperature records, 4,771 soil moisture records, 17,181 plant records covering 206 taxa, 16,656 seedling records, 3,696 ecosystem carbon flux measurements, and 1,244 reflectance measurements. The data can be combined with longer-term climate data and plant population, community, ecosystem, and functional trait data collected within the VCG.

Research paper thumbnail of Explicitly modelling microtopography in permafrost landscapes in a land surface model (JULES vn5.4_microtopography)

Geoscientific Model Development, May 6, 2022

Research paper thumbnail of Climate–ecosystem modelling made easy: The Land Sites Platform

Global Change Biology

Dynamic Global Vegetation Models (DGVMs) provide a state‐of‐the‐art process‐based approach to stu... more Dynamic Global Vegetation Models (DGVMs) provide a state‐of‐the‐art process‐based approach to study the complex interplay between vegetation and its physical environment. For example, they help to predict how terrestrial plants interact with climate, soils, disturbance and competition for resources. We argue that there is untapped potential for the use of DGVMs in ecological and ecophysiological research. One fundamental barrier to realize this potential is that many researchers with relevant expertize (ecology, plant physiology, soil science, etc.) lack access to the technical resources or awareness of the research potential of DGVMs. Here we present the Land Sites Platform (LSP): new software that facilitates single‐site simulations with the Functionally Assembled Terrestrial Ecosystem Simulator, an advanced DGVM coupled with the Community Land Model. The LSP includes a Graphical User Interface and an Application Programming Interface, which improve the user experience and lower t...

Research paper thumbnail of Disaggregating the carbon exchange of degrading permafrost peatlands using Bayesian deep learning

Extensive regions in the permafrost zone are projected to become climatically unsuitable to susta... more Extensive regions in the permafrost zone are projected to become climatically unsuitable to sustain permafrost peatlands over the next century, suggesting transformations in these landscapes that can leave large amounts of permafrost carbon vulnerable to post-thaw decomposition. We present three years of eddy covariance measurements of CH4 and CO2 fluxes from the degrading permafrost peatland Iskoras in Northern Norway, which we disaggregate into separate fluxes of palsa, pond, and fen areas using information provided by the dynamic flux footprint in a novel ensemble-based Bayesian deep neural network framework. The three-year mean CO2-equivalent flux is estimated to be 106 gCO2 m-2 yr-1 for palsas, 1780 gCO2 m-2 yr-1 for ponds, and -31 gCO2 m-2 yr-1 for fens, indicating that possible palsa degradation to thermokarst ponds would strengthen the local greenhouse gas forcing by a factor of about 17, while transformation into fens would slightly reduce the current local greenhouse gas f...

Research paper thumbnail of Bryophytes dominate plant regulation of soil microclimate in alpine grasslands

Oikos

Soil temperature and moisture are important regulators of a broad range of biotic and abiotic pro... more Soil temperature and moisture are important regulators of a broad range of biotic and abiotic processes in terrestrial ecosystems. Vegetation can, in turn, play a role in regulating soil microclimate, which creates potential for powerful and interactive feedbacks from soil and vegetation on the atmosphere. Although the regulatory effect of vegetation on soil microclimatic conditions has been quite extensively and empirically assessed, most studies have determined the net effect of intact woody vegetation versus bare ground. However, for other plant functional groups we lack a clear understanding of their role and any climate‐context dependency in controlling microclimatic conditions.We investigated the role of three major plant functional groups – graminoids, forbs and bryophytes – in regulating soil microclimate in semi‐natural alpine grasslands. Using a fully factorial above‐ground biomass removal experiment, we assessed the role of these plant functional groups in regulating soil...

Research paper thumbnail of Volatile organic compound release across a permafrost-affected peatland

Research paper thumbnail of The role of plant functional groups mediating climate impacts on carbon and biodiversity of alpine grasslands

Scientific Data

Plant removal experiments allow assessment of the role of biotic interactions among species or fu... more Plant removal experiments allow assessment of the role of biotic interactions among species or functional groups in community assembly and ecosystem functioning. When replicated along climate gradients, they can assess changes in interactions among species or functional groups with climate. Across twelve sites in the Vestland Climate Grid (VCG) spanning 4 °C in growing season temperature and 2000 mm in mean annual precipitation across boreal and alpine regions of Western Norway, we conducted a fully factorial plant functional group removal experiment (graminoids, forbs, bryophytes). Over six years, we recorded biomass removed, soil microclimate, plant community composition and structure, seedling recruitment, ecosystem carbon fluxes, and reflectance in 384 experimental and control plots. The dataset consists of 5,412 biomass records, 360 species-level biomass records, 1,084,970 soil temperature records, 4,771 soil moisture records, 17,181 plant records covering 206 taxa, 16,656 seed...

Research paper thumbnail of Multiscale mapping of plant functional groups and plant traits in the High Arctic using field spectroscopy, UAV imagery and Sentinel-2A data

Environmental Research Letters, 2021

The Arctic is warming twice as fast as the rest of the planet, leading to rapid changes in specie... more The Arctic is warming twice as fast as the rest of the planet, leading to rapid changes in species composition and plant functional trait variation. Landscape-level maps of vegetation composition and trait distributions are required to expand spatially-limited plot studies, overcome sampling biases associated with the most accessible research areas, and create baselines from which to monitor environmental change. Unmanned aerial vehicles (UAVs) have emerged as a low-cost method to generate high-resolution imagery and bridge the gap between fine-scale field studies and lower resolution satellite analyses. Here we used field spectroscopy data (400–2500 nm) and UAV multispectral imagery to test spectral methods of species identification and plant water and chemistry retrieval near Longyearbyen, Svalbard. Using the field spectroscopy data and Random Forest analysis, we were able to distinguish eight common High Arctic plant tundra species with 74% accuracy. Using partial least squares r...

Research paper thumbnail of Intraspecific trait variability is a key feature underlying high Arctic plant community resistance to climate warming

Research paper thumbnail of Standardized monitoring of permafrost thaw: a user-friendly, multiparameter protocol (T-MOSAiC)

EPIC3Svalbard Science Conference 2021, 2021-11-02-2021-11-03, Nov 3, 2021

Research paper thumbnail of Supplementary material to "Explicitly modelling microtopography in permafrost landscapes in a land-surface model (JULES vn5.4_microtopography)

Research paper thumbnail of Trait Shifts affect Ecosystem Carbon Exchange under Climate Change in Alpine Grasslands

AGU Fall Meeting Abstracts, Dec 1, 2018

Research paper thumbnail of Volatile carbon emissions from a degrading permafrost peatland

<p>Permafrost in the north Polar Regions stores more than 1,500 Pg of organ... more <p>Permafrost in the north Polar Regions stores more than 1,500 Pg of organic carbon, which is nearly twice as much as the atmospheric carbon pool. As the Arctic region is experiencing unprecedented warming, accelerated decomposition in permafrost is potentially switching it to a hotspot of carbon emissions. In addition to the widely studies carbon dioxide and methane, permafrost may also be a source of biogenic volatile organic compounds (BVOCs), a reactive group of trace gases which have so far received much less attention. BVOCs can prolong the lifetime of methane through the depletion of hydroxyl radicals, contribute to ozone formation, and lead to the formation of secondary organic aerosol, and thus exert significant impact on climate forcing, especially in unpolluted Arctic region.</p><p>Here, we conducted in situ measurements of soil BVOC emissions on an actively degrading permafrost peatland during a growing season. We compared emissions along a gradient of landscape units from soil palsa and vegetated palsa to thaw slump, thaw pond and vegetated thaw pond. BVOC samples were collected onto absorbent cartridges using dynamic enclosure chamber method, and then analyzed with a gas chromatograph coupled with a mass spectrometer (GC/MS), based upon which the emission rates were calculated.</p><p>Results suggested that all landscapes units across the peatland showed net emissions of BVOCs during the summertime. Major BVOC groups included monoterpenes, sesquiterpenes, isoprene, hydrocarbons, methanol, acetone, other oxygenated VOCs and other compounds, and these groups were present in all landscape units. All VOC groups also exhibited seasonal and spatial variations across the different sampling months and landscape units. For example, the actively degrading thaw slump showed higher monoterpene emissions that other landscape units, while sesquiterpene emissions were highest from the vegetated thaw ponds. Principal component analysis further revealed temporal and spatial patterns in the relative compositions of the BVOC profiles. Our results show that soil BVOC emissions change in response to active permafrost thaw.</p>

Research paper thumbnail of Long lasting greenhouse gas emissions beyond abrupt permafrost thaw event in permafrost peatlands

<p>Abrupt permafrost thawing is expected to release large amounts o... more <p>Abrupt permafrost thawing is expected to release large amounts of greenhouse gasses to the atmosphere, creating a positive feedback to climate warming. There is, however, still large uncertainty in the timing, duration, magnitude, and mechanisms controlling this process, which hampers accurate quantification of permafrost carbon climate feedback cycles. The current understanding supports that abrupt permafrost thaw will lead to surface inundation and create anaerobic landscapes, which dominantly produce methane during the decomposition process. Over time, natural succession and vegetation growth may decrease methane release and increase net carbon uptake. We investigated how rapid permafrost thawing and subsequent natural succession over time affect CO<sub>2</sub>, CH<sub>4</sub>, and N<sub>2</sub>O release at a field site in northern Norway (69ᵒN), where recent abrupt degradation of permafrost created thaw ponds in palsa peat plateau-mire ecosystems. The site exhibits a natural gradient of permafrost thaw, which also corresponds to a strong hydrological gradient (i.e. dry peat plateau underlain by intact permafrost, seasonally inundated thaw slumps, thaw ponds, and natural succession ponds covered by sphagnum and sedges). Since 2017, we used a range of manual and automated techniques to measure changes in vegetation, soil and water microclimate, biogeochemistry, and soil CO<sub>2</sub>, CH<sub>4</sub>, and N<sub>2</sub>O concentrations and fluxes across the permafrost thaw gradient. In the three-year observations, we show that abrupt permafrost thaw and land surface subsidence – both intermediate slumping and pond formation – increase net annual carbon loss. Permafrost thaw accelerated CO<sub>2</sub> release greatly in thaw slumps (177.5 gCO<sub>2</sub> m<sup>-2</sup>) compared to intact permafrost peat plateau (59.0 gCO<sub>2</sub> m<sup>-2</sup>). During the growing season, peat plateau was a small sink of atmospheric CH<sub>4</sub> (-2.5 gCH<sub>4</sub> m<sup>-2</sup>), whereas permafrost thaw slumping and pond formation increased CH<sub>4</sub> release dramatically (ranging from 9.7 to 36.1 gCH<sub>4</sub> m<sup>-2</sup>). Furthermore, CH<sub>4</sub> release continues to increase even in natural succession pond likely due to aerenchyma transport of CH<sub>4</sub> from deeper soil. The overall N<sub>2</sub>O release was negligeable except in the bare soil peat plateau. The net radiative forcing of ecosystem carbon balance will depend on the carbon uptake from the natural succession of vegetation, but we show that greenhouse gas emissions continue to increase beyond abrupt permafrost thaw event towards natural succession.</p>

Research paper thumbnail of Volatile organic compound release across a permafrost-affected peatland

Research paper thumbnail of Supplementary material to "Explicitly modelling microtopography in permafrost landscapes in a land-surface model (JULES vn5.4_microtopography)&quot

Research paper thumbnail of Long lasting greenhouse gas emissions beyond abrupt permafrost thaw event in permafrost peatlands

<p>Abrupt permafrost thawing is expected to release large amounts o... more <p>Abrupt permafrost thawing is expected to release large amounts of greenhouse gasses to the atmosphere, creating a positive feedback to climate warming. There is, however, still large uncertainty in the timing, duration, magnitude, and mechanisms controlling this process, which hampers accurate quantification of permafrost carbon climate feedback cycles. The current understanding supports that abrupt permafrost thaw will lead to surface inundation and create anaerobic landscapes, which dominantly produce methane during the decomposition process. Over time, natural succession and vegetation growth may decrease methane release and increase net carbon uptake. We investigated how rapid permafrost thawing and subsequent natural succession over time affect CO<sub>2</sub>, CH<sub>4</sub>, and N<sub>2</sub>O release at a field site in northern Norway (69ᵒN), where recent abrupt degradation of permafrost created thaw ponds in palsa peat plateau-mire ecosystems. The site exhibits a natural gradient of permafrost thaw, which also corresponds to a strong hydrological gradient (i.e. dry peat plateau underlain by intact permafrost, seasonally inundated thaw slumps, thaw ponds, and natural succession ponds covered by sphagnum and sedges). Since 2017, we used a range of manual and automated techniques to measure changes in vegetation, soil and water microclimate, biogeochemistry, and soil CO<sub>2</sub>, CH<sub>4</sub>, and N<sub>2</sub>O concentrations and fluxes across the permafrost thaw gradient. In the three-year observations, we show that abrupt permafrost thaw and land surface subsidence – both intermediate slumping and pond formation – increase net annual carbon loss. Permafrost thaw accelerated CO<sub>2</sub> release greatly in thaw slumps (177.5 gCO<sub>2</sub> m<sup>-2</sup>) compared to intact permafrost peat plateau (59.0 gCO<sub>2</sub> m<sup>-2</sup>). During the growing season, peat plateau was a small sink of atmospheric CH<sub>4</sub> (-2.5 gCH<sub>4</sub> m<sup>-2</sup>), whereas permafrost thaw slumping and pond formation increased CH<sub>4</sub> release dramatically (ranging from 9.7 to 36.1 gCH<sub>4</sub> m<sup>-2</sup>). Furthermore, CH<sub>4</sub> release continues to increase even in natural succession pond likely due to aerenchyma transport of CH<sub>4</sub> from deeper soil. The overall N<sub>2</sub>O release was negligeable except in the bare soil peat plateau. The net radiative forcing of ecosystem carbon balance will depend on the carbon uptake from the natural succession of vegetation, but we show that greenhouse gas emissions continue to increase beyond abrupt permafrost thaw event towards natural succession.</p>

Research paper thumbnail of Volatile carbon emissions from a degrading permafrost peatland

<p>Permafrost in the north Polar Regions stores more than 1,500 Pg of organ... more <p>Permafrost in the north Polar Regions stores more than 1,500 Pg of organic carbon, which is nearly twice as much as the atmospheric carbon pool. As the Arctic region is experiencing unprecedented warming, accelerated decomposition in permafrost is potentially switching it to a hotspot of carbon emissions. In addition to the widely studies carbon dioxide and methane, permafrost may also be a source of biogenic volatile organic compounds (BVOCs), a reactive group of trace gases which have so far received much less attention. BVOCs can prolong the lifetime of methane through the depletion of hydroxyl radicals, contribute to ozone formation, and lead to the formation of secondary organic aerosol, and thus exert significant impact on climate forcing, especially in unpolluted Arctic region.</p><p>Here, we conducted in situ measurements of soil BVOC emissions on an actively degrading permafrost peatland during a growing season. We compared emissions along a gradient of landscape units from soil palsa and vegetated palsa to thaw slump, thaw pond and vegetated thaw pond. BVOC samples were collected onto absorbent cartridges using dynamic enclosure chamber method, and then analyzed with a gas chromatograph coupled with a mass spectrometer (GC/MS), based upon which the emission rates were calculated.</p><p>Results suggested that all landscapes units across the peatland showed net emissions of BVOCs during the summertime. Major BVOC groups included monoterpenes, sesquiterpenes, isoprene, hydrocarbons, methanol, acetone, other oxygenated VOCs and other compounds, and these groups were present in all landscape units. All VOC groups also exhibited seasonal and spatial variations across the different sampling months and landscape units. For example, the actively degrading thaw slump showed higher monoterpene emissions that other landscape units, while sesquiterpene emissions were highest from the vegetated thaw ponds. Principal component analysis further revealed temporal and spatial patterns in the relative compositions of the BVOC profiles. Our results show that soil BVOC emissions change in response to active permafrost thaw.</p>

Research paper thumbnail of Standardized monitoring of permafrost thaw: a user-friendly, multiparameter protocol (T-MOSAiC)

Climate change is destabilizing permafrost landscapes, affecting infrastructure, ecosystems, and ... more Climate change is destabilizing permafrost landscapes, affecting infrastructure, ecosystems, and human livelihoods. The rate of permafrost thaw is controlled by surface and subsurface properties and processes, all of which are potentially linked with each other. However, no standardized protocol exists for measuring permafrost thaw and related processes and properties in a linked manner. The permafrost thaw action group of the Terrestrial Multidisciplinary distributed Observatories for the Study of the Arctic Connections (T-MOSAiC) project has developed a protocol, for use by non-specialist scientists and technicians, citizen scientists, and indigenous groups, to collect standardized metadata and data on permafrost thaw. The protocol introduced here addresses the need to jointly measure permafrost thaw and the associated surface and subsurface environmental conditions. The parameters measured along transects include: snow depth, thaw depth, vegetation height, soil texture, and water level. The metadata collection includes data on timing of data collection, geographical coordinates, land surface characteristics (vegetation, ground surface, water conditions), as well as photographs. Our hope is that this openly

Research paper thumbnail of Intraspecific trait variability is a key feature underlying high Arctic plant community resistance to climate warming

Ecological Monographs, Dec 9, 2022

Research paper thumbnail of The role of plant functional groups mediating climate impacts on carbon and biodiversity of alpine grasslands

Scientific Data, Jul 28, 2022

Plant removal experiments allow assessment of the role of biotic interactions among species or fu... more Plant removal experiments allow assessment of the role of biotic interactions among species or functional groups in community assembly and ecosystem functioning. When replicated along climate gradients, they can assess changes in interactions among species or functional groups with climate. Across twelve sites in the Vestland Climate Grid (VCG) spanning 4 °C in growing season temperature and 2000 mm in mean annual precipitation across boreal and alpine regions of Western Norway, we conducted a fully factorial plant functional group removal experiment (graminoids, forbs, bryophytes). Over six years, we recorded biomass removed, soil microclimate, plant community composition and structure, seedling recruitment, ecosystem carbon fluxes, and reflectance in 384 experimental and control plots. The dataset consists of 5,412 biomass records, 360 species-level biomass records, 1,084,970 soil temperature records, 4,771 soil moisture records, 17,181 plant records covering 206 taxa, 16,656 seedling records, 3,696 ecosystem carbon flux measurements, and 1,244 reflectance measurements. The data can be combined with longer-term climate data and plant population, community, ecosystem, and functional trait data collected within the VCG.

Research paper thumbnail of Explicitly modelling microtopography in permafrost landscapes in a land surface model (JULES vn5.4_microtopography)

Geoscientific Model Development, May 6, 2022

Research paper thumbnail of Climate–ecosystem modelling made easy: The Land Sites Platform

Global Change Biology

Dynamic Global Vegetation Models (DGVMs) provide a state‐of‐the‐art process‐based approach to stu... more Dynamic Global Vegetation Models (DGVMs) provide a state‐of‐the‐art process‐based approach to study the complex interplay between vegetation and its physical environment. For example, they help to predict how terrestrial plants interact with climate, soils, disturbance and competition for resources. We argue that there is untapped potential for the use of DGVMs in ecological and ecophysiological research. One fundamental barrier to realize this potential is that many researchers with relevant expertize (ecology, plant physiology, soil science, etc.) lack access to the technical resources or awareness of the research potential of DGVMs. Here we present the Land Sites Platform (LSP): new software that facilitates single‐site simulations with the Functionally Assembled Terrestrial Ecosystem Simulator, an advanced DGVM coupled with the Community Land Model. The LSP includes a Graphical User Interface and an Application Programming Interface, which improve the user experience and lower t...

Research paper thumbnail of Disaggregating the carbon exchange of degrading permafrost peatlands using Bayesian deep learning

Extensive regions in the permafrost zone are projected to become climatically unsuitable to susta... more Extensive regions in the permafrost zone are projected to become climatically unsuitable to sustain permafrost peatlands over the next century, suggesting transformations in these landscapes that can leave large amounts of permafrost carbon vulnerable to post-thaw decomposition. We present three years of eddy covariance measurements of CH4 and CO2 fluxes from the degrading permafrost peatland Iskoras in Northern Norway, which we disaggregate into separate fluxes of palsa, pond, and fen areas using information provided by the dynamic flux footprint in a novel ensemble-based Bayesian deep neural network framework. The three-year mean CO2-equivalent flux is estimated to be 106 gCO2 m-2 yr-1 for palsas, 1780 gCO2 m-2 yr-1 for ponds, and -31 gCO2 m-2 yr-1 for fens, indicating that possible palsa degradation to thermokarst ponds would strengthen the local greenhouse gas forcing by a factor of about 17, while transformation into fens would slightly reduce the current local greenhouse gas f...

Research paper thumbnail of Bryophytes dominate plant regulation of soil microclimate in alpine grasslands

Oikos

Soil temperature and moisture are important regulators of a broad range of biotic and abiotic pro... more Soil temperature and moisture are important regulators of a broad range of biotic and abiotic processes in terrestrial ecosystems. Vegetation can, in turn, play a role in regulating soil microclimate, which creates potential for powerful and interactive feedbacks from soil and vegetation on the atmosphere. Although the regulatory effect of vegetation on soil microclimatic conditions has been quite extensively and empirically assessed, most studies have determined the net effect of intact woody vegetation versus bare ground. However, for other plant functional groups we lack a clear understanding of their role and any climate‐context dependency in controlling microclimatic conditions.We investigated the role of three major plant functional groups – graminoids, forbs and bryophytes – in regulating soil microclimate in semi‐natural alpine grasslands. Using a fully factorial above‐ground biomass removal experiment, we assessed the role of these plant functional groups in regulating soil...

Research paper thumbnail of Volatile organic compound release across a permafrost-affected peatland

Research paper thumbnail of The role of plant functional groups mediating climate impacts on carbon and biodiversity of alpine grasslands

Scientific Data

Plant removal experiments allow assessment of the role of biotic interactions among species or fu... more Plant removal experiments allow assessment of the role of biotic interactions among species or functional groups in community assembly and ecosystem functioning. When replicated along climate gradients, they can assess changes in interactions among species or functional groups with climate. Across twelve sites in the Vestland Climate Grid (VCG) spanning 4 °C in growing season temperature and 2000 mm in mean annual precipitation across boreal and alpine regions of Western Norway, we conducted a fully factorial plant functional group removal experiment (graminoids, forbs, bryophytes). Over six years, we recorded biomass removed, soil microclimate, plant community composition and structure, seedling recruitment, ecosystem carbon fluxes, and reflectance in 384 experimental and control plots. The dataset consists of 5,412 biomass records, 360 species-level biomass records, 1,084,970 soil temperature records, 4,771 soil moisture records, 17,181 plant records covering 206 taxa, 16,656 seed...

Research paper thumbnail of Multiscale mapping of plant functional groups and plant traits in the High Arctic using field spectroscopy, UAV imagery and Sentinel-2A data

Environmental Research Letters, 2021

The Arctic is warming twice as fast as the rest of the planet, leading to rapid changes in specie... more The Arctic is warming twice as fast as the rest of the planet, leading to rapid changes in species composition and plant functional trait variation. Landscape-level maps of vegetation composition and trait distributions are required to expand spatially-limited plot studies, overcome sampling biases associated with the most accessible research areas, and create baselines from which to monitor environmental change. Unmanned aerial vehicles (UAVs) have emerged as a low-cost method to generate high-resolution imagery and bridge the gap between fine-scale field studies and lower resolution satellite analyses. Here we used field spectroscopy data (400–2500 nm) and UAV multispectral imagery to test spectral methods of species identification and plant water and chemistry retrieval near Longyearbyen, Svalbard. Using the field spectroscopy data and Random Forest analysis, we were able to distinguish eight common High Arctic plant tundra species with 74% accuracy. Using partial least squares r...

Research paper thumbnail of Intraspecific trait variability is a key feature underlying high Arctic plant community resistance to climate warming

Research paper thumbnail of Standardized monitoring of permafrost thaw: a user-friendly, multiparameter protocol (T-MOSAiC)

EPIC3Svalbard Science Conference 2021, 2021-11-02-2021-11-03, Nov 3, 2021

Research paper thumbnail of Supplementary material to "Explicitly modelling microtopography in permafrost landscapes in a land-surface model (JULES vn5.4_microtopography)

Research paper thumbnail of Trait Shifts affect Ecosystem Carbon Exchange under Climate Change in Alpine Grasslands

AGU Fall Meeting Abstracts, Dec 1, 2018

Research paper thumbnail of Volatile carbon emissions from a degrading permafrost peatland

<p>Permafrost in the north Polar Regions stores more than 1,500 Pg of organ... more <p>Permafrost in the north Polar Regions stores more than 1,500 Pg of organic carbon, which is nearly twice as much as the atmospheric carbon pool. As the Arctic region is experiencing unprecedented warming, accelerated decomposition in permafrost is potentially switching it to a hotspot of carbon emissions. In addition to the widely studies carbon dioxide and methane, permafrost may also be a source of biogenic volatile organic compounds (BVOCs), a reactive group of trace gases which have so far received much less attention. BVOCs can prolong the lifetime of methane through the depletion of hydroxyl radicals, contribute to ozone formation, and lead to the formation of secondary organic aerosol, and thus exert significant impact on climate forcing, especially in unpolluted Arctic region.</p><p>Here, we conducted in situ measurements of soil BVOC emissions on an actively degrading permafrost peatland during a growing season. We compared emissions along a gradient of landscape units from soil palsa and vegetated palsa to thaw slump, thaw pond and vegetated thaw pond. BVOC samples were collected onto absorbent cartridges using dynamic enclosure chamber method, and then analyzed with a gas chromatograph coupled with a mass spectrometer (GC/MS), based upon which the emission rates were calculated.</p><p>Results suggested that all landscapes units across the peatland showed net emissions of BVOCs during the summertime. Major BVOC groups included monoterpenes, sesquiterpenes, isoprene, hydrocarbons, methanol, acetone, other oxygenated VOCs and other compounds, and these groups were present in all landscape units. All VOC groups also exhibited seasonal and spatial variations across the different sampling months and landscape units. For example, the actively degrading thaw slump showed higher monoterpene emissions that other landscape units, while sesquiterpene emissions were highest from the vegetated thaw ponds. Principal component analysis further revealed temporal and spatial patterns in the relative compositions of the BVOC profiles. Our results show that soil BVOC emissions change in response to active permafrost thaw.</p>

Research paper thumbnail of Long lasting greenhouse gas emissions beyond abrupt permafrost thaw event in permafrost peatlands

<p>Abrupt permafrost thawing is expected to release large amounts o... more <p>Abrupt permafrost thawing is expected to release large amounts of greenhouse gasses to the atmosphere, creating a positive feedback to climate warming. There is, however, still large uncertainty in the timing, duration, magnitude, and mechanisms controlling this process, which hampers accurate quantification of permafrost carbon climate feedback cycles. The current understanding supports that abrupt permafrost thaw will lead to surface inundation and create anaerobic landscapes, which dominantly produce methane during the decomposition process. Over time, natural succession and vegetation growth may decrease methane release and increase net carbon uptake. We investigated how rapid permafrost thawing and subsequent natural succession over time affect CO<sub>2</sub>, CH<sub>4</sub>, and N<sub>2</sub>O release at a field site in northern Norway (69ᵒN), where recent abrupt degradation of permafrost created thaw ponds in palsa peat plateau-mire ecosystems. The site exhibits a natural gradient of permafrost thaw, which also corresponds to a strong hydrological gradient (i.e. dry peat plateau underlain by intact permafrost, seasonally inundated thaw slumps, thaw ponds, and natural succession ponds covered by sphagnum and sedges). Since 2017, we used a range of manual and automated techniques to measure changes in vegetation, soil and water microclimate, biogeochemistry, and soil CO<sub>2</sub>, CH<sub>4</sub>, and N<sub>2</sub>O concentrations and fluxes across the permafrost thaw gradient. In the three-year observations, we show that abrupt permafrost thaw and land surface subsidence – both intermediate slumping and pond formation – increase net annual carbon loss. Permafrost thaw accelerated CO<sub>2</sub> release greatly in thaw slumps (177.5 gCO<sub>2</sub> m<sup>-2</sup>) compared to intact permafrost peat plateau (59.0 gCO<sub>2</sub> m<sup>-2</sup>). During the growing season, peat plateau was a small sink of atmospheric CH<sub>4</sub> (-2.5 gCH<sub>4</sub> m<sup>-2</sup>), whereas permafrost thaw slumping and pond formation increased CH<sub>4</sub> release dramatically (ranging from 9.7 to 36.1 gCH<sub>4</sub> m<sup>-2</sup>). Furthermore, CH<sub>4</sub> release continues to increase even in natural succession pond likely due to aerenchyma transport of CH<sub>4</sub> from deeper soil. The overall N<sub>2</sub>O release was negligeable except in the bare soil peat plateau. The net radiative forcing of ecosystem carbon balance will depend on the carbon uptake from the natural succession of vegetation, but we show that greenhouse gas emissions continue to increase beyond abrupt permafrost thaw event towards natural succession.</p>