Anna‐Maria Virkkala
A5067168915- Climate change and permafrost
- Cryospheric studies and observations
- Atmospheric and Environmental Gas Dynamics
- Geology and Paleoclimatology Research
- Methane Hydrates and Related Phenomena
- Peatlands and Wetlands Ecology
- Isotope Analysis in Ecology
- Geological Studies and Exploration
- Polar Research and Ecology
- Climate variability and models
- Indigenous Studies and Ecology
- Plant Water Relations and Carbon Dynamics
- Landslides and related hazards
- Microbial Community Ecology and Physiology
- Hydrocarbon exploration and reservoir analysis
- Radiomics and Machine Learning in Medical Imaging
- Fire effects on ecosystems
- Tree-ring climate responses
- Smart Materials for Construction
- Ecology and Vegetation Dynamics Studies
- Air Quality Monitoring and Forecasting
- Botany and Plant Ecology Studies
- Radioactive contamination and transfer
- Rangeland and Wildlife Management
- Soil Carbon and Nitrogen Dynamics
Woodwell Climate Research Center
2019-2025
University of Helsinki
2017-2024
Bolin Centre for Climate Research
2024
Stockholm University
2024
Abstract The regional variability in tundra and boreal carbon dioxide (CO 2 ) fluxes can be high, complicating efforts to quantify sink‐source patterns across the entire region. Statistical models are increasingly used predict (i.e., upscale) CO large spatial domains, but reliability of different modeling techniques, each with specifications assumptions, has not been assessed detail. Here, we compile eddy covariance chamber measurements annual growing season gross primary productivity (GPP),...
Abstract Significant progress in permafrost carbon science made over the past decades include identification of vast stocks, development new pan‐Arctic maps, an increase terrestrial measurement sites for CO 2 and methane fluxes, important factors affecting cycling, including vegetation changes, periods soil freezing thawing, wildfire, other disturbance events. Process‐based modeling studies now key elements cycling advances statistical inverse enhance understanding region C budgets. By...
Abstract The northern permafrost region has been projected to shift from a net sink source of carbon under global warming. However, estimates the contemporary greenhouse gas (GHG) balance and budgets remain highly uncertain. Here, we construct first comprehensive bottom‐up CO 2 , CH 4 N O across terrestrial using databases more than 1000 in situ flux measurements land cover‐based ecosystem upscaling approach for period 2000–2020. Estimates indicate that emitted mean annual 12 (−606, 661) Tg...
Abstract Tundra and boreal ecosystems encompass the northern circumpolar permafrost region are experiencing rapid environmental change with important implications for global carbon (C) budget. We analysed multi-decadal time series containing 302 annual estimates of dioxide (CO 2 ) flux across 70 non-permafrost ecosystems, 672 summer CO 181 ecosystems. find an increase in sink but not despite similar increases uptake. Thus, recent non-growing-season losses have substantially impacted balance...
Abstract The Arctic–Boreal Zone is rapidly warming, impacting its large soil carbon stocks. Here we use a new compilation of terrestrial ecosystem CO 2 fluxes, geospatial datasets and random forest models to show that although the was overall an increasing sink from 2001 2020 (mean ± standard deviation in net exchange, −548 140 Tg C yr −1 ; trend, −14 P < 0.001), more than 30% region source. Tundra regions may have already started function on average as sources, demonstrating shift...
Abstract In the tundra, woody plants are dispersing towards higher latitudes and altitudes due to increasingly favourable climatic conditions. The coverage height of increasing, which may influence soils tundra ecosystem. Here, we use structural equation modelling analyse 171 study plots examine if affect growing-season topsoil moisture temperature (< 10 cm) as well soil organic carbon stocks 80 cm). our setting, consider hierarchy ecosystem by controlling for other factors, such...
Abstract. Large changes in the Arctic carbon balance are expected as warming linked to climate change threatens destabilize ancient permafrost stocks. The eddy covariance (EC) method is an established technique quantify net losses and gains of between biosphere atmosphere at high spatiotemporal resolution. Over past decades, a growing network terrestrial EC tower sites has been across Arctic, but comprehensive assessment network's representativeness within heterogeneous region still lacking....
Abstract. Past efforts to synthesize and quantify the magnitude change in carbon dioxide (CO2) fluxes terrestrial ecosystems across rapidly warming Arctic–boreal zone (ABZ) have provided valuable information but were limited their geographical temporal coverage. Furthermore, these been based on data aggregated over varying time periods, often with only minimal site ancillary data, thus limiting potential be used large-scale budget assessments. To bridge gaps, we developed a standardized...
Abstract Background In contrast to earlier assumptions, there is now mounting evidence for the role of tundra soils as important sources greenhouse gas nitrous oxide (N 2 O). However, microorganisms involved in cycling N O this system remain largely uncharacterized. Since are variable and sinks O, we aimed at investigating differences community structure across different soil ecosystems tundra. Results We analysed 1.4 Tb metagenomic data from northern Finland covering a range dry upland...
Abstract Ecosystems in the North American Arctic-Boreal Zone (ABZ) experience a diverse set of disturbances associated with wildfire, permafrost dynamics, geomorphic processes, insect outbreaks and pathogens, extreme weather events, human activity. Climate warming ABZ is occurring at over twice rate global average, as result extent, frequency, severity these are increasing rapidly. Disturbances span wide gradient spatiotemporal scales have varying impacts on ecosystem properties function....
Abstract The trait composition and diversity of plant communities are globally applicable predictors ecosystem functioning. Yet, it is unclear how traits influence carbon cycling. This an important question in the tundra where vegetation shifts occurring across entire biome, soil organic stocks large vulnerable to environmental change. To study affect cycling tundra, we built a model that explained (above‐ground stocks, photosynthetic respiratory fluxes) with abiotic conditions (air...
Arctic wetlands are known methane (CH
Abstract Motivation The Tundra Trait Team (TTT) database includes field‐based measurements of key traits related to plant form and function at multiple sites across the tundra biome. This dataset can be used address theoretical questions about strategy trade‐offs, trait–environment relationships environmental filtering, trait variation spatial scales, validate satellite data, inform Earth system model parameters. Main types variable contained contains 91,970 18 traits. most frequently...
The Arctic tundra plays an important role in the carbon cycle as it stores 50% of global soil organic reservoirs. processes (fluxes) regulating these stocks are predicted to change due direct and indirect effects climate change. Understanding current future balance calls for a summary level knowledge regarding chamber-derived dioxide (CO 2 ) flux studies. Here, we describe progress from recently (2000–2016) published studies growing-season CO chamber measurements, namely GPP (gross primary...
Warming of northern high latitude regions (NHL, > 50 °N) has increased both photosynthesis and respiration which results in considerable uncertainty regarding the net carbon dioxide (CO2) balance NHL ecosystems. Using estimates constrained from atmospheric observations 1980 to 2017, we find that increasing trends CO2 uptake early-growing season are similar magnitude across tree cover gradient NHL. However, trend respiratory loss during late-growing increases significantly with cover,...
Abstract Plant biomass is a fundamental ecosystem attribute that sensitive to rapid climatic changes occurring in the Arctic. Nevertheless, measuring plant Arctic logistically challenging and resource intensive. Lack of accessible field data hinders efforts understand amount, composition, distribution, these northern ecosystems. Here, we present The aboveground synthesis dataset , which includes measurements lichen, bryophyte, herb, shrub, and/or tree (g m −2 ) on 2,327 sample plots from 636...
Litter decomposition is a key process for carbon and nutrient cycling in terrestrial ecosystems mainly controlled by environmental conditions, substrate quantity quality as well microbial community abundance composition. In particular, the effects of climate atmospheric nitrogen (N) deposition on litter its temporal dynamics are significant importance, since their might change over course process. Within TeaComposition initiative, we incubated Green Rooibos teas at 524 sites across nine...
Abstract. Arctic terrestrial greenhouse gas (GHG) fluxes of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) play an important role in the global GHG budget. However, these are rarely studied simultaneously, our understanding conditions controlling them across spatial gradients is limited. Here, we explore magnitudes drivers fine-scale during peak growing season (July) sub-Arctic Finland. We measured chamber-derived soil temperature, moisture, organic nitrogen stocks, pH,...
Abstract Global warming is driving environmental change in the Arctic. However, our current understanding of this varies strongly among different disciplines and limited by number distribution field sampling locations. Here, we use a quantitative framework based on multivariate statistical modeling to present state across We utilize an existing database georeferenced Arctic studies investigate how locations citations are distributed topographical, soil vegetation conditions, highlight...
Due to climate change, increased microbial activity in high-latitude soils may lead higher greenhouse gas (GHG) emissions. However, GHG production and consumption mechanisms tundra are not thoroughly understood. To investigate how the diversity functional potential of bacterial archaeal communities vary across vegetation types soil layers, we analyzed 116 metatranscriptomes from 73 sites Finnish sub-Arctic. Meadow were characterized by pH lower organic matter (SOM) carbon/nitrogen ratio. By...
Abstract. Arctic terrestrial greenhouse gas (GHG) fluxes of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) play an important role in the global GHG budget. However, these are rarely studied simultaneously, our understanding conditions controlling them across spatial gradients is limited. Here, we explore magnitudes drivers fine-scale during peak growing season (July) sub-Arctic Finland. We measured chamber-derived soil temperature, moisture, organic nitrogen stocks, pH,...
Abstract The high latitudes cover ∼20% of Earth's land surface. This region is facing many shifts in thermal, moisture and vegetation properties, driven by climate warming. Here we leverage remote sensing reanalysis records to improve understanding changes ecosystem indicators. We applied non‐parametric trend detections Getis‐Ord Gi* spatial hotspot assessments. found substantial terrestrial warming trends across Siberia, portions Greenland, Alaska, western Canada. same regions showed...
Nitrous oxide (N&#8322;O) is one of the most important greenhouse gases (GHG) with a global warming potential about 298 times stronger than carbon dioxide (CO&#8322;) over period 100 years. While N&#8322;O emissions are released from natural ecosystems (60%), research has focussed largely on nutrient-rich agricultural soils, leading to lack understanding nutrient-poor (sub-) Arctic ecosystems. Recent findings indicated significant organic-rich resulting in bias towards high...
Arctic regions play a critical role in the global carbon cycle, acting as both sink and source of carbon. However, it remains challenging to estimate methane (CH4) dioxide (CO2) fluxes across landscapes due sparsity measurements complex interactions between environmental factors. Upscaling from local broader is challenging, especially capturing variability land cover types their unique dynamics. Addressing this heterogeneity improving flux estimates reducing uncertainties budgets.Our study...
Abstract. Nitrous oxide (N2O) is the third most important greenhouse gas, with its atmospheric concentration rising from 273 parts per billion (ppb) to 336 ppb since 1800, primarily due agricultural activities. However, nutrient-poor natural soils, including those in sub-Arctic, also emit and consume N2O. These soils have not been studied extensively, partly challenges reliably detecting low fluxes. Methodological limitations were largely influenced by available instrumentation; lack of...