scholarly journals Net greenhouse gas fluxes from three High Arctic plant communities along a moisture gradient

2019 ◽  
Vol 5 (4) ◽  
pp. 185-201 ◽  
Author(s):  
Ioan Wagner ◽  
Jacqueline K.Y. Hung ◽  
Allison Neil ◽  
Neal A. Scott
Keyword(s):  
Greenhouse Gas ◽  
Vegetation Cover ◽  
High Arctic ◽  
Moisture Gradient ◽  
Gas Production ◽  
The Arctic ◽  
Environmental Drivers ◽  
Arctic Ecosystems ◽  
Gas Fluxes ◽  
Tundra Ecosystem

Climate in high latitude environments is predicted to undergo a pronounced warming and increase in precipitation, which may influence the terrestrial moisture gradients that affect vegetation distribution. Vegetation cover can influence rates of greenhouse gas production through differences in microbial communities, plant carbon uptake potential, and root transport of gases out of the soil into the atmosphere. To predict future changes in greenhouse gas production from High Arctic ecosystems in response to climate change, it is important to understand the interaction between trace gas fluxes and vegetation cover. During the growing seasons of 2008 and 2009, we used dark static chambers to measure CH4 and N2O fluxes and CO2 emissions at Cape Bounty, Melville Island, NU, across a soil moisture gradient, as reflected by their vegetation cover. In both years, wet sedge had the highest rates of emission for all trace gases, followed by the mesic tundra ecosystem. CH4 consumption was highest in the polar semi-desert, correlating positively with temperature and negatively with moisture. Our findings demonstrate that net CH4 uptake may be largely underestimated across the Arctic due to sampling bias towards wetlands. Overall, greenhouse gas flux responses vary depending on different environmental drivers, and the role of vegetation cover needs to be considered in predicting the trajectory of greenhouse gas uptake and release in response to a changing climate.

Temperature Sensitivity of Soil Greenhouse Gas Production in Three High‐Arctic Plant Community Types at Cape Bounty, Nunavut

2016 ◽  
Author(s):  
Evangeline Fisher
Keyword(s):  
Greenhouse Gas ◽  
Plant Community ◽  
Temperature Sensitivity ◽  
High Arctic ◽  
Gas Production ◽  
Climate System ◽  
Arctic Ecosystems ◽  
Polar Desert ◽  
Community Types ◽  
Q10 Values

Enhanced precipitation and higher temperatures are expected in the Arctic as the result of future climatic warming. To understand future contributions of high‐arctic ecosystems to the climate system, we need to understand the feedbacks between climate and greenhouse gas production, and how they might vary between plant community types distributed along soil moisture gradients. We incubated intact soil cores in the laboratory to explore the temperature sensitivity of soil greenhouse gas (CO2, CH4, N2O) production across the three main plant community types of Cape Bounty, Nunavut: polar desert, mesic tundra and wet sedge. Two sets of cores (0‐10 cm mineral soil) were incubated in the laboratory at 4, 8, and 12°C for one month. We also measured plant community differences in soil thermal regimes for one year. Mean field temperatures were highest in the polar desert during the summer months, while temperatures in the mesic tundra were lowest during this time. In the winter, soil temperatures were lowest in the polar desert and highest in the wet sedge communities. Initial incubation results demonstrate Q10 values for CO2 production ranging from 2.18 in wet sedge to 8.67 in polar desert soils. We observed a Q10 of 4.03 for CH4 output in mesic tundra soils and a Q10 of 16.42 for N2O output in wet sedge soils. Our results suggest that use of single Q10 values to predict future greenhouse gas emissions from high‐arctic ecosystems would likely underestimate the contribution of these ecosystems to the global climate system in a warmer climate.

scholarly journals Soil microbial biomass, activity and community composition along altitudinal gradients in the High Arctic (Billefjorden, Svalbard)

2018 ◽  
Vol 15 (6) ◽  
pp. 1879-1894 ◽  
Author(s):  
Petr Kotas ◽  
Hana Šantrůčková ◽  
Josef Elster ◽  
Eva Kaštovská
Keyword(s):  
Community Structure ◽  
Microbial Biomass ◽  
High Arctic ◽  
The Arctic ◽  
Soil Parameters ◽  
Organic Carbon Content ◽  
Soil Microbial ◽  
Environmental Controls ◽  
Arctic Soils ◽  
Tundra Ecosystem

Abstract. The unique and fragile High Arctic ecosystems are vulnerable to global climate warming. The elucidation of factors driving microbial distribution and activity in arctic soils is essential for a comprehensive understanding of ecosystem functioning and its response to environmental change. The goals of this study were to investigate microbial biomass and activity, microbial community structure (MCS), and their environmental controls in soils along three elevational transects in the coastal mountains of Billefjorden, central Svalbard. Soils from four different altitudes (25, 275, 525 and 765 m above sea level) were analyzed for a suite of characteristics including temperature regimes, organic matter content, base cation availability, moisture, pH, potential respiration, and microbial biomass and community structure using phospholipid fatty acids (PLFAs). We observed significant spatial heterogeneity of edaphic properties among transects, resulting in transect-specific effects of altitude on most soil parameters. We did not observe any clear elevation pattern in microbial biomass, and microbial activity revealed contrasting elevational patterns between transects. We found relatively large horizontal variability in MCS (i.e., between sites of corresponding elevation in different transects), mainly due to differences in the composition of bacterial PLFAs, but also a systematic altitudinal shift in MCS related to different habitat preferences of fungi and bacteria, which resulted in high fungi-to-bacteria ratios at the most elevated sites. The biological soil crusts on these most elevated, unvegetated sites can host microbial assemblages of a size and activity comparable to those of the arctic tundra ecosystem. The key environmental factors determining horizontal and vertical changes in soil microbial properties were soil pH, organic carbon content, soil moisture and Mg2+ availability.

Does Diapirism Influence Greenhouse Gas Production on Patterned Ground in the High Arctic?

2015 ◽  
Vol 79 (3) ◽  
pp. 889-895 ◽  
Author(s):  
Martin E. Brummell ◽  
Amanda Guy ◽  
Steven D. Siciliano
Keyword(s):  
Greenhouse Gas ◽  
High Arctic ◽  
Gas Production ◽  
Patterned Ground

Seasonal change and microhabitat association of Arctic spider assemblages (Arachnida: Araneae) on Victoria Island (Nunavut, Canada)

2017 ◽  
Vol 149 (3) ◽  
pp. 357-371 ◽  
Author(s):  
Elyssa R. Cameron ◽  
Christopher M. Buddle
Keyword(s):  
Seasonal Change ◽  
Ecological Monitoring ◽  
High Arctic ◽  
The Arctic ◽  
Arctic Ecosystems ◽  
Active Season ◽  
The North ◽  
Arthropod Predators ◽  
Abundance And Diversity ◽  
Victoria Island

AbstractArctic ecosystems are characterised by a mosaic of distinct microhabitats, which play a key role in structuring biodiversity. Understanding species diversity in relation to these microhabitats, and how communities are structured seasonally, is imperative to properly conserve, monitor, and manage northern biodiversity. Spiders (Arachnida: Araneae) are dominant arthropod predators in the Arctic, yet the seasonal change in their communities in relation to microhabitat variation is relatively unknown. This research quantified how spider assemblages are structured seasonally and by microhabitat, near Cambridge Bay, Nunavut, Canada. In 2014, spiders were collected in 240 pan and pitfall traps placed in common microhabitat types (two wet and two dry) from 3 July to 11 August, the active season in the high Arctic. In total, 10 353 spiders from 22 species and four families were collected. Non-metric multidimensional scaling ordinations revealed that spider assemblages from wet habitats were distinct from those occurring in drier habitats, but that differences within each of those habitats were not evident. Abundance and diversity was highest in wet habitats and differed significantly from dry habitats; both these variables decreased seasonally. Spider assemblages in the north are structured strongly along moisture gradients, and such data informs planning for future ecological monitoring in the Arctic.

scholarly journals Abundance, habitat use and food consumption of seabirds in the high-Arctic fjord ecosystem

Polar Biology ◽  
2021 ◽  
Vol 44 (4) ◽  
pp. 739-750
Author(s):  
Lech Stempniewicz ◽  
Michał Goc ◽  
Marta Głuchowska ◽  
Dorota Kidawa ◽  
Jan Marcin Węsławski
Keyword(s):  
High Arctic ◽  
Pelagic Zone ◽  
The Arctic ◽  
Arctic Ecosystems ◽  
Rissa Tridactyla ◽  
Arctic Fjord ◽  
Main Components ◽  
And Function ◽  
Arctic Food Web ◽  
Induced Changes

AbstractTo monitor the rapid changes occurring in Arctic ecosystems and predict their direction, basic information about the current number and structure of the main components of these systems is necessary. Using boat-based surveys, we studied the numbers and distribution of seabirds foraging in Hornsund (SW Spitsbergen) during three summer seasons. The average number of seabirds foraging concurrently in the whole fjord was estimated at 28,000. Little Auks Alle alle were the most numerous, followed by Northern Fulmars Fulmarus glacialis, Brünnich’s Guillemots Uria lomvia and Black-legged Kittiwakes Rissa tridactyla. The pelagic zone was exploited by some 75% of the birds. Their density was the highest (> 400 ind. km−2) in the tidewater glacier bays, where kittiwakes were predominant, and the lowest in the coastal glacier bays. The seabirds in Hornsund daily consumed c. 12.7 tons of food, i.e. c. 0.2% of the summer mesozooplankton and fish standing stocks available in the fjord. This food consisted primarily of copepods, amphipods and molluscs (c. 70%), whereas fish made up < 15%. More than 50% of this biomass was ingested by pursuit divers, while surface feeders took c. 29% and benthophages c. 13%. About three-quarters of the food biomass was taken from the pelagic zone. This paper describes, for the first time in quantitative terms, the structure and function of a seabird community foraging in an Arctic fjord. It also provides a baseline for future studies on climate-induced changes in the importance of seabirds in the Arctic food web.

scholarly journals Birds of three worlds: moult migration to high Arctic expands a boreal-temperate flyway to a third biome

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Antti Piironen ◽  
Antti Paasivaara ◽  
Toni Laaksonen
Keyword(s):  
Bird Migration ◽  
High Arctic ◽  
The Arctic ◽  
Migratory Connectivity ◽  
Migration Routes ◽  
Arctic Ecosystems ◽  
Long Distance ◽  
Novaya Zemlya ◽  
Bean Goose ◽  
Moult Migration

Abstract Background Knowledge on migration patterns and flyways is a key for understanding the dynamics of migratory populations and evolution of migratory behaviour. Bird migration is usually considered to be movements between breeding and wintering areas, while less attention has been paid to other long-distance movements such as moult migration. Methods We use high-resolution satellite-tracking data from 58 taiga bean geese Anser fabalis fabalis from the years 2019–2020, to study their moult migration during breeding season. We show the moulting sites, estimate the migratory connectivity between the breeding and the moulting sites, and estimate the utilization distributions during moult. We reveal migration routes and compare the length and timing of migration between moult migrants and successful breeders. Results All satellite-tracked non-breeding and unsuccessfully breeding taiga bean geese migrated annually to the island of Novaya Zemlya in the high Arctic for wing moult, meaning that a large part of the population gathers at the moulting sites outside the breeding range annually for approximately three months. Migratory connectivity between breeding and moulting sites was very low (rm =  − 0.001, 95% CI − 0.1562–0.2897), indicating that individuals from different breeding grounds mix with each other on the moulting sites. Moult migrants began fall migration later in autumn than successful breeders, and their overall annual migration distance was over twofold compared to the successful breeders. Conclusions Regular moult migration makes the Arctic an equally relevant habitat for the taiga bean goose population as their boreal breeding and temperate wintering grounds, and links ecological communities in these biomes. Moult migration plays an important role in the movement patterns and spatio-temporal distribution of the population. Low migratory connectivity between breeding and moulting sites can potentially contribute to the gene flow within the population. Moult migration to the high Arctic exposes the population to the rapid impacts of global warming to Arctic ecosystems. Additionally, Novaya Zemlya holds radioactive contaminants from various sources, which might still pose a threat to moult migrants. Generally, these results show that moult migration may essentially contribute to the way we should consider bird migration and migratory flyways.

The Effects of Predicted Soil Moisture and Temperature Increase on CO2 Exchange within a High Arctic Ecosystem

2018 ◽  
Author(s):  
Sarah Jackson
Keyword(s):  
Soil Moisture ◽  
Soil Temperature ◽  
Co2 Flux ◽  
High Arctic ◽  
Co2 Exchange ◽  
The Arctic ◽  
Co2 Production ◽  
Arctic Ecosystems ◽  
Arctic Regions ◽  
Snow Fences

With 2014 being the warmest year on record and 10 of the warmest years occurring after 1997, it is essential to understand the effects of this warming on CO2 exchange. It was also discovered that much of this warming is focused in the Arctic regions, which are sensitive to changes in temperature (Cole & McCarthy, 2015). My research examines the effects of enhanced snowfall and soil temperature on the exchange of CO2 between the land and the atmosphere in a high arctic environment. The research is taking place at Cape Bounty Arctic Watershed Observatory (CBAWO) on Melville Island, Nunavut as part of the International Tundra Experiment (ITEX). The goal of ITEX is to better understand the effects of increased summer temperature and increased snowfall on arctic ecosystems. This is a full factorial experiment including treatments varying precipitation (and likely soil moisture), soil temperature, moisture and temperature together, and a control that is at ambient soil moisture and temperature. Snow fences are used to enhance precipitation, while open-topped transparent chambers are used to increase soil temperature. In a companion lab experiment, I look at the effects of different soil moisture levels and temperatures on soil CO2 production in a more controlled environment. Two temperatures, two moisture levels, and eight replicates of each will be established in sealed incubation chambers, and soils will be incubated for 33 days. Presently a significant relationship has been found between soil moisture and CO2 flux within the field experiment.

scholarly journals Changes in coupled carbon‒nitrogen dynamics in a tundra ecosystem predate post-1950 regional warming

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
N. John Anderson ◽  
Daniel R. Engstrom ◽  
Peter R. Leavitt ◽  
Sarah M. Flood ◽  
Adam J. Heathcote
Keyword(s):  
Nutrient Dynamics ◽  
Synergistic Effects ◽  
Sediment Cores ◽  
Terrestrial Ecosystems ◽  
N Deposition ◽  
Environmental Drivers ◽  
Arctic Ecosystems ◽  
Regional Warming ◽  
The North ◽  
Tundra Ecosystem

Abstract Arctic ecosystems are changing in response to recent rapid warming, but the synergistic effects of other environmental drivers, such as moisture and atmospheric nitrogen (N) deposition, are difficult to discern due to limited monitoring records. Here we use geochemical analyses of 210Pb-dated lake-sediment cores from the North Slope of Alaska to show that changes in landscape nutrient dynamics started over 130 years ago. Lake carbon burial doubled between 1880 and the late-1990s, while current rates (~10 g C m−2 yr−1) represent about half the CO2 emission rate for tundra lakes. Lake C burial reflects increased aquatic production, stimulated initially by nutrients from terrestrial ecosystems due to late-19th century moisture-driven changes in soil microbial processes and, more recently, by atmospheric reactive N deposition. These results highlight the integrated response of Arctic carbon cycling to global environmental stressors and the degree to which C–N linkages were altered prior to post-1950 regional warming.

scholarly journals Microscale drivers of summer CO2 fluxes in the Svalbard High Arctic tundra

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Marta Magnani ◽  
Ilaria Baneschi ◽  
Mariasilvia Giamberini ◽  
Brunella Raco ◽  
Antonello Provenzale
Keyword(s):  
Ecosystem Respiration ◽  
Vegetation Type ◽  
Gross Primary Production ◽  
Arctic Tundra ◽  
High Arctic ◽  
The Arctic ◽  
Small Scale ◽  
Arctic Ecosystems ◽  
Additional Source ◽  
And Storage

AbstractHigh-Arctic ecosystems are strongly affected by climate change, and it is still unclear whether they will become a carbon source or sink in the next few decades. In turn, such knowledge gaps on the drivers and the processes controlling CO2 fluxes and storage make future projections of the Arctic carbon budget a challenging goal. During summer 2019, we extensively measured CO2 fluxes at the soil–vegetation–atmosphere interface, together with basic meteoclimatic variables and ecological characteristics in the Bayelva river basin near Ny Ålesund, Spitzbergen, Svalbard (NO). By means of multi-regression models, we identified the main small-scale drivers of CO2 emission (Ecosystem Respiration, ER), and uptake (Gross Primary Production, GPP) in this tundra biome, showing that (i) at point scale, the temporal variability of fluxes is controlled by the classical drivers, i.e. air temperature and solar irradiance respectively for ER and GPP, (ii) at site scale, the heterogeneity of fractional vegetation cover, soil moisture and vegetation type acted as additional source of variability for both CO2 emissions and uptake. The assessment of the relative importance of such drivers in the multi-regression model contributes to a better understanding of the terrestrial carbon dioxide exchanges and of Critical Zone processes in the Arctic tundra.

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