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 Spatial and temporal patterns of biophysical variables and their influence on CO2 flux in a high arctic wetland

2021 ◽  
Author(s):  
Sarah Luce
Keyword(s):  
Climate Change ◽  
Carbon Sources ◽  
Co2 Flux ◽  
High Arctic ◽  
Co2 Exchange ◽  
Co2 Production ◽  
Co2 Uptake ◽  
Spatial And Temporal Patterns ◽  
Carbon Cycles ◽  
Arctic Wetlands

Arctic wetlands have been globally important carbon reservoirs throughout the past but climate change is threatening to shift their status to carbon sources. Increasing Arctic temperatures are depleting perennial snowpacks these wetlands depend upon as their hydrological inputs which is altering their environmental conditions and carbon cycles. The objective of this study is to investigate how the physical conditions of Arctic wetlands will be altered by climate change and what influence these changes will have on CO2 exchange. High spatial and temporal resolution biophysical data from a high Arctic wetland, collected over the growing season of 2015, was used for this analysis. The results from this study indicate that the wetland is at risk of thawing and drying out under a warmer climate regime. CO2 emissions were found to increase most significantly with increased air temperatures, while CO2 uptake increased with increases in solar radiation and soil moisture. Combined, these results suggest that CO2 production in the soil will increase while CO2 uptake will decrease in Arctic wetlands as climate change continues.

scholarly journals Stability of Ecosystem CO2 Flux in Response to Changes in Precipitation in a Semiarid Grassland

2019 ◽  
Vol 11 (9) ◽  
pp. 2597 ◽  
Author(s):  
Kaiqiang Bao ◽  
Haifeng Tian ◽  
Min Su ◽  
Liping Qiu ◽  
Xiaorong Wei ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Soil Temperature ◽  
Ecosystem Respiration ◽  
Co2 Flux ◽  
Co2 Exchange ◽  
Semiarid Grassland ◽  
Considerable Uncertainty ◽  
C Cycling ◽  
Precipitation Regimes ◽  
Carbon Dioxide Co2

Carbon dioxide (CO2) flux provides feedback between C cycling and the climatic system. There is considerable uncertainty regarding the direction and magnitude of the responses of this process to precipitation changes, hindering accurate prediction of C cycling in a changing world. We examined the responses of ecosystem CO2 flux to ambient precipitation and experimentally decreased (−35%) and increased precipitation (+20%) in a semiarid grassland in China between July 2013 and September 2015. The measured CO2 flux components included the gross ecosystem productivity (GEP), net ecosystem CO2 exchange (NEE), ecosystem respiration (Re), and soil respiration (Rs). The results showed that the seasonal and diurnal patterns of most components of ecosystem CO2 flux were minimally affected by precipitation treatments, with less than 4% changes averaged across the three growing seasons. GEP and NEE had a quadratic relationship, while Re and Rs increased exponentially with soil temperature. GEP, RE, and Rs, however, decreased with soil moisture. Decreased precipitation reduced the dependence of CO2 flux on soil temperature but partly increased the dependence on soil moisture; in contrast, increased precipitation had the opposite influence. Our results suggested a relatively stable CO2 flux in this semiarid grassland across the tested precipitation regimes.

scholarly journals Spatial and temporal patterns of biophysical variables and their influence on CO2 flux in a high arctic wetland

2021 ◽  
Author(s):  
Sarah Luce
Keyword(s):  
Climate Change ◽  
Carbon Sources ◽  
Co2 Flux ◽  
High Arctic ◽  
Co2 Exchange ◽  
Co2 Production ◽  
Co2 Uptake ◽  
Spatial And Temporal Patterns ◽  
Carbon Cycles ◽  
Arctic Wetlands

Arctic wetlands have been globally important carbon reservoirs throughout the past but climate change is threatening to shift their status to carbon sources. Increasing Arctic temperatures are depleting perennial snowpacks these wetlands depend upon as their hydrological inputs which is altering their environmental conditions and carbon cycles. The objective of this study is to investigate how the physical conditions of Arctic wetlands will be altered by climate change and what influence these changes will have on CO2 exchange. High spatial and temporal resolution biophysical data from a high Arctic wetland, collected over the growing season of 2015, was used for this analysis. The results from this study indicate that the wetland is at risk of thawing and drying out under a warmer climate regime. CO2 emissions were found to increase most significantly with increased air temperatures, while CO2 uptake increased with increases in solar radiation and soil moisture. Combined, these results suggest that CO2 production in the soil will increase while CO2 uptake will decrease in Arctic wetlands as climate change continues.

Effects of Permafrost Disturbance on Trace Gas Flux in a High Arctic Ecosystem

2016 ◽  
Author(s):  
Alison Beamish
Keyword(s):  
Active Layer ◽  
Global Climate ◽  
High Arctic ◽  
Co2 Exchange ◽  
The Arctic ◽  
Trace Gas ◽  
Arctic Ecosystems ◽  
Gas Flux ◽  
Temperature And Precipitation ◽  
The Impact

High Arctic ecosystems are likely to experience some of the earliest and most extreme changes in climate as a result of future global climate change. These changes will likely include both increases in temperature and precipitation. High-Arctic ecosystems are very sensitive to climatic disruption, and the response of these ecosystems to changes in climate could have a strong influence on future climate. In particular, changes in temperature and moisture will cause the active layer to deepen as a result of enhanced permafrost melting. This deepening will decrease stability in shallow slopes leading to soil disturbances known as active layer detachments.. We are exploring the impact of active layer detachments on net ecosystem trace gas (CH4, N2O and CO2) exchange at the Cape Bounty Arctic Watershed Observatory on Melville Island. Eight plots were established in four different detachments, covering a range of disturbance intensities (control, disturbed and highly disturbed). Based on collected and analysed gas samples, it appears disturbance has an effect on trace gas exchange. Initial results show a distinct difference across the disturbance gradient. These findings have important implications if summer temperatures are to rise and disturbance frequency increases. Continued monitoring of these sites is important to assess the changes in trace gas flux over time since disturbance. Quantifying the impact of active layer detachments is crucial to furthering our understanding of the arctic carbon and trace gas cycles.

scholarly journals Constraint of soil moisture on CO<sub>2</sub> efflux from tundra lichen, moss, and tussock in Council, Alaska, using a hierarchical Bayesian model

2014 ◽  
Vol 11 (19) ◽  
pp. 5567-5579 ◽  
Author(s):  
Y. Kim ◽  
K. Nishina ◽  
N. Chae ◽  
S. J. Park ◽  
Y. J. Yoon ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Environmental Factors ◽  
Soil Temperature ◽  
Co2 Emission ◽  
Emission Rate ◽  
Growing Season ◽  
The Arctic ◽  
Co2 Efflux ◽  
Growing Seasons ◽  
Tundra Ecosystem

Abstract. The tundra ecosystem is quite vulnerable to drastic climate change in the Arctic, and the quantification of carbon dynamics is of significant importance regarding thawing permafrost, changes to the snow-covered period and snow and shrub community extent, and the decline of sea ice in the Arctic. Here, CO2 efflux measurements using a manual chamber system within a 40 m × 40 m (5 m interval; 81 total points) plot were conducted within dominant tundra vegetation on the Seward Peninsula of Alaska, during the growing seasons of 2011 and 2012, for the assessment of driving parameters of CO2 efflux. We applied a hierarchical Bayesian (HB) model – a function of soil temperature, soil moisture, vegetation type, and thaw depth – to quantify the effects of environmental factors on CO2 efflux and to estimate growing season CO2 emissions. Our results showed that average CO2 efflux in 2011 was 1.4 times higher than in 2012, resulting from the distinct difference in soil moisture between the 2 years. Tussock-dominated CO2 efflux is 1.4 to 2.3 times higher than those measured in lichen and moss communities, revealing tussock as a significant CO2 source in the Arctic, with a wide area distribution on the circumpolar scale. CO2 efflux followed soil temperature nearly exponentially from both the observed data and the posterior medians of the HB model. This reveals that soil temperature regulates the seasonal variation of CO2 efflux and that soil moisture contributes to the interannual variation of CO2 efflux for the two growing seasons in question. Obvious changes in soil moisture during the growing seasons of 2011 and 2012 resulted in an explicit difference between CO2 effluxes – 742 and 539 g CO2 m−2 period−1 for 2011 and 2012, respectively, suggesting the 2012 CO2 emission rate was reduced to 27% (95% credible interval: 17–36%) of the 2011 emission, due to higher soil moisture from severe rain. The estimated growing season CO2 emission rate ranged from 0.86 Mg CO2 in 2012 to 1.20 Mg CO2 in 2011 within a 40 m × 40 m plot, corresponding to 86 and 80% of annual CO2 emission rates within the western Alaska tundra ecosystem, estimated from the temperature dependence of CO2 efflux. Therefore, this HB model can be readily applied to observed CO2 efflux, as it demands only four environmental factors and can also be effective for quantitatively assessing the driving parameters of CO2 efflux.

CO2 exchange in three Canadian High Arctic ecosystems: response to long-term experimental warming

2004 ◽  
Vol 10 (12) ◽  
pp. 1981-1995 ◽  
Author(s):  
Jeffrey M. Welker ◽  
Jace T. Fahnestock ◽  
Greg H. R. Henry ◽  
Kevin W. O'Dea ◽  
Rodney A. Chimner
Keyword(s):  
High Arctic ◽  
Co2 Exchange ◽  
Experimental Warming ◽  
Arctic Ecosystems ◽  
Canadian High Arctic

scholarly journals Do Nitrogen Concentration and Forage Quality of the MossRacomitrium lanuginosumIncrease with Latitude?

2009 ◽  
Vol 2009 ◽  
pp. 1-4 ◽  
Author(s):  
J. D. M. Speed ◽  
R. van der Wal ◽  
S. J. Woodin
Keyword(s):  
Plant Biomass ◽  
Nitrogen Concentration ◽  
Forage Quality ◽  
N Deposition ◽  
The Arctic ◽  
Substantial Part ◽  
Arctic Ecosystems ◽  
Arctic Regions ◽  
Herbivore Species

Mosses are an important component of high latitude ecosystems, contributing the majority of the plant biomass in many communities. In Arctic regions mosses also form a substantial part of the diet of many herbivore species. This may reflect either the availability of moss or its quality as forage. Here we test whether the nitrogen concentration and forage quality of the mossRacomitrium lanuginosumincrease with latitude and discuss the findings with reference to herbivore utilisation of moss in the Arctic. In contrast to vascular plants, moss nitrogen concentration significantly decreased with latitude (P<.01), in line with estimates of N deposition at the sampling sites. In addition, no evidence of an increase in nutritional quality of moss with latitude was observed; thus, this study suggests that the utilisation of moss by herbivores in arctic ecosystems maybe a function of their relatively high biomass rather than their quality as forage.

Effect of soil temperature and soil moisture on CO2 flux from eroded landscape positions on black soil in Northeast China

2014 ◽  
Vol 144 ◽  
pp. 119-125 ◽  
Author(s):  
Shoucai Wei ◽  
Xiaoping Zhang ◽  
Neil B. McLaughlin ◽  
Aizhen Liang ◽  
Shuxia Jia ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Soil Temperature ◽  
Northeast China ◽  
Co2 Flux ◽  
Black Soil

scholarly journals Does soil moisture overrule temperature dependency of soil respiration in Mediterranean riparian forests?

2014 ◽  
Vol 11 (6) ◽  
pp. 7991-8022 ◽  
Author(s):  
C.-T. Chang ◽  
S. Sabaté ◽  
D. Sperlich ◽  
S. Poblador ◽  
F. Sabater ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Soil Respiration ◽  
Soil Temperature ◽  
Groundwater Level ◽  
Tree Species ◽  
Riparian Forest ◽  
Co2 Flux ◽  
Control Factor ◽  
Primary Control ◽  
Heterotrophic Soil Respiration

Abstract. Soil respiration (SR) is a major component of ecosystem's carbon cycle and represents the second largest CO2 flux of the terrestrial biosphere. Soil temperature is considered to be the primary control on SR whereas soil moisture as the secondary control factor. However, soil moisture can become the dominant control on SR in very wet or dry conditions. Determining the trigger that switches-on soil moisture as the primary control factor of SR will provide a deeper understanding on how SR changes under projected future increased droughts. Specific objectives of this study were (1) to investigate the seasonal variations and the relationship between SR and both soil temperature and moisture in a Mediterranean riparian forest along a groundwater level gradient; (2) to determine soil moisture thresholds at which SR is rather controlled by soil moisture than by temperature; (3) to compare SR responses under different tree species present in a Mediterranean riparian forest (Alnus, glutinosa, Populus nigra and Fraxinus excelsior). Results showed that the heterotrophic soil respiration rate, groundwater level and 30 cm integral soil moisture (SM30) decreased significantly from riverside to uphill and showed a pronounced seasonality. SR rates showed significant differences among tree species, with higher SR for P. nigra and lower SR for A. glutinosa. The lower threshold of soil moisture was 20 and 17% for heterotrophic and total SR respectively. Daily mean SR rate was positively correlated with soil temperature when soil moisture exceeded the threshold, with Q10 values ranging from 1.19 to 2.14; nevertheless, SR became decoupled from soil temperature when soil moisture dropped below these thresholds.

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.

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