The Roles of Thermokarst Lakes in Thawing Permafrost Zones: Ecological Response

2021 ◽  
Author(s):  
D. Vural ◽  
E.V. Yavuz
Keyword(s):  
Thermokarst Lakes ◽  
Ecological Response ◽  
Thawing Permafrost

scholarly journals Geographic and seasonal variation of dissolved methane and aerobic methane oxidation in Alaskan lakes

2015 ◽  
Vol 12 (15) ◽  
pp. 4595-4606 ◽  
Author(s):  
K. Martinez-Cruz ◽  
A. Sepulveda-Jauregui ◽  
K. Walter Anthony ◽  
F. Thalasso
Keyword(s):  
Organic Carbon ◽  
Ch4 Oxidation ◽  
Geographic Variations ◽  
Large Variability ◽  
Thermokarst Lakes ◽  
Oxidation Rates ◽  
Key Factor ◽  
Thawing Permafrost ◽  
Surrounding Landscape ◽  
Dissolved O2

Abstract. Methanotrophic bacteria play an important role oxidizing a significant fraction of methane (CH4) produced in lakes. Aerobic CH4 oxidation depends mainly on lake CH4 and oxygen (O2) concentrations, in such a manner that higher MO rates are usually found at the oxic/anoxic interface, where both molecules are present. MO also depends on temperature, and via methanogenesis, on organic carbon input to lakes, including from thawing permafrost in thermokarst (thaw)-affected lakes. Given the large variability in these environmental factors, CH4 oxidation is expected to be subject to large seasonal and geographic variations, which have been scarcely reported in the literature. In the present study, we measured CH4 oxidation rates in 30 Alaskan lakes along a north-south latitudinal transect during winter and summer with a new field laser spectroscopy method. Additionally, we measured dissolved CH4 and O2 concentrations. We found that in the winter, aerobic CH4 oxidation was mainly controlled by the dissolved O2 concentration, while in the summer it was controlled primarily by the CH4 concentration, which was scarce compared to dissolved O2. The permafrost environment of the lakes was identified as another key factor. Thermokarst (thaw) lakes formed in yedoma-type permafrost had significantly higher CH4 oxidation rates compared to other thermokarst and non-thermokarst lakes formed in non-yedoma permafrost environments. As thermokarst lakes formed in yedoma-type permafrost have been identified to receive large quantities of terrestrial organic carbon from thaw and subsidence of the surrounding landscape into the lake, confirming the strong coupling between terrestrial and aquatic habitats and its influence on CH4 cycling.

Focus on Thermokarst Lakes in Indian Himalaya: Inception and Implication under Warming Climate

2020 ◽  
Vol 6 (2) ◽  
pp. 59-69
Author(s):  
Pratima Pandey ◽  
S. Nawaz Ali ◽  
Vikram Sharma ◽  
Prashant K. Champati Ray
Keyword(s):  
Western Himalaya ◽  
High Mountain ◽  
Thermokarst Lakes ◽  
Glacial Environments ◽  
Global Warming Scenario ◽  
Scientific Attention ◽  
Topographic Depressions ◽  
Permafrost Thawing ◽  
The Impact ◽  
Thaw Lakes

Thermokarst (Thaw) lakes are landforms found in topographic depressions created by thawing ground ice in permafrost zones. They play an important role in the regulation of climatic functions. These lakes are a manifestation of warming surface temperatures that accelerates the ice-rich permafrost to degrade by creating marshy hollows/ponds. In the current global warming scenario, the thermokarst lakes in the high mountain regions (Himalaya) are expected to grow further. This accelerate permafrost thawing which will affect the carbon cycle, hydrology and local ecosystems. This phenomenon has attracted huge scientific attention because it has led to a rapid mass change of glaciers in the region, including extensive changes occurring on peri-glacial environments. The most striking fact is the release of an enormous amount of greenhouse gases, including methane, carbon dioxide and nitrous oxide that is locked in these lakes. The present study delves into the thermokarst lakes in the upper reaches of Chandra Valley and Western Himalaya. The study also aims at designating the impact of their changes on the ecosystem, particularly their influence on the atmospheric greenhouse gas concentrations.

Diatoms in bottom sediments of thermokarst lakes of the Pechora Delta

2019 ◽  
pp. 285-290
Author(s):  
Elvira A. Zinnatova, Larisa A. Frolova ◽  
Larisa A. Frolova
Keyword(s):  
Bottom Sediments ◽  
Environmental Conditions ◽  
Sources Of Information ◽  
Thermokarst Lakes ◽  
Thermokarst Lake ◽  
Fouling Organisms ◽  
Diatom Complexes

The Northern lakes are good objects for paleoclimatic reconstructions. One of the sources of information about changes in the ecosystems of lakes are diatoms. The study of diatom complexes revealed 133 taxa belonging to 49 genera, 24 families, 13 orders and 3 classes in the bottom sediments of the thermokarst lake of the Pechora Delta. Dominated by the Holarctic representatives of benthic and fouling organisms giving preference to the alkaline environmental conditions.

Biogeochemistry of macrophytes, sediments and porewaters in thermokarst lakes of permafrost peatlands, western Siberia

2021 ◽  
Vol 763 ◽  
pp. 144201
Author(s):  
Rinat M. Manasypov ◽  
Oleg S. Pokrovsky ◽  
Liudmila S. Shirokova ◽  
Yves Auda ◽  
Nadezhda S. Zinner ◽  
...  
Keyword(s):  
Western Siberia ◽  
Thermokarst Lakes

scholarly journals Aged soils contribute little to contemporary carbon cycling downstream of thawing permafrost peatlands

2021 ◽  
Author(s):  
Andrew J Tanentzap ◽  
Katheryn Burd ◽  
McKenzie Kuhn ◽  
Cristian Estop‐Aragonés ◽  
Suzanne E. Tank ◽  
...  
Keyword(s):  
Carbon Cycling ◽  
Thawing Permafrost

scholarly journals Thawing Permafrost in Arctic Coastal Communities: A Framework for Studying Risks from Climate Change

2021 ◽  
Vol 13 (5) ◽  
pp. 2651
Author(s):  
Joan Nymand Larsen ◽  
Peter Schweitzer ◽  
Khaled Abass ◽  
Natalia Doloisio ◽  
Susanna Gartler ◽  
...  
Keyword(s):  
Risk Management ◽  
Risk Perception ◽  
Stakeholder Involvement ◽  
Coastal Communities ◽  
Mitigation Strategies ◽  
Socially Constructed ◽  
Local Stakeholders ◽  
Risk Framework ◽  
Relevant Stakeholder ◽  
Thawing Permafrost

Thawing permafrost creates risks to the environment, economy and culture in Arctic coastal communities. Identification of these risks and the inclusion of the societal context and the relevant stakeholder involvement is crucial in risk management and for future sustainability, yet the dual dimensions of risk and risk perception is often ignored in conceptual risk frameworks. In this paper we present a risk framework for Arctic coastal communities. Our framework builds on the notion of the dual dimensions of risk, as both physically and socially constructed, and it places risk perception and the coproduction of risk management with local stakeholders as central components into the model. Central to our framework is the importance of multidisciplinary collaboration. A conceptual model and processual framework with a description of successive steps is developed to facilitate the identification of risks of thawing permafrost in a collaboration between local communities and scientists. Our conceptual framework motivates coproduction of risk management with locals in the identification of these risks from permafrost thaw and the development of adaptation and mitigation strategies.

The ecological response of insectivorous bats to coastal lagoon degradation

2016 ◽  
Vol 202 ◽  
pp. 10-19 ◽  
Author(s):  
Bradley K. Clarke-Wood ◽  
Kim M. Jenkins ◽  
Brad S. Law ◽  
Rachel V. Blakey
Keyword(s):  
Coastal Lagoon ◽  
Insectivorous Bats ◽  
Ecological Response

scholarly journals Diploptene <i>δ</i><sup>13</sup>C values from contemporary thermokarst lake sediments show complex spatial variation

2016 ◽  
Vol 13 (8) ◽  
pp. 2611-2621 ◽  
Author(s):  
Kimberley L. Davies ◽  
Richard D. Pancost ◽  
Mary E. Edwards ◽  
Katey M. Walter Anthony ◽  
Peter G. Langdon ◽  
...  
Keyword(s):  
Spatial Variation ◽  
Lake Sediments ◽  
Methane Oxidation ◽  
Methane Production ◽  
Small Scale ◽  
Δ13c Values ◽  
Thermokarst Lakes ◽  
Methane Ebullition ◽  
Methane Efflux ◽  
Isotopic Signal

Abstract. Cryospheric changes in northern high latitudes are linked to significant greenhouse gas flux to the atmosphere, for example, methane that originates from organic matter decomposition in thermokarst lakes. The set of pathways that link methane production in sediments, via oxidation in the lake system, to the flux of residual methane to the atmosphere is complex and exhibits temporal and spatial variation. The isotopic signal of bacterial biomarkers (hopanoids, e.g. diploptene) in sediments has been used to identify contemporary ocean-floor methane seeps and, in the geological record, periods of enhanced methane production (e.g. the PETM). The biomarker approach could potentially be used to assess temporal changes in lake emissions through the Holocene via the sedimentary biomarker record. However, there are no data on the consistency of the signal of isotopic depletion in relation to source or on the amount of noise (unexplained variation) in biomarker values from modern lake sediments. We assessed methane oxidation as represented by the isotopic signal of biomarkers from methane oxidising bacteria (MOB) in multiple surface sediment samples in three distinct areas known to emit varying levels of methane in two shallow Alaskan thermokarst lakes. Diploptene was present and had δ13C values lower than −38 ‰ in all sediments analysed, suggesting methane oxidation was widespread. However, there was considerable variation in δ13C values within each area. The most 13C-depleted diploptene was found in an area of high methane ebullition in Ace Lake (diploptene δ13C values between −68.2 and −50.1 ‰). In contrast, significantly higher diploptene δ13C values (between −42.9 and −38.8 ‰) were found in an area of methane ebullition in Smith Lake. δ13C values of diploptene between −56.8 and −46.9 ‰ were found in the centre of Smith Lake, where ebullition rates are low but diffusive methane efflux occurs. The small-scale heterogeneity of the samples may reflect patchy distribution of substrate and/or MOB within the sediments. The two ebullition areas differ in age and type of organic carbon substrate, which may affect methane production, transport, and subsequent oxidation. Given the high amount of variation in surface samples, a more extensive calibration of modern sediment properties, within and among lakes, is required before down-core records of hopanoid isotopic signatures are developed.

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