Modeling sub-sea permafrost in the East Siberian Arctic Shelf: the Dmitry Laptev Strait

Nicolsky, Dmitry; Shakhova, Natalia

doi:10.1088/1748-9326/5/1/015006

Cited by 56 publications

(71 citation statements)

References 20 publications

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“…Thus, water heating leads to additional increasing pCO 2 in the surface water. We also suggest that progression of sub-sea permafrost thawing and decrease in ice extent could result in a significant increase in carbon discharge from the sea floor (Nicolsky and Shakhova, 2010;Shakhova et al, 2014Shakhova et al, , 2015Shakhova et al, , 2017Vonk et al, 2014) producing additional CO 2 .…”

Section: The Laptev Seamentioning

confidence: 85%

The spatial and interannual dynamics of the surface water carbonate system and air–sea CO<sub>2</sub> fluxes in the outer shelf and slope of the Eurasian Arctic Ocean

et al. 2017

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Abstract. The Arctic is undergoing dramatic changes which cover the entire range of natural processes, from extreme increases in the temperatures of air, soil, and water, to changes in the cryosphere, the biodiversity of Arctic waters, and land vegetation. Small changes in the largest marine carbon pool, the dissolved inorganic carbon pool, can have a profound impact on the carbon dioxide (CO 2 ) flux between the ocean and the atmosphere, and the feedback of this flux to climate. Knowledge of relevant processes in the Arctic seas improves the evaluation and projection of carbon cycle dynamics under current conditions of rapid climate change.Investigation of the CO 2 system in the outer shelf and continental slope waters of the Eurasian Arctic seas (the Barents, Kara, Laptev, and East Siberian seas) during 2006, 2007, and 2009 revealed a general trend in the surface water partial pressure of CO 2 (pCO 2 ) distribution, which manifested as an increase in pCO 2 values eastward. The existence of this trend was defined by different oceanographic and biogeochemical regimes in the western and eastern parts of the study area; the trend is likely increasing due to a combination of factors determined by contemporary change in the Arctic climate, each change in turn evoking a series of synergistic effects. A high-resolution in situ investigation of the carbonate system parameters of the four Arctic seas was carried out in the warm season of 2007; this year was characterized by the next-to-lowest historic sea-ice extent in the Arctic Ocean, on satellite record, to that date. The study showed the different responses of the seawater carbonate system to the environment changes in the western vs. the eastern Eurasian Arctic seas. The large, open, highly productive water area in the northern Barents Sea enhances atmospheric CO 2 uptake. In contrast, the uptake of CO 2 was strongly weakened in the outer shelf and slope waters of the East Siberian Arctic seas under the 2007 environmental conditions. The surface seawater appears in equilibrium or slightly supersaturated by CO 2 relative to atmosphere because of the increasing influence of river runoff and its input of terrestrial organic matter that mineralizes, in combination with the high surface water temperature during sea-ice-free conditions. This investigation shows the importance of processes that vary on small scales, both in time and space, for estimating the air-sea exchange of CO 2 . It stresses the need for highresolution coverage of ocean observations as well as time series. Furthermore, time series must include multi-year studies in the dynamic regions of the Arctic Ocean during these times of environmental change.

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Section: The Laptev Seamentioning

confidence: 85%

The spatial and interannual dynamics of the surface water carbonate system and air–sea CO<sub>2</sub> fluxes in the outer shelf and slope of the Eurasian Arctic Ocean

et al. 2017

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“…Riverine input to the Laptev Sea also supports the formation and growth of subsea thaw lakes and taliks, which are effective gas migration pathways to the seabed (Hölemann et al, 2011;Nicolsky and Shakhova, 2010;Shakhova and Semiletov, 2007;Shakhova et al, 2014).…”

Section: Permafrost Degradationmentioning

confidence: 98%

“…Heat flow in rift zones also provides geologic control (Drachev et al, 2003;Nicolsky et al, 2012). High heat flow areas include relic thaw lakes and river valleys that were submerged during the Holocene inundation.…”

Section: Permafrost Degradationmentioning

confidence: 99%

“…High heat flow areas include relic thaw lakes and river valleys that were submerged during the Holocene inundation. These still drive modern permafrost degradation (Nicolsky and Shakhova, 2010;Nicolsky et al, 2012;Shakhova and Semiletov, 2009).…”

Section: Permafrost Degradationmentioning

confidence: 99%

“…The outer Laptev Sea is one of the few places where active oceanic spreading approaches a continental margin (Drachev et al, 2003) and correlates with the "hot" area crossed by the Ust' Lensky Rift and KhatangaLomonosov Fracture (Drachev et al, 2003;Nicolsky et al, 2012). Evidence of rifting is provided by hydrothermal fauna remnants documented around grabens (dropped blocks between faults) in the up-slope area that typically occurs along oceanic divergent axes (Drachev et al, 2003).…”

Section: Permafrost Degradationmentioning

confidence: 99%

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Sonar gas flux estimation by bubble insonification: application to methane bubble flux from seep areas in the outer Laptev Sea

et al. 2017

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Abstract. Sonar surveys provide an effective mechanism for mapping seabed methane flux emissions, with Arctic submerged permafrost seepage having great potential to significantly affect climate. We created in situ engineered bubble plumes from 40 m depth with fluxes spanning 0.019 to 1.1 L s −1 to derive the in situ calibration curve (Q(σ )). These nonlinear curves related flux (Q) to sonar return (σ ) for a multibeam echosounder (MBES) and a single-beam echosounder (SBES) for a range of depths. The analysis demonstrated significant multiple bubble acoustic scattering -precluding the use of a theoretical approach to derive Q(σ ) from the product of the bubble σ (r) and the bubble size distribution where r is bubble radius. The bubble plume σ occurrence probability distribution function ( (σ )) with respect to Q found (σ ) for weak σ well described by a power law that likely correlated with small-bubble dispersion and was strongly depth dependent. (σ ) for strong σ was largely depth independent, consistent with bubble plume behavior where large bubbles in a plume remain in a focused core.(σ ) was bimodal for all but the weakest plumes. Q(σ ) was applied to sonar observations of natural arctic Laptev Sea seepage after accounting for volumetric change with numerical bubble plume simulations. Simulations addressed different depths and gases between calibration and seep plumes. Total mass fluxes (Q m ) were 5.56, 42.73, and 4.88 mmol s −1 for MBES data with good to reasonable agreement (4-37 %) between the SBES and MBES systems. The seepage flux occurrence probability distribution function ( (Q)) was bimodal, with weak (Q) in each seep area well described by a power law, suggesting primarily minor bubble plumes. The seepage-mapped spatial patterns suggested subsurface geologic control attributing methane fluxes to the current state of subsea permafrost.

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Numerical model of the geothermal regime on the Beaufort Shelf, arctic Canada since the Last Interglacial

Taylor

Dallimore

Hill

et al. 2013

J. Geophys. Res. Earth Surf.

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[1] A finite element geothermal model is developed for the outer Mackenzie Delta-Beaufort Sea shelf to predict permafrost evolution since the Last Interglacial~130-116 kaBP(cal). The purpose is to reconcile sparse observations of the depth and extent of ice-bonded permafrost with sediment properties and the paleoenvironment. Sea level curves determine, as a function of time, areas of the shelf that were subaerially exposed, promoting permafrost aggradation, and areas that were submerged, promoting permafrost degradation. Assuming as a model starting point that a paleoclimate similar to today persisted through the Last Interglacial, permafrost subsequently aggrades in depth and advances seaward from the present shoreline to the shelf/slope bathymetric break by the Last Glacial Maximum (LGM)~26 kaBP(cal). Modeled permafrost exhibits reduced growth in depth and seaward progression that correlate with early and middle Wisconsin stillstands in sea level. Following the LGM and rise in sea level, offshore permafrost degrades and permafrost base rises~100 m to its present depth of 600 m. The offshore limit of modeled ice-bonded permafrost lies at the~95 m isobath, within 1 km of the bathymetric shelf/slope break. The model replicates features of offshore permafrost body observed seismically and demonstrates that warm outflow from the Mackenzie River depresses the upper surface of offshore permafrost by tens of meters to the 20 m isobath. Although Pleistocene permafrost predated the Wisconsinan, the model demonstrates that the paleoenvironment of the last 125,000 years is sufficient to develop the depth, seaward extent, and principal features of the permafrost body.

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Modeling sub-sea permafrost in the East Siberian Arctic Shelf: the Dmitry Laptev Strait

Cited by 56 publications

References 20 publications

The spatial and interannual dynamics of the surface water carbonate system and air–sea CO<sub>2</sub> fluxes in the outer shelf and slope of the Eurasian Arctic Ocean

The spatial and interannual dynamics of the surface water carbonate system and air–sea CO<sub>2</sub> fluxes in the outer shelf and slope of the Eurasian Arctic Ocean

Sonar gas flux estimation by bubble insonification: application to methane bubble flux from seep areas in the outer Laptev Sea

Numerical model of the geothermal regime on the Beaufort Shelf, arctic Canada since the Last Interglacial

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Modeling sub-sea permafrost in the East Siberian Arctic Shelf: the Dmitry Laptev Strait

Cited by 56 publications

References 20 publications

The spatial and interannual dynamics of the surface water carbonate system and air–sea CO&lt;sub&gt;2&lt;/sub&gt; fluxes in the outer shelf and slope of the Eurasian Arctic Ocean

The spatial and interannual dynamics of the surface water carbonate system and air–sea CO&lt;sub&gt;2&lt;/sub&gt; fluxes in the outer shelf and slope of the Eurasian Arctic Ocean

Sonar gas flux estimation by bubble insonification: application to methane bubble flux from seep areas in the outer Laptev Sea

Numerical model of the geothermal regime on the Beaufort Shelf, arctic Canada since the Last Interglacial

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Product

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The spatial and interannual dynamics of the surface water carbonate system and air–sea CO<sub>2</sub> fluxes in the outer shelf and slope of the Eurasian Arctic Ocean

The spatial and interannual dynamics of the surface water carbonate system and air–sea CO<sub>2</sub> fluxes in the outer shelf and slope of the Eurasian Arctic Ocean