Near-bottom water warming in the Laptev Sea in response to atmospheric and sea-ice conditions in 2007

Hölemann, Jens; Kirillov, Sergey; Klagge, Torben; Novikhin, Andrey; Kassens, Heidemarie; Timokhov, Leonid

doi:10.3402/polar.v30i0.6425

Cited by 43 publications

(38 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…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%

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

et al. 2017

View full text Add to dashboard Cite

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.

show abstract

Section: Permafrost Degradationmentioning

confidence: 98%

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

et al. 2017

View full text Add to dashboard Cite

show abstract

“…1). The sampling frequency of the device is 30 minutes with a beam width (footprint) of 5 m. An in-depth description of the mooring design and ADCP processing is given in Hoelemann et al (2011) and Janout et al (2012). In prior comparisons, the monthly mean ice drift was calculated from the ADCP data, and Ifremer drift data was interpolated to the mooring position.…”

Section: Accuracy Of Sea Ice Drift Datamentioning

confidence: 99%

Variability and trends in Laptev Sea ice outflow between 1992–2011

et al. 2013

View full text Add to dashboard Cite

Abstract. Variability and trends in seasonal and interannual ice area export out of the Laptev Sea between 1992 and 2011 are investigated using satellite-based sea ice drift and concentration data. We found an average total winter (October to May) ice area transport across the northern and eastern Laptev Sea boundaries (NB and EB) of 3.48 × 10 5 km 2 . The average transport across the NB (2.87 × 10 5 km 2 ) is thereby higher than across the EB (0.61 × 10 5 km 2 ), with a less pronounced seasonal cycle. The total Laptev Sea ice area flux significantly increased over the last decades (0.85 × 10 5 km 2 decade −1 , p > 0.95), dominated by increasing export through the EB (0.55 × 10 5 km 2 decade −1 , p > 0.90), while the increase in export across the NB is smaller (0.3 × 10 5 km 2 decade −1 ) and statistically not significant. The strong coupling between across-boundary SLP gradient and ice drift velocity indicates that monthly variations in ice area flux are primarily controlled by changes in geostrophic wind velocities, although the Laptev Sea ice circulation shows no clear relationship with large-scale atmospheric indices. Also there is no evidence of increasing wind velocities that could explain the overall positive trends in ice export. The increased transport rates are rather the consequence of a changing ice cover such as thinning and/or a decrease in concentration. The use of a back-propagation method revealed that most of the ice that is incorporated into the Transpolar Drift is formed during freeze-up and originates from the central and western part of the Laptev Sea, while the exchange with the East Siberian Sea is dominated by ice coming from the central and southeastern Laptev Sea. Furthermore, our results imply that years of high ice export in late winter (February to May) have a thinning effect on the ice cover, which in turn preconditions the occurence of negative sea ice extent anomalies in summer.

show abstract

“…This fact, together with the key role that seabed plays for benthic communities and in biogeochemical processes, highlights the importance of conducting complex monitoring studies. Broad environmental data collection near the seabed is not common, with only a few recent examples, such as Glover et al (2010) from Fram Strait and Hoelemann et al (2011) from Laptev Sea, both of which present a marked increase in near-bottom temperatures over last years.…”

Section: Introductionmentioning

confidence: 99%

From the worm’s point of view. I: Environmental settings of benthic ecosystems in Arctic fjord (Hornsund, Spitsbergen)

et al. 2016

View full text Add to dashboard Cite

As a consequence of ongoing climate warming, nearly all tidal glaciers in Arctic are retreating; hence, the seascape of glacial fjords is changing in many aspects. We took the example of Hornsund, the well-studied Svalbard fjord, with over 30 years of almost continuous observations of marine system. Recent data were collected during summer oceanographic surveys between 2001 and 2013 and compared with archival data from 1980s. As most of the phenomena connected with the warming happen at the sea surface (ice, wind, waves, surface currents, brackish water), we were interested, how the presumably stable, near-bottom waters in fjords behave, what are the environmental changes that are experienced directly by the worms living in the sediment. We have found that both the inner fjord basins (usually regarded as stable) and the outer fjord parts (exposed to the direct influence of shelf waters) has changed. Warming was documented in the inner basins, while cooling and warming episodes were recorded in the outer parts of the fjord. We demonstrate that following the increase melting and retreat of the glaciers, the area of shallows increased, salinity decreased and temperature increased-partly due to the advection of Atlantic waters from the shelf. Observed changes are in accordance with the model of arctic fjords evolution towards boreal ones associated with increased organic matter turnover. The observed changes are most likely typical for all cold water, glaciated fjords that are exposed to climate warming.

show abstract

Near-bottom water warming in the Laptev Sea in response to atmospheric and sea-ice conditions in 2007

Cited by 43 publications

References 24 publications

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

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

Variability and trends in Laptev Sea ice outflow between 1992–2011

From the worm’s point of view. I: Environmental settings of benthic ecosystems in Arctic fjord (Hornsund, Spitsbergen)

Contact Info

Product

Resources

About