Variability of river discharge and Atlantic-water inflow at the Laptev Sea continental margin during the past 15,000 years: implications from maceral and biomarker records

2000 ◽  
Vol 89 (3) ◽  
pp. 578-591 ◽  
Author(s):  
B. Boucsein ◽  
K. Fahl ◽  
R. Stein
Keyword(s):  
Continental Margin ◽  
River Discharge ◽  
Atlantic Water ◽  
Water Inflow ◽  
Laptev Sea ◽  
The Past ◽  
The Laptev Sea

scholarly journals Modified Halocline Water over the Laptev Sea Continental Margin: Historical Data Analysis

2012 ◽  
Vol 25 (16) ◽  
pp. 5556-5565 ◽  
Author(s):  
Igor A. Dmitrenko ◽  
Sergey A. Kirillov ◽  
Vladimir V. Ivanov ◽  
Bert Rudels ◽  
Nuno Serra ◽  
...  
Keyword(s):  
Continental Margin ◽  
North Atlantic Ocean ◽  
Source Region ◽  
Vertical Mixing ◽  
Atlantic Water ◽  
Laptev Sea ◽  
Boundary Current ◽  
Salinity Stratification ◽  
The North ◽  
The Laptev Sea

Abstract Historical hydrographic data (1940s–2010) show a distinct cross-slope difference of the lower halocline water (LHW) over the Laptev Sea continental margins. Over the slope, the LHW is on average warmer and saltier by 0.2°C and 0.5 psu, respectively, relative to the off-slope LHW. The LHW temperature time series constructed from the on-slope historical records are related to the temperature of the Atlantic Water (AW) boundary current transporting warm water from the North Atlantic Ocean. In contrast, the on-slope LHW salinity is linked to the sea ice and wind forcing over the potential upstream source region in the Barents and northern Kara Seas, as also indicated by hydrodynamic model results. Over the Laptev Sea continental margin, saltier LHW favors weaker salinity stratification that, in turn, contributes to enhanced vertical mixing with underlying AW.

scholarly journals Changes in the paleohydrological conditions in the Laptev Sea during the late Pleistocene and Holocene based on a study of aquatic palynomorphs

2019 ◽  
Vol 59 (3) ◽  
pp. 433-448
Author(s):  
T. S. Klyuvitkina ◽  
Ye. I. Polyakova
Keyword(s):  
Environmental Change ◽  
Sea Level ◽  
Continental Margin ◽  
Cold Water ◽  
Sediment Cores ◽  
Atlantic Water ◽  
Time Interval ◽  
Laptev Sea ◽  
Global Sea Level ◽  
The Laptev Sea

On the basis of aquatic palynomorph assemblages in sediment cores obtained from the eastern Laptev Sea shelf, major phases of environmental change associated with the last postglacial global sea-level rise can be recognized for the time since 17.5 calendar years BP (cal. ka). It is shown that in the time interval of 17.5–13.0 cal. ka in the western part of the sea there was a very cold-water sea basin with permanent sea-ice cover, 12.3–11.2 cal. ka the outer shelf were characterized by increased precipitation of river-loaded matter in a river-proximal environment of Anabara and Khatanga rivers, and the period of 11.2–7.0 cal ka was marked by enhanced influence of Atlantic water at the Laptev Sea continental margin. Modern-like environments were established in this part of the sea approximately 7.0 cal. ka.

scholarly journals On the biogeochemical signature of the Lena River from its headwaters to the Arctic Ocean

2011 ◽  
Vol 8 (2) ◽  
pp. 2093-2143 ◽  
Author(s):  
I. P. Semiletov ◽  
I. I. Pipko ◽  
N. E. Shakhova ◽  
O. V. Dudarev ◽  
S. P. Pugach ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Arctic Ocean ◽  
River Discharge ◽  
Total Carbon ◽  
The Arctic ◽  
Time Shift ◽  
Laptev Sea ◽  
Lena River ◽  
The Arctic Ocean ◽  
The Laptev Sea

Abstract. The Lena River integrates biogeochemical signals from its vast drainage basin and its signal reaches far out over the Arctic Ocean. Transformation of riverine organic carbon into mineral carbon, and mineral carbon into the organic form in the Lena River watershed, can be considered a quasi-equilibrated processes. Increasing the Lena discharge causes opposite effects on total organic (TOC) and inorganic (TCO2) carbon: TOC concentration increases, while TCO2 concentration decreases. Significant inter-annual variability in mean values of TCO2, TOC, and their sum (TC) has been found. This variability is determined by changes in land hydrology which cause differences in the Lena River discharge, because a negative correlation may be found between TC in September and mean discharge in August (a time shift of about one month is required for water to travel from Yakutsk to the Laptev Sea). Total carbon entering the sea with the Lena discharge is estimated to be almost 10 Tg C y−1. The annual Lena River discharge of particulate organic carbon (POC) may be equal to 0.38 Tg (moderate to high estimate). If we instead accept Lisytsin's (1994) statement concerning the precipitation of 85–95% of total particulate matter (PM) (and POC) on the marginal "filter", then only about 0.03–0.04 Tg of POC reaches the Laptev Sea from the Lena River. The Lena's POC export would then be two orders of magnitude less than the annual input of eroded terrestrial carbon onto the shelf of the Laptev and East Siberian seas, which is about 4 Tg. The Lena River is characterized by relatively high concentrations of primary greenhouse gases: CO2 and dissolved CH4. During all seasons the river is supersaturated in CO2 compared to the atmosphere: up to 1.5–2 fold in summer, and 4–5 fold in winter. This results in a narrow zone of significant CO2 supersaturation in the adjacent coastal sea. Spots of dissolved CH4 in the Lena delta channels may reach 100 nM, but the CH4 concentration decreases to 5–20 nM towards the sea, which suggests only a minor role of riverborne export of CH4 for the East Siberian Arctic Shelf (ESAS) CH4 budget in coastal waters. Instead, the seabed appears to be the source that provides most of the CH4 to the Arctic Ocean.

scholarly journals Mooring-Based Observations of Double-Diffusive Staircases over the Laptev Sea Slope*

2012 ◽  
Vol 42 (1) ◽  
pp. 95-109 ◽  
Author(s):  
Igor V. Polyakov ◽  
Andrey V. Pnyushkov ◽  
Robert Rember ◽  
Vladimir V. Ivanov ◽  
Y.-D. Lenn ◽  
...  
Keyword(s):  
Double Diffusion ◽  
Atlantic Water ◽  
Arctic Sea Ice ◽  
Heat Fluxes ◽  
Laptev Sea ◽  
Depth Range ◽  
Diffusive Convection ◽  
Arctic Sea ◽  
Effective Transfer ◽  
The Laptev Sea

Abstract A yearlong time series from mooring-based high-resolution profiles of water temperature and salinity from the Laptev Sea slope (2003–04; 2686-m depth; 78°26′N, 125°37′E) shows six remarkably persistent staircase layers in the depth range of ~140–350 m encompassing the upper Atlantic Water (AW) and lower halocline. Despite frequent displacement of isopycnal surfaces by internal waves and eddies and two strong AW warming pulses that passed through the mooring location in February and late August 2004, the layers preserved their properties. Using laboratory-derived flux laws for diffusive convection, the authors estimate the time-averaged diapycnal heat fluxes across the four shallower layers overlying the AW core to be ~8 W m−2. Temporal variability of these fluxes is strong, with standard deviations of ~3–7 W m−2. These fluxes provide a means for effective transfer of AW heat upward over more than a 100-m depth range toward the upper halocline. These findings suggest that double diffusion is an important mechanism influencing the oceanic heat fluxes that help determine the state of Arctic sea ice.

scholarly journals Mesoscale Atlantic water eddy off the Laptev Sea continental slope carries the signature of upstream interaction

2008 ◽  
Vol 113 (C7) ◽  
Author(s):  
I. A. Dmitrenko ◽  
S. A. Kirillov ◽  
V. V. Ivanov ◽  
R. A. Woodgate
Keyword(s):  
Continental Slope ◽  
Atlantic Water ◽  
Laptev Sea ◽  
The Laptev Sea

scholarly journals Atmospheric controlled freshwater release at the Laptev Sea continental margin

2010 ◽  
Vol 30 (1) ◽  
pp. 5858 ◽  
Author(s):  
Dorothea Bauch ◽  
Matthias Gröger ◽  
Igor Dmitrenko ◽  
Jens Hölemann ◽  
Sergey Kirillov ◽  
...  
Keyword(s):  
Continental Margin ◽  
Laptev Sea ◽  
Freshwater Release ◽  
The Laptev Sea
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