scholarly journals Increasing coastal slump activity impacts the release of sediment and organic carbon into the Arctic Ocean

2018 ◽  
Vol 15 (5) ◽  
pp. 1483-1495 ◽  
Author(s):  
Justine L. Ramage ◽  
Anna M. Irrgang ◽  
Anne Morgenstern ◽  
Hugues Lantuit
Keyword(s):  
Organic Carbon ◽  
Arctic Ocean ◽  
Spline Interpolation ◽  
Airborne Lidar ◽  
Aerial Photographs ◽  
The Arctic ◽  
The Arctic Ocean ◽  
Arctic Coast ◽  
Coastal Retreat ◽  
High Resolution Satellite Imagery

Abstract. Retrogressive thaw slumps (RTSs) are among the most active thermokarst landforms in the Arctic and deliver a large amount of material to the Arctic Ocean. However, their contribution to the organic carbon (OC) budget is unknown. We provide the first estimate of the contribution of RTSs to the nearshore OC budget of the Yukon Coast, Canada, and describe the evolution of coastal RTSs between 1952 and 2011 in this area. We (1) describe the evolution of RTSs between 1952 and 2011; (2) calculate the volume of eroded material and stocks of OC mobilized through slumping, including soil organic carbon (SOC) and dissolved organic carbon (DOC); and (3) estimate the OC fluxes mobilized through slumping between 1972 and 2011. We identified RTSs using high-resolution satellite imagery from 2011 and geocoded aerial photographs from 1952 and 1972. To estimate the volume of eroded material, we applied spline interpolation on an airborne lidar dataset acquired in July 2013. We inferred the stocks of mobilized SOC and DOC from existing related literature. Our results show a 73 % increase in the number of RTSs and 14 % areal expansion between 1952 and 2011. In the study area, RTSs displaced at least 16.6×106 m3 of material, 53 % of which was ice, and mobilized 145.9×106 kg of OC. Between 1972 and 2011, 49 RTSs displaced 8.6×103 m3 yr−1 of material, adding 0.6 % to the OC flux released by coastal retreat along the Yukon Coast. Our results show that the contribution of RTSs to the nearshore OC budget is non-negligible and should be included when estimating the quantity of OC released from the Arctic coast to the ocean.

scholarly journals Contribution of Coastal Retrogressive Thaw Slumps to the Nearshore Organic Carbon budget along the Yukon Coast

2017 ◽  
Author(s):  
Justine L. Ramage ◽  
Anna M. Irrgang ◽  
Anne Morgenstern ◽  
Hugues Lantuit
Keyword(s):  
High Resolution ◽  
Organic Carbon ◽  
Carbon Budget ◽  
Spline Interpolation ◽  
Airborne Lidar ◽  
Aerial Photographs ◽  
Strong Impact ◽  
Related Literature ◽  
Coastal Retreat ◽  
High Resolution Satellite Imagery

Abstract. We describe the evolution of coastal retrogressive thaw slumps (RTSs) between 1952 and 2011 along the Yukon Coast, Canada, and provide the first estimate of the contribution of RTSs to the nearshore organic carbon budget in this area. We 1) monitor the evolution of RTSs during the periods 1952–1972 and 1972–2011; 2) calculate the volume of material eroded and stocks of organic carbon (OC) mobilized through slumping – including soil organic carbon (SOC) and dissolved organic carbon (DOC) – and 3) measure the OC fluxes mobilized through slumping between 1972 and 2011. We identified 15 RTSs using high-resolution satellite imagery from 2011 and geocoded aerial photographs from 1952 and 1972. To estimate the volume of eroded material, we applied a spline interpolation on an airborne LiDAR dataset acquired in July 2013. We inferred the stocks of mobilized SOC and DOC from existing related literature. Our results show a 73 % increase in the number of RTSs between 1952 and 2011. In the study area, RTSs displaced at least 8600 × 103 m3 of material, with 53 % of ice. We estimated that slumping mobilized 81 900 × 103 kg of SOC and 156 × 103 kg of DOC. Since 1972, 17 % of the RTSs 20 have displaced 8.6 × 103 m3/yr of material, with an average OC flux of 82.5 ×103 kg/yr. This flux represents 0.3 % of the OC flux released from coastal retreat; however RTSs have a strong impact on the transformation of OC in the coastal fringe.

scholarly journals Distribution, fluxes and balance of particulate organic carbon in the Arctic ocean

2019 ◽  
Vol 59 (4) ◽  
pp. 544-552
Author(s):  
A. A. Vetrov ◽  
E. A. Romankevich
Keyword(s):  
Organic Carbon ◽  
Arctic Ocean ◽  
Particulate Organic Carbon ◽  
The Arctic ◽  
Climate Data ◽  
Arctic Seas ◽  
The Pacific ◽  
The Arctic Ocean ◽  
Main Component ◽  
Depth Horizon

Particulate organic carbon (POC) is one of main component of carbon cycle in the Ocean. In this study an attempt to construct a picture of the distribution and fluxes of POC in the Arctic Ocean adjusting for interchange with the Pacific and Atlantic Oceans has been made. The specificity of this construction is associated with an irregular distribution of POC measurements and complicated structure and hydrodynamics of the waters masses. To overcome these difficulties, Multiple Linear Regression technic (MLR) was performed to test the significant relation between POC, temperature, salinity, as well depth, horizon, latitude and offshore distance. The mapping of POC distribution and its fluxes was carrying out at 38 horizons from 5 to 4150 m (resolution 1°×1°). Data on temperature, salinity, meridional and zonal components of current velocities were obtained from ORA S4 database (Integrated Climate Data Center, http://icdc.cen.uni-hamburg.de/las). The import-export of POC between the Arctic, Atlantic and Pacific Oceans as well as between Arctic Seas was precomputed by summer fluxes. The import of POC in the Arctic Ocean is estimated to be 38±8Tg Cyr-1, and the export is -9.5±4.4Tg Cyr-1.

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 A 50 % increase in the mass of terrestrial particles delivered by the Mackenzie River into the Beaufort Sea (Canadian Arctic Ocean) over the last 10 years

2015 ◽  
Vol 12 (11) ◽  
pp. 3551-3565 ◽  
Author(s):  
D. Doxaran ◽  
E. Devred ◽  
M. Babin
Keyword(s):  
Organic Carbon ◽  
Arctic Ocean ◽  
Suspended Solids ◽  
Beaufort Sea ◽  
Freshwater Discharge ◽  
The Arctic ◽  
Field Observations ◽  
The Arctic Ocean ◽  
Arctic Rivers ◽  
Mackenzie River

Abstract. Global warming has a significant impact on the regional scale on the Arctic Ocean and surrounding coastal zones (i.e., Alaska, Canada, Greenland, Norway and Russia). The recent increase in air temperature has resulted in increased precipitation along the drainage basins of Arctic rivers. It has also directly impacted land and seawater temperatures with the consequence of melting permafrost and sea ice. An increase in freshwater discharge by main Arctic rivers has been clearly identified in time series of field observations. The freshwater discharge of the Mackenzie River has increased by 25% since 2003. This may have increased the mobilization and transport of various dissolved and particulate substances, including organic carbon, as well as their export to the ocean. The release from land to the ocean of such organic material, which has been sequestered in a frozen state since the Last Glacial Maximum, may significantly impact the Arctic Ocean carbon cycle as well as marine ecosystems. In this study we use 11 years of ocean color satellite data and field observations collected in 2009 to estimate the mass of terrestrial suspended solids and particulate organic carbon delivered by the Mackenzie River into the Beaufort Sea (Arctic Ocean). Our results show that during the summer period, the concentration of suspended solids at the river mouth, in the delta zone and in the river plume has increased by 46, 71 and 33%, respectively, since 2003. Combined with the variations observed in the freshwater discharge, this corresponds to a more than 50% increase in the particulate (terrestrial suspended particles and organic carbon) export from the Mackenzie River into the Beaufort Sea.

scholarly journals Lidar-Derived Particle Concentrations in Plumes from Arctic Leads

1990 ◽  
Vol 14 ◽  
pp. 9-12 ◽  
Author(s):  
Edgar L. Andreas ◽  
Martin W. Miles ◽  
Roger G. Barry ◽  
Russell C. Schnell
Keyword(s):  
Arctic Ocean ◽  
Supercooled Water ◽  
Airborne Lidar ◽  
The Arctic ◽  
Water Droplets ◽  
Surface Source ◽  
The Arctic Ocean ◽  
Lidar Equation

With an airborne lidar, we have observed massive plumes of condensate particles rising from wintertime leads in the Arctic Ocean. Some of these plumes reached an altitude of 4 km; some extended over 200 km down-wind from their surface source. Here we invert the lidar equation and use lidar backscatter data to infer particle concentrations within two such plumes. Assuming that the plumes consist of supercooled water droplets of radius 5 μm, we estimate typical concentrations of 3–6 × 105 droplets m-3 just above the leads. Concentrations within the plumes can still be as high as 104 droplets m-3 at an altitude of 3 km and 200 km down-wind from some leads. Had we assumed that the plume particles are ice spheres of radius 40 μm, concentrations would be just 100 times less than these.

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