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| 2. |
- Anderson, Leif G, 1951, et al.
(författare)
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Out-gassing of CO2 from Siberian Shelf seas by terrestrial organic matter decomposition
- 2009
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Ingår i: Geophys. Res. Lett.. ; 36
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Tidskriftsartikel (refereegranskat)abstract
- The Siberian shelf seas cover large shallow areas that receive substantial amounts of river discharge. The river runoff contributes nutrients that promote marine primary production, but also dissolved and particulate organic matter. The coastal regions are built up of organic matter in permafrost that thaws and result in coastal erosion and addition of organic matter to the sea. Hence there are multiple sources of organic matter that through microbial decomposition result in high partial pressures of CO2 in the shelf seas. By evaluating data collected from the Laptev and East Siberian Seas in the summer of 2008 we compute an excess of DIC equal to 10 · 1012 g C that is expected to be outgassed to the atmosphere and suggest that this excess mainly is caused by terrestrial organic matter decomposition.
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| 3. |
- Andersson, P.S., et al.
(författare)
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The importance of river water inflow and shelf sediment-sea water exchange in the East Siberian Sea for the Nd isotopic composition of Arctic Ocean water
- 2009
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Ingår i: Geochimica et Cosmochimica Acta. - 0016-7037 .- 1872-9533. ; 73:13, Suppl. 1, s. A41-
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- With data generated from cruises to the Canada Basin in 2000, to the Eurasian and Central Arctic Ocean basins in 2001, to the Fram Strait in 2002 and to the Chuckchi Sea in 2005 we now have a good general view of the distribution and isotopic composition of Nd (εNd) in the Arctic Ocean [1, 2]. The restricted Arctic Ocean basin is surrounded by large continental shelves, covering more than 50% of its total area.Distinct from other oceans, with surface water Nd depletion, there is throughout the Arctic a pattern of high Nd concentrations, up to 58pM, at the surface that gradually diminish with depth to 15-18pM in the deep waters. A range of isotopic variations across the Arctic and within individual depth profiles reflects the different sources of waters. The dominant source of water and Nd is the Atlantic (εNd= -10.7). Radiogenic isotope Nd signatures can be traced in Pacific water flowing into the Canada Basin and further into the Eurasian Basin (up to εNd= -6.5). The variation of εNd and concentration in the Arctic Ocean suggest that Nd input from rivers and shelf sediments is also of great importance.Improving our understanding of the vast Siberian Shelves influence on Nd and trace element behaviour in the Arctic Ocean was one of the main objectives of the International Siberian Shelf Study 2008 (ISSS-08). The ISSS-08 cruise recovered filtered water (<0.2µm), particles and sediments from the Laptev and East Siberian Seas as well as estuarine and river water from Lena, Indigirka and Kolyma. Crucial processes, including loss of river water Nd in the estuarine region and shelf sediment-sea water exchange will be discussed in terms of controlling the Nd concentration and isotopic composition of sea water.[1] Andersson et al. (2008) GCA 72, 2854-2867. [2] Porcelli et al. (2009, in press) GCA. (2009, in press)
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| 4. |
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| 5. |
- Cooke, M.P., et al.
(författare)
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Bacteriohopanepolyol biomarker composition of organic matter exported to the Arctic Ocean by seven of the major Arctic rivers
- 2009
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Ingår i: Organic Geochemistry. - : Elsevier BV. - 0146-6380 .- 1873-5290. ; 40:11, s. 1151-1159
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Tidskriftsartikel (refereegranskat)abstract
- Bacteriohopanepolyols (BHPs) are a diverse group of membrane lipids produced by a wide variety of bacteria and can be used as molecular biomarkers for bacterial processes and populations in both modern and ancient environments. A group of BHPs, including adenosylhopane and structurally related compounds, have been identified as being specific to soils, enabling the transport of terrestrial organic matter (terrOM) to the marine realm to be monitored. Estuary surface sediment samples were obtained from the five Great Russian Arctic Rivers (GRARs: Ob, Yenisey, Lena, Indigirka and Kolyma) and river sediments were obtained from two North American Rivers (Yukon and Mackenzie). Analysis of the BHP signatures, using high performance liquid chromatography-tandem mass spectrometry (HPLC-MSn), indicated the presence of 15 different BHPs originating from a variety of different bacteria, as well as a significant presence of terrestrially derived OM. Total BHP abundance and the contribution of the "soil-marker" BHPs to the total BHP pool increased eastwards among the GRAR sediments. This suggests increasing terrestrial OM or increased preservation of OM as a result of shorter periods of permafrost thawing. The North American rivers showed greatly differing BHP levels between the Yukon and Mackenzie rivers, with a greater BHP input and thus a relatively higher soil OM contribution from the Yukon. The Indigirka River basin in the eastern Siberian Arctic appeared to be the epicentre in the pan-Arctic BHP distribution trend, with the highest "soil-marker" BHPs but the lowest tetrafunctionalised BHPs. Aminobacteriohopanepentol, an indicator of aerobic methane oxidation, was observed in all the sediments, with the source being either the marine environment or methane producing terrestrial environments.
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| 7. |
- Ingri, Johan, et al.
(författare)
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Fractionation of iron isotopes during estuarine mixing in Ob, Yenisey and Lena freshwater plumes
- 2009
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Ingår i: Geochimica et Cosmochimica Acta. - 0016-7037 .- 1872-9533. ; 73:13, Suppl. S, s. A569-
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Iron isotopes were measured in suspended matter (>0.2 µm) in the Ob, Yenisey and Lena River freshwater plumes during the International Siberian Shelf Study 2008 (ISSS-08). The δ56Fe value was around zero within the Lena River and close to the river mouth, but changed to more negative values in the outer parts of the plume. In both the Ob and Yenisey plumes suspended matter in the surface water had clearly negative values whereas samples close to the bottom showed values close to zero.It has previously been suggested that total Fe in river suspended matter (>0.2µm) in boreal regions is roughly a mixture of three phases, detrital particles (δ56Fe around zero), oxyhydroxide particles (δ56Fe positive) and C-Fe particles (δ56Fe negative). We suggest that the δ56Fe pattern observed in this study is the result of relatively rapid removal of detrital particles and Fe-oxyhydroxides, leaving a suspended fraction with negative values in the surface water in the outer parts of the freshwater plumes. Hence, during estuarine mixing of suspended particles heavy iron isotopes are deposited close to the river mouth, whereas light isotopes are exported to open ocean water.
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| 8. |
- Macdonald, R. W, et al.
(författare)
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The Arctic Ocean: budgets and fluxes
- 2006
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Ingår i: Carbon and Nutrient Fluxes in Continental Margins: A global Synthesis.
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Tidskriftsartikel (refereegranskat)
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| 9. |
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| 10. |
- Semiletov, I., et al.
(författare)
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East Siberian Shelf Study Alleviates Scarcity of Observations
- 2009
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Ingår i: EOS. - : American Geophysical Union (AGU). - 0096-3941 .- 2324-9250. ; 90:17, s. 145-
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Tidskriftsartikel (refereegranskat)abstract
- The East Siberian Arctic Shelf (ESAS) is the world's largest continental shelf and also the most understudied part of the Arctic Ocean. Composed of the Laptev Sea, the East Siberian Sea, and the Russian section of the Chukchi Sea, the ESAS is characterized by tundra discharge through the Lena, Indigirka, and Kolyma rivers; coastal erosion; methane seeps from subsea permafrost reservoirs; and the formation of water masses that spread throughout the Arctic Ocean. The region, which has experienced a 4°C springtime positive air temperature anomaly for 2000–2005 compared with preceding decades, is also of particular interest for its carbon-climate couplings.
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