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Organic carbon and nitrogen composition in the sediment of the Kara Sea, Arctic Ocean during the Last Glacial Maximum to Holocene times
Author(s) -
Kang HwaSeong,
Won EunJi,
Shin KyungHoon,
Yoon Ho il
Publication year - 2007
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2007gl030068
Subject(s) - last glacial maximum , holocene , deglaciation , geology , sediment , oceanography , total organic carbon , geomorphology , environmental chemistry , chemistry
A sharp decrease in C org /N tot ratios and apparently heavier stable isotope ratios of C org and N tot ( δ 13 C org and δ 15 N tot ) after deglaciation were observed in sediment cores St‐25 and St‐34 collected from the Saint Anna Trough in the Kara Sea, exhibiting a change of sediment origin from terrestrial to marine during the LGM and Holocene times. Organic nitrogen (N org ) contributed about 40% to total nitrogen (N tot ) during the Holocene, but the N org fraction was hardly observed in the lower LGM sediments (below 120 cm depth in St‐25 and beneath 170 cm in St‐34). This may be due to a permanent cover of sea ice in the area during the LGM. In addition, the δ 13 C values for OC labile and OC resi were remarkably different between LGM and Holocene sediment. The unexpected lighter δ 13 C values for OC resi for the LGM period might be due to methanotrophic bacteria in the sediment of Kara Sea.