Carbon and nitrogen isotope signatures of deep-sea meiofauna in the Southern Ocean reflect geographical and oceanographical patterns
Carbon (δ13C) and nitrogen (δ15N) stable isotope values of deep-sea benthic copepods, nematodes, and sediments were determined along a latitudinal transect covering bathyal and abyssal depths in the Southern Ocean and the Weddell Sea (49° S to 70° S). This is the first time geographically interpreta...
| Main Authors: | , , , , |
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| Format: | Article in Journal/Newspaper |
| Language: | unknown |
| Published: |
PERGAMON-ELSEVIER SCIENCE LTD
2012
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| Subjects: | |
| Online Access: | https://epic.awi.de/id/eprint/26018/ https://hdl.handle.net/10013/epic.41580 |
| Summary: | Carbon (δ13C) and nitrogen (δ15N) stable isotope values of deep-sea benthic copepods, nematodes, and sediments were determined along a latitudinal transect covering bathyal and abyssal depths in the Southern Ocean and the Weddell Sea (49° S to 70° S). This is the first time geographically interpretable stable isotope data including δ15N are presented for deep-sea meiofauna. In agreement with previous findings on isotopic patterns of sea-surface organic matter, the deep-sea meiofauna δ13C and δ15N values gradually declined with latitude. The southernmost Lazarev Sea station was an exception to this trend. A long-lasting sea-ice cover and a primary production dominated by 13Cenriched ice algae lead to isotopic signals that were heavier than expected for this latitude. The greatest 13C depletions were found in the communities of Maud Rise. Compared to the Weddell Sea and the Lazarev Sea, this seamount region is first free of ice and thus earlier and longer under influence of the isotopically lighter water column diatoms. The prevailing oceanographic conditions additionally favor an enhanced transportation velocity of surface POM to the seafloor at Maud Rise. Generally small offsets between calculated surface δ13CPOM values and the deep-sea organisms suggested a strong bentho-pelagic coupling. Benthic copepods and nematodes seem to be primary or secondary consumers of planktonic detritus. Meiofauna individual numbers and community composition did not differ distinctly along the transect spanning a distance of 2400 km and covering a range of 3400 m water depth. This observation can be attributed to the overall low and patchy organic C fluxes to the seafloor |
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