Community structure of macrobenthos along bathymetrical transects off Svalbard and Eastern Greenland - A comparative study at the deep-sea observatory HAUSGARTEN
The Fram Strait is one of the most important gateways between the Arctic Ocean and its connected water bodies as it is the deepest passage and therefore provides exchanges of deep waters. The part of the eastern Fram Strait is significantly influenced by the northern-bound warm West Spitsbergen Curr...
| Main Authors: | , , |
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| Format: | Conference Object |
| Language: | unknown |
| Published: |
2017
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| Subjects: | |
| Online Access: | https://epic.awi.de/id/eprint/41752/ https://hdl.handle.net/10013/epic.49900 |
| Summary: | The Fram Strait is one of the most important gateways between the Arctic Ocean and its connected water bodies as it is the deepest passage and therefore provides exchanges of deep waters. The part of the eastern Fram Strait is significantly influenced by the northern-bound warm West Spitsbergen Current (WSC) whereas the western part is influenced by the cold and less saline East Greenland Current (EGC) flowing southerly direction. Sea ice from the Arctic Ocean is passing the Fram Strait on its southward flow. Sea ice loss is affecting the entire marine ecosystem as vertical energy fluxes are coupled even to the deep sea. The objective of this study is to investigate whether there are dissimilarities in deep-sea benthic macrofaunal communities such as species composition and diversity in eastern and western parts of the Fram Strait due to different energy input to the benthic communities. Sampling sites along the bathymetric transect of the LTER (Long-Term Ecology Research) observatory HAUSGARTEN off western Svalbard and the macrofauna sampling methodology were chosen following previous studies, while the East Greenland slope has been sampled for the first time at this location. Samples were taken during RV Polarstern expedition PS99.2 in June/July 2016 using an UNSEL box corer with a sampling area of 0.25 m² at water depths of 1000 - 5500 m (Vestnesa Ridge) and 1000 - 2500 m (East Greenland slope). Samples were washed through a 500 μm mesh size sieve and fixed in ethanol 96 %. Macrobenthic organisms were identified to the lowest possible taxonomical level in the laboratory after the expedition. Recent results suggest a trend that stations located on the East Greenland slope are lower in species richness (total number of species) but higher in diversity of taxa than stations on the Vestnesa Ridge. Polychaeta are the dominant taxa at both bathymetrical transects but in noticeably varying proportions. Oweniidae and Cirratulidae show among other families highest abundance at both transects. The differences in macrofauna community structure in the western and eastern Fram Strait might be a result of differences in food availability. Sea ice coverage as well as regions of contrasting primary production could be crucial factors driving community patterns. |
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