Distribution of the main taxa and dominant species of macrobentos in the seas of the East Arctic

Abstract

Macrobenthos of soft bottoms on the shelf of two Arctic seas was investigated in the survey conducted aboard RV TINRO in August-September 2015. The area of 32,800 km2 in the depth range of 15–34 m was researched in the East Siberian Sea where 13 taxonomic groups of bottom fauna were found, mainly Bivalvia (75.9 % by biomass). The area of 22,500 km2 in the depth range of 45–96 m was surveyed in the Laptev Sea, where 20 groups of macrobenthos were identified, with predominance of Polychaeta (34.1 %), Bivalvia (27.7 %), and Sipuncula (21.2 %), by biomass. Significant changes in structure of benthic communities are revealed on the external shelf of the Laptev Sea (below of 70 m), in comparison with the data of previous years, possibly caused by warming of the environments: the previously dominated group of Ophiuroidea was replaced by Sipuncula. Although the dominant groups were widely occurred, their quantitative distribution was neither uniform nor similar. The dominant species had different trophic habits and occupied disjointed zones with domination of sestonophages or detritophages, in dependence on the habitat conditions. The average abundance and biomass of macrobenthos were assessed as 881 ± 174 ind./m2 and 149.2 ± 25.5 g/m2 in the East Siberian Sea, and 251 ± 32 ind./m2 and 71.0 ± 13.0 g/m2 in the Laptev Sea, respectively.

Keywords

• macrobenthos
• benthos distribution
• benthos abundance
• benthos biomass
• east siberian sea
• laptev sea