Spatial dynamics of macrofauna with special reference to bivalve molluscs in the Arctic Kongsfjord, Svalbard, Norway

Abstract

The current study is based on benthic samples collected as a part of the Indian Arctic Expedition, from eight stations of varying depths (29 m–292 m). The study focused on the community pattern of macrobenthos in the inner and outer fjord areas of Kongsfjord, with an emphasis on the bivalve community and the main factors affecting its distribution. The macrofaunal community was mainly composed of foraminiferans, nematodes, polychaetes, gastropods, bivalves, ostracods, copepods, amphipods and fish larvae. As most of the macrofaunal taxa were less sensitive to glacial-derived sedimentation process, their abundance was higher towards the inner fjord areas. Among the major taxa 14 species of foraminiferans, 18 species of nematodes, 8 species of polychaetes and 19 species of bivalves were identified. Across the entire study area, the bivalve Yoldiella sp. (15%) had the highest relative abundance. There is significant variation in the diversity and distribution of bivalves in the outer and inner fjord. The spatial distribution of bivalves showed that, stations 3, 4 and 5 had the highest numerical abundance compared to other. The canonical correspondence analysis (CCA) revealed that faunal distribution is mainly influenced by depth, salinity, sediment granulometry, and organic carbon content.