Macrozoobenthos of the shallow waters of Pechora Bay (SE Barents Sea)

Abstract

Macrozoobenthic communities provide vital ecosystem services including habitats and foraging resources for other species in all marine ecosystems. Although macrozoobenthos of deeper parts of the Pechora Sea (SE Barents Sea) have been studied in more detail, there is a lack of research in shallow waters of the Pechora Bay. The study area lies within the Nenetsky State Nature Reserve, established in 1997, to protect important breeding and moulting grounds of waterfowl. Macrozoobenthos provide key foraging resources for waterfowl in the nature reserve, however, there is a mismatch between ornithological and macrobenthic data. Eight stations were studied along the Russky Zavorot Peninsula in the Pechora Bay on a depth of 1.1–1.8 m within the near-shore zone of the Nenetsky State Nature Reserve in August 2016. A monodominant community of Limecola balthica with a biomass of 21.31 ± 0.32 g/m2 and 14 species in total was recorded across the area. The dominant species of the community correspond to those in the community of L. balthica recently described from the central estuarine part of the Pechora estuary. A low biomass and poor species richness in the L. balthica community support the earlier published results for the northern part of the bay and indicate the dependence of the community characteristics on environmental factors. The paucity of macrozoobenthos in the area is likely attributed to extreme environmental conditions including the following: (1) the water column freezes to the bottom during winter in the shallows of the Pechora estuary or (2) the freshwater flow spreads under the ice, severely impacting salinity. Hence the community is comprised of eurythermal and euryhaline forms and is reduced in biomass. It is unlikely that the shallows of the Russky Zavorot Peninsula play an important role as feeding grounds for benthic predators since a low in biomass barren community of a burrowing mollusc L. balthica does not provide enough foraging resources to feed stocks of waterfowl. The L. balthica-community could be used as an indicator of climate changes in the future – it is predicted that a reduction in sea ice volume will improve conditions for growth of L. balthica and may therefore lead to an increased body size and biomass of bivalves in the shallows.

Keywords

• arctic
• biomass
• estuary
• limecola balthica
• macrobenthic community