Megabenthic commmunities in the waters around Svalbard

Abstract

Composition and distribution of megabenthic communities around Svalbard were investigated in June/July 1991 with 20 Agassiz trawl and 5 bottom trawl hauls in depths between 100 and 2100 m. About 370 species, ranging from sponges to fish, were identified in the catches. Species numbers per station ranged from 21 to 86. Brittle stars, such as Ophiacantha bidentara, Ophiura sarsi and Ophiocten sericeum, were most important in terms of constancy and relative abundance in the catches. Other prominent faunal elements were eunephthyid alcyonarians, bivalves, shrimps, sea stars and fish (Gadidae, Zoarcidae, Cottidae). Multivariate analyses of the species and environmental data sets showed that the spatial distribution of the megabenthos was characterized by a pronounced depth zonation: abyssal, bathyal, off-shore shelf and fjordic communities were discriminated. However, a gradient in sediment properties, especially the organic carbon content, seemed to superimpose on the bathymetric pattern. Both main factors are interpreted as proxies of the average food availability, which is, hence, suggested

Environmental factors structuring Arctic megabenthos—a case study from a shelf and two fjords

“…However, warming will also potentially increase glacier activity, calving, and sedimentation (Hodson and Ferguson, 1999;Włodarska-Kowalczuk and Weslawski, 2001), which may in turn decrease megafaunal biomass and megabenthic functioning in north Svalbard. It is well documented that heavy inorganic sedimentation leads to reduced diversity and functional diversity of macrobiota (Syvitski et al, 1989;Piepenburg et al, 1996;Włodarska-Kowalczuk and Weslawski, 2001;Włodarska-Kowalczuk, 2007) and inorganic sedimentation can also reduce mesoscale heterogeneity of the benthic community (Włodarska-Kowalczuk and Weslawski, 2008). The diverse communities at stations 15 and 16 in outer Rijpfjorden and at stations on the shelf have a variety of trophic groups.…”

“…Generally, a decline in diversity is observed from outer to inner fjords, and this is usually attributed to gradients of glacial sedimentation (Görlich et al, 1987;Włodarska-Kowalczuk et al, 2005. Benthic megafaunal biomass and diversity are also generally lower in Arctic fjords compared to the shelf, a pattern that again is attributed to inorganic sedimentation (Syvitski et al, 1989;Piepenburg et al, 1996;Grange and Smith, 2013).…”

The significance of depth and substratum incline for the structure of a hard bottom sublittoral community in glacial Kongsfjorden (Svalbard, Arctic)—an underwater imagery approach

“…Investigations on deeper hard bottom communities in the Arctic are scarce, and existing knowledge is based on qualitative dredge hauls (e.g. for Kongsfjord-Renna 960 m see Piepenburg et al 1996). Hop et al (2002) stated that motile species and fragments of sessile organisms predominate in such samples, which frequently include the sea stars Crossaster papposus, Henricia sp.…”

Community characteristics of macrobenthos in waters around the Nature Reserve of the Chinese sturgeon Acipenser sinensis and the adjacent waters in Yangtze River Estuary

“…1). Epifauna samples were collected using an Agassiz trawl (AGT) (Piepenburg et al., 1996). The opening of the AGT was 1.5 m wide, 0.5 m high and 2.5 m long, and its mesh size in the cod‐end was 5 mm.…”