Distribution patterns of polychaete fauna in an Arctic fjord (Hornsund, Spitsbergen)

Abstract

Polychaetes are one of the most important groups of benthic organisms in marine ecosystems. They dominate on the Arctic shelf and play an important role in ecosystem functioning. This study focuses on the polychaete biodiversity and their distribution patterns in Hornsund, an open glacial fjord, in western Spitsbergen and provides important baseline data for future studies of temporal fluctuations in benthic fauna. The main aim of this study was to assess how the polychaete abundance, biomass, diversity, community structure, and function vary along the Hornsund fjord's axis, in relation to the environmental factors. Eighty-eight polychaete taxa were identified; an average density was 457 ind. m -2 ± 237.5 SD. Three assemblages were distinguished (INNER, MIDDLE, and OUTER) along the fjord axis, reflecting the intensity of glacial disturbance. A clear division between the highly disturbed inner part of the fjord (Brepollen) and the less impacted middle and outer parts was observed. Continuous gradients in abundance, biomass, and diversity were found with all those values diminishing toward the inner region of the fjord. The polychaete assemblages' indices were significantly correlated with bottom temperature, sediment characteristics (grain size), and distance to the glacier (longitude). No significant correlations were found with depth or total organic carbon content. Carnivore and motile surface deposit feeding polychaete species dominated in the areas close to the glaciers, while the OUTER community was dominated by carnivores and surface sessile and discretely motile species, and had more complex trophic structure, with multiple species representing different functional groups including carnivores, sessile, discretely motile, and motile surface deposit feeders and motile burrowers.

Distinct or similar? Soft bottom polychaete diversity in Arctic and Antarctic glacial fjords

“…Studies of polychaete diversity in Ezcurra Inlet and in Admiralty Bay as a whole showed high number of polychaete assemblages associated with different microhabitats (Siciński, 2004;Pabis & Siciński, 2010), while in Kongsfjorden the character of bottom deposits was less diversified resulting in more simple assemblage differentiation into three main faunal groupings associated with the inner, middle and outer areas of this inlet (Włodarska-Kowalczuk & Pearson, 2004). A similar pattern was also observed in Hornsund (Kędra et al, 2013). Our small scale study was focused on two clearly defined similar habitats to allow for more reliable comparisons.…”

Recent distribution of Echinodermata species in Spitsbergen coastal waters

“…The number of sampling points was high, although the samples were not distributed on a regular grid, as is recommended for species distribution modelling (Drewnik et al 2016b). However, the set of species collected in the present study seems to be very complete, considering the obtained species accumulation curve (a similar result was obtained for other taxa collected in our projects; e.g., Kędra et al 2013). We found four new species for the area, including a single specimen of Acantotrochus mirabilis, which is a deep-water holothurian that has also been reported from Norwegian and Greenland seas below depths of 1000 m (Gebruk et al 2014), but our record is a distinctly shallow one (250 m Brought to you by | MIT Libraries Authenticated Download Date | 5/10/18 2:20 PM all of wide boreal or circumpolar distributions, are known from Norway but had not been recorded so far north.…”

Low abundance and high species richness: the structure of the soft-bottom isopod fauna of a West Antarctic glacial fjord

“…The much lower abundance and diversity of the isopod fauna in the Ezcurra Inlet, compared to the central basin of the Admiralty Bay, can be quite easily explained by the differences in the hydrological and sedimentary regimes (Pecherzewski 1980;Szafranski and Lipski 1982;Rudowski and Marsz 1996;Siciński 2004;Campos et al 2013). Glacial fjord fauna is generally impoverished in terms of biodiversity and abundance on account of various types of disturbance, such as increased mineral sedimentation and silting of bottom deposits (Włodarska-Kowalczuk and Pearson 2004;Siciński et al 2011;Kędra et al 2013). Generally, a gradual increase in macrofaunal abundance and diversity is observed along the polar fjord axis, and is accompanied by changes in species composition (Siciński 2004;Włodarska-Kowalczuk and Pearson 2004;Kedra et al 2013).…”