Seasonal variability of meio- and macrobenthic standing stocks and diversity in an Arctic fjord (Adventfjorden, Spitsbergen)

Abstract

Strong environmental seasonality is a basic feature of the Arctic system, still there are few published records of the seasonal variability of the Arctic marine biota. This study examined the year-round seasonal changes of soft bottom macro-and meiobenthic standing stocks and diversity on a station located in an Arctic fjord (Adventfjorden, Spitsbergen). The seasonality observed in benthic biota was related to the pelagic processes, primarily the seasonal fluxes of organic and inorganic particles. The highest abundance, biomass and richness of benthic fauna occurred in the spring after the phytoplankton bloom. During the summer, when a high load of glacial mineral material was transported to the fiord, the number of both meio-and macrobenthic individuals decreased remarkably. The strong inorganic sedimentation in summer was accompanied by a decline in macrobenthic species richness, but had no effects on evenness. Redundancy analysis (RDA) pointed to granulometric composition of sediments (depended on mineral sedimentation) and organic fluxes as factors best related to meio-and macrobenthic taxonomic composition, but no clear seasonal trend could be observed on the nMDS plots based on meiobenthic higher taxa or macrobenthic species abundances in the samples. This study addresses the possible effects of changes in the winter ice cover on the fjordic benthic systems because it was performed in a year with no ice cover on the fjord.

Do benthic meiofaunal and macrofaunal communities respond to seasonality in pelagial processes in an Arctic fjord (Kongsfjorden, Spitsbergen)?

“…For meiofauna, little response in the abundance was recorded after the sedimentation of the spring phytoplankton at the Alaskan shelf by Fleeger et al (1989) or in a North Water Polynyas by Ambrose and Renaud (1997). On the other hand, Pawłowska et al (2011) reported a clear signal of increased abundance and biomass of meiofauna and macrofauna after the spring bloom at soft-bottom shallow (30 m) station located in Adventfjorden, a small basin influenced by a glacial river inflow. Also, Morata et al (2015) reported that in Rijpfjorden-a fjord located off Nordaustlandet Island (Svalbard Archipelago)-the macrobenthic biomass (at depths below 200 m) was lower in winter (January) than that recorded by previous studies performed in the same locality in summer season (Carroll and Ambrose 2012).…”

The amphipod scavenging guild in two Arctic fjords: seasonal variations, abundance and trophic interactions

“…The rivers also bring a lot of suspended terrigenous particles, increasing the turbidity in the water during the melt period. The sedimentation rate of inorganic particles is 60 to 80 g m −2 d −1 (Zaja˛czkowski et al 2010) and as a result the bottom in the fjord consists mainly of silt (Pawłowska et al 2011). In the outer part of Adventfjorden the sedimentation rate of suspended particles is reduced and the sediment is coarser (Zaja˛czkowski 2008).…”

Contribution towards a morphological and molecular taxonomic reference library of benthic marine diatoms from two Arctic fjords on Svalbard (Norway)

“…Its depth is from 70 to 100 m. The air temperature ranges between -15 and ?5°C. The Adventfjorden system is affected by two huge river systems which enter the fjord at the inner part, bringing melt waters from glaciers located kilometres away from the coast (Pawłowska et al 2011).…”