A seasonally varying biotope at Signy Island, Antarctic: implications for meiofaunal structure

Abstract

Under the typical high-latitude conditions of temperature, productivity and settlement of chlorophyll and phaeophytin to the sediment, many benthic organisms in the Antarctic show strong seasonal variation. Although meiofauna comprise an important component of the southpolar benthic ecosystem, our knowledge of them is limited. The metazoan meiofauna and the surrounding sediments were studied fortnightly for 18 mo in a shallow bay at Signy Island (Factory Cove, South Orkneys, Antarctica) to test whether and how the temporal variability of the environment influenced meiobenthos dynamics. By examination of the distribution of the abundance and biomass of the total community, the density of higher taxonomic groups, and of individual dominant nematode genera and feeding categories, we assessed changes in faunal structure. Short-term variations were often effective, and several correlations were observed between temperature and food availability (chlorophyll and its derivatives and bulk organic matter, C and N, in both sediment and water column). However, complex temporal patterns characterised the otherwise fairly predictable seasonal variations of the Antarctic ecosystem. The results suggest that variations in meiobenthic population density and structure were primarily regulated by the input and availability of organic matter and less so by water temperature, which was constantly low. The virtual lack of a 'winter stop' also leads to the conclusion that food was not limiting in the Antarctic coastal sediment.KEY WORDS: Signy Island · Trophic relationships · Free-living marine nematodes · Bentho-pelagic coupling Resale or republication not permitted without written consent of the publisher

Influence of biotic and abiotic sediment factors on abundance and biomass of harpacticoid copepods in a shallow Antarctic bay

“…Meiofauna in Factory Cove is provided with an excess of food during the summer (C/N: 9-12 for the upper three centimeters, TOM: 2 and 4%) and copepods especially, due to highly reduced sediments, are confronted with only a few centimetres of suitable habitat. Also in Factory Cove, Vanhove et al (2000) found correlations between harpacticoid copepods on the one hand and sediment bound pigments and organic nitrogen on the other.…”

“…Firstly the mesh sizes used for sample treatment are different (see de Skowronski and Corbisier, 2002), and secondly the sampling methods are very diverse (corers placed by scuba divers: de Skowronski and Corbisier, 2002;Vanhove et al, 1998Vanhove et al, , 2000Lee et al, 2001; sub-samples from Reineck corer: de Bovée and Soyer, 1977;Soyer and de Bovée, 1977).…”

Changing chain: past, present and future of the Scotia Arc's and Antarctica's shallow benthic communities

“…the echinoid Sterechinus neumayeri, the nemertean Parborlasia corrugata and the isopod Glyptonotus antarcticus, among others. Meiofaunal patterns seem to be similar to those in the macrofauna (increases in abundance and diversity) with respect to depth (Skowronski et al, 1998;Vanhove et al, 2000;Lee et al, 2001a,b).…”

Characteristics of meiofauna in extreme marine ecosystems: a review

“…The bulk of benthic meiofauna feeds on degraded organic matter, a food source available throughout the year (VeitKöhler et al 2013). Variations in meiofauna abundance and community structure can be explained by the input and availability of organic matter (Vanhove et al 2000). Isotopic analysis on Antarctic meiofauna suggested a detrital-pool food source and/or the presence of predatory taxa (Pasotti et al 2015).…”