Pelagic ciliate communities within the Amundsen Sea polynya and adjacent sea ice zone, Antarctica

Abstract

Polynyas, areas of open water surrounded by sea ice, are sites of intense primary production and eco-logical hotspots in the Antarctic Ocean. This study determined the spatial variation in communities of pelagic ciliates in an Amundsen Sea polynya (ASP) and adjacent sea ice zones (SIZ) during austral summer from February to March 2012, and the results were compared with biotic and abiotic envir- onmental factors. The species number, abundance and biomass were higher in the ASP than SIZ. Cano-nical analysis indicated that the communities in the ASP were distinct from those under the sea ice. The pelagic ciliate community structure was closely correlated with environmental variability. Several pri-mary environmental variables, both alone and in combination, were found to affect community spatial patterns. The ciliate biomasses in the ASP and SIZ areas were both significantly correlated with total and nano-Chl a. This analysis of the ciliated microzooplankton communities associated with high primary production provides new insights into the roles of ciliates in biogeochemical cycles in high-latitude polynyas. Additionally, our findings provide detailed data on the composition, distribution, and structure of polynya ciliate communities in the Amundsen Sea.