Phytoplankton distribution in the coastal polynya and adjacent sea ice zone, Antarctica

Abstract

To understand the phytoplankton community in the coastal polynya and adjacent sea ice zone, field survey was conducted at 19 stations during austral summer from December 2013 to January 2014, and water samples were analyzed using a microscopy. Phaeocystis antarctica was the predominant species in the phytoplankton abundance, indicating ecological importance as a primary producer in this area. The phytoplankton abundance and biomass were higher in the polynya than sea ice zones. In the polynya, water column was stratified, and phytoplankton was predominated by P. antarctica. In the marginal sea ice zone, the dominant diatoms, Proboscia alata, Fragilariopsis curta, F. cylindrus, and Chaetoceros spp., were a minor group in terms of the phytoplankton abundance but they contributed significantly to the total phytoplankton carbon biomass due to their large size. In the glacial edge, phytoplankton abundance was lower in the surface layer but the depth-integrated abundance was higher than that in the polynya. This study shows that the sea ice influence the horizontal and vertical distribution of phytoplankton community and biomass in the Antarctic coastal area.