Using pelagic ciliated microzooplankton communities as an indicator for monitoring environmental condition under impact of summer sea-ice reduction in western Arctic Ocean

Abstract

To assess the impact of arctic climate change on environmental condition and pelagic biodiversity, spa-tial variations in ciliated microzooplankton communities were studied at 32 stations (western ArcticOcean) in summer sea-ice reduction period from August 1 to September 10, 2012. Multivariate and uni-variate analyses demonstrated that ciliated microzooplankton community structures showed significantdifferences between the western and eastern parts of the sampling region consistent with east？ west dif-ferences in environmental conditions 16 dominant species (e.g., Leegaardiella ovalis, Strombidium acutum,and Mesodinium rubrum) showed the same spatial distribution pattern and were significantly correlatedwith physicochemical variables, especially with nitrates and phosphates and both spatial patterns ofcommunity structure and species diversity indices were significantly associated with environmentalcondition. These results suggest that the summer sea-ice reduction has affected ciliate biodiversity seri-ously and the pelagic ciliate communities may be useful as robust bioindicators for studying climatechange effects under increasing sea-ice melting in the Arctic Ocean.