Timing of sea ice retreat can alter phytoplankton communitystructure in the western Arctic Ocean

[摘要] This study assesses the response of phytoplankton assemblages to recentclimate change, especially with regard to the shrinking of sea ice in thenorthern Chukchi Sea of the western Arctic Ocean. Distribution patterns ofphytoplankton groups in the late summers of 2008–2010 were analysed basedon HPLC pigment signatures and, the following four major algal groups wereinferred via multiple regression and cluster analyses: prasinophytes,diatoms, haptophytes and dinoflagellates. A remarkable interannualdifference in the distribution pattern of the groups was found in thenorthern basin area. Haptophytes dominated and dispersed widely in warmsurface waters in 2008, whereas prasinophytes dominated in cold water in2009 and 2010. A difference in the onset date of sea ice retreat was evidentamong years–the sea ice retreat in 2008 was 1–2 months earlier than in2009 and 2010. The spatial distribution of early sea ice retreat matched theareas in which a shift in algal community composition was observed.Steel-Dwass's multiple comparison tests were used to assess the physical,chemical and biological parameters of the four clusters. We found astatistically significant difference in temperature between thehaptophyte-dominated cluster and the other clusters, suggesting that thechange in the phytoplankton communities was related to the earlier sea iceretreat in 2008 and the corollary increase in sea surface temperatures.Longer periods of open water during the summer, which are expected in thefuture, may affect food webs and biogeochemical cycles in the western Arcticdue to shifts in phytoplankton community structure.

[学科分类] 地球化学与岩石