Phytoplankton distribution in unusually low sea ice cover over the Pacific Arctic

[摘要] A large part of the Pacific Arctic basin experiences ice-free conditions insummer as a result of sea ice cover steadily decreasing over the lastdecades. To evaluate the impact of sea ice retreat on the marine ecosystem,phytoplankton in situ observations were acquired over the Chukchi shelf andthe Canadian basin in 2008, a year of high melting. Pigment analyses andtaxonomy enumerations were used to characterisethe distribution of mainphytoplanktonic groups. Marked spatial variability of the phytoplanktondistribution was observed in summer 2008. Comparison of eight phytoplanktonfunctional groups and 3 size-classes (pico-, nano- and micro-phytoplankton)also showed significant differences in abundance, biomass and distributionbetween summer of low ice cover (2008) and heavy ice summer (1994).Environmental parameters such as freshening, stratification, light andnutrient availability are discussed as possible causes to explain theobserved differences in phytoplankton community structure between 1994 and2008.

[学科分类] 地球化学与岩石