Abstract:

Field measurements and samplings were conducted during the 5th Chinese National Arctic Research Expedition in Summer 2012. Pyrosequencing was used to study the picoeukaryote community structure and correlation analysis was conducted to reveal the relationship between picoeukaryotes and environmental factors in the Chukchi Sea. The results show that Mamiellophyceae (37.5%), Chrysophyceae (36.4%), Dinophyceae (8.9%), Tremellomycetes (7.1%), Mediophyceae (2.4%), and Spirotrichea (1.1%) are the dominant groups at the class level. Picophytoplankton accounted for 85.2% of the picoeukaryotes in the Chukchi Sea, which indicates that the community was at the stage of rapid growth. Spearman analysis shows that environmental factors play an important role in the community structure of picophytoplankton. Mediophyceae had a very significant positive correlation with NO3– (P < 0.01) and a significant positive correlation with salinity and NO2– (P < 0.05). NO3– had a significant negative influence on Mamiellophyceae (P < 0.05). The results suggest that the nitrogen limitation of the Arctic Ocean and the rapidly melting sea ice affect the structure and spatial distribution of picoeukaryotes and that further attention is needed in the future.

Key words: picophytoplankton, picozooplankton, fungi, Spearman correlation analysis, Chukchi Sea