Factors dominating bacterioplankton abundance and production in Norwegian and Chukchi Seas in summer

Lead Author Jianfeng, HE
Institution Contact Polar Research Institute of China 451 Jinqiao Rd., Shanghai 200136 P. R. China
Co-Authors Yuan GAO, Xiamen University, Xiamen 361005, P. R. China; Min CHEN, Xiamen University, Xiamen 351005, P. R. China; Ling LIN, Polar Research Institute of China, Shanghai 200136, P. R. China; Fan ZHANG, Polar Research Institute of China, Shanghai 200136, P. R. China.
Theme Theme 1: Vulnerability of Arctic Environments
Session Name 1.8 Novel approaches to communicate research facts and predictions of the future of Arctic marine biota to non-scientific stakeholders
Presentation Type Poster
Abstract text Bacterial abundance in Norwegian Sea is from 0.75×108 cells/L to 15.12×108 cells/L, with an average of 3.31×108 cells/L. Bacterial production is between 0.13 mg C m-3 d-1 to 0.84 mg C m-3 d-1, averaging 0.46 mg C m-3 d-1. In Chukchi Sea, bacterial abundance is between 0.56×108 cells/L and 6.41×108 cells/L. The average is 2.25×108 cells/L. Bacterial production is from 0.042 mg C m-3 d-1 to 1.92 mg C m-3 d-1, averaging of 0.54 mg C m-3 d-1. Bacterial abundance in these two seas shows a significant difference mainly caused by temperature, while production shows no difference. High temperature results in high bacterial abundance, but the response of bacteria is insensitive. Bacterial production in both Norwegian and Chukchi Seas is far less than primary production, which means that these two areas are autotrophic.
Based on the slope of lg bacterial biomass versus lg bacterial production, bacterial communities in Norwegian and Chukchi Seas are mainly dominated by top-down control, which means grazing pressure and viral lysis are constrained factors. And this is partly reflected by the multivariable linear regression in which bacterial production is only correlated with Chl a. Under this conclusion, environmental change in polar areas appears to be more influential to microbes in Chukchi Sea than Norwegian Sea.