Study on diel migration of zooplankton in the Arctic surrounding seas during summer season based on mathematical statistics

Marine zooplankton have diel vertical migration behavior and play a key role in the transport of surface organic compounds to the deep ocean, which is of great significance in studying marine climate change. In this research, the manual visual interpretation method was used to preprocess the biological backscattering intensity data of acoustic Doppler current profiler (ADCP) during the eighth Arctic expedition. Results showed that the extracted vertical migration trajectory was in good agreement with the variation of backscattering intensity data. The amount of zooplankton in the Arctic Ocean is significantly lower than that in the North Pacific and the North Atlantic, and sea ice cover has a significant effect on the diel vertical migration of zooplankton. Characteristics of zooplankton distribution in the North Atlantic Ocean were analyzed based on mathematical statistical methods. The results also prove that the backscattering intensity of -90dB can distinguish scattering layer and water, and that of -78dB can distinguish general scatters and zooplankton. There are two significant concentrations of zooplankton in the Atlantic Ocean which were located at the surface and at depths of 350-450 m, respectively.