Characteristics of mesozooplankton sound-scattering layer in the Pacific Summer Water, Arctic Ocean

Abstract

This study investigated the variations in the sound-scatteringlayer(SSL) that were reflected from the mesozooplankton communities around the Northwind Ridge in the western Arctic Ocean.A multi-frequency acoustic survey was conducted to reveal the SSL distribution dominated by Arctic copepodsin the early summer of 2010.The SSL distribution was well correlated with the salinity,nutrients and chlorophyll a (chl-a) associated with the features of the Pacific Summer Water(PSW).TheSSL was observed primarily in the upper most100m of the PSW,which provided a desirable habitat for Arctic copepods due to high nutrients and phytoplankton biomass.The highest density SSL was observed in the eddy-like structure of the PSW,which is most likely because of the high nutrients and chl-a. High regional densities in the SSL indicated that Arctic copepods provide a large portion of the biomass and contribution to the foodwebs in the PSW,in the western Arctic Ocean.