Using Antarctic krill (Euphausia superba) to reflect regional heterogeneity in marine environments in the northern Antarctic Peninsula, Antarctic

The northern Antarctic Peninsula (NAP) supports a few human activities. It is affected by intense climate change and anthropogenic threats. Antarctic krill (Euphausia superba) is the largest, by mass, in the Southern Ocean and is the keystone species in the Antarctic ecosystem. In this study, we report the concentrations of trace elements, i.e., zinc [Zn], copper [Cu], cadmium [Cd], and lead [Pb], in krill in three hydrographic settings of the NAP to explore the suitability of krill as a bioindicator of trace elements to reflect the heterogeneity in marine environments in this area. The following element-concentration ranking was recorded for all regions: Cu > Zn > Pb > Cd, showing that the Cu concentration is comparable to the Zn concentration in krill, and those concentrations are higher at two orders of magnitude than the Pb and Cd concentrations in krill. The Pb concentration is highest in the western basin (WB) of the Bransfield Strait, followed by the central basin (CB) of the Bransfield Strait and the north shelf (NS) of the South Shetland Islands. Lowest levels of Cu, Zn and Cd are detected in NS compared to the levels of those elements in the other two regions. There is a significant negative correlation in the Cd level in krill between NS and CB. We also discuss the processes of hydrographic dynamics transporting trace elements in NAP. Collectively, these results suggest krill is a suitable and effective bioindicator for reflecting regional heterogeneity in marine environments in NAP. We therefore suggest the krill management and design of data layers need consider such regional heterogeneity of marine environments.