Circulation of the Western Antarctic Peninsula: Implications for Biological Production

• Main Author: Piñones Valenzuela, Maria Andrea
• Format: Text
• Language: unknown
• Published: ODU Digital Commons 2011
• Subjects: Antarctica; Euphasia superba; Ocean circulation; Krill; Marine Biology; Oceanography; Alexander Island; Antarctic; Antarctic Peninsula; Bellingshausen Sea; Crystal Sound; Laubeuf; Laubeuf Fjord; Marguerite; Marguerite Bay; Antarc*; Antarctic Krill
• Online Access: https://digitalcommons.odu.edu/oeas_etds/147; https://digitalcommons.odu.edu/cgi/viewcontent.cgi?article=1151&context=oeas_etds

The western Antarctic Peninsula (wAP) continental shelf is characterized by large persistent populations of Antarctic krill ( Enphausia superba) and by regions of enhanced concentrations of marine mammals and other predators (hot spots). This study focused on understanding the role of ocean circulation in providing retention/connectivity of wAP Antarctic krill populations and in maintaining biological hot spot regions. Numerical Lagrangian particle tracking simulations obtained from the Regional Ocean Modeling System (ROMS) configured for the wAP region provided quantitative estimates of retention, immigration and emigration from the wAP continental shelf. Additional simulations with a one-dimensional temperature-dependent growth model for krill embryos and early larval stages allowed mapping of the Lagrangian trajectories into krill developmental stages. The simulated particle trajectories showed preferred sites for across-shelf transport, with Marguerite Trough being a primary pathway for movement into Marguerite Bay, Crystal Sound, and the inner shelf regions. Residence times for the biological hot spots were 18 to 27 days for Alexander Island and Crystal Sound and almost 35 days for Laubeuf Fjord (biological hot spot regions). Particles released in the Bellingshausen Sea (remote source) were transported to the wAP shelf with a time scale consistent with the time required for Antarctic krill embryos to develop into larvae (120 days). The trajectories of floats released along the wAP shelf inside the 500-in isobath (local source) showed retention times on the order of 3 months and low connectivity among different release sites on the mid to inner shelf, suggesting that local reproduction and development can be important contributors to wAP Antarctic krill populations. Successful completion of the descent-ascent cycle of Antarctic krill embryo-larvae occurred along the outer shelf and in shelf regions where bottom depths were greater than 500 m. Estimated residence times in these areas were 20–30 days, which ...