Community structure of zooplankton in the Bransfield Strait during the austral summer 2013

Abstract

The results of the analysis of samples of Antarctic zooplankton collected in the Bransfield Strait in February 2013 are presented. The total volume of zooplankton ranged between 3 and 305 mL/1000m3. Zooplankton consisted of copepods, euphausiids, siphonophores, gastropods, apendicularians, chaetognaths, amphipods, pteropods, ostracods, fish larvae and others. Copepods, euphausiids and siphonophores were more frequent; but copepods accounted for 76 % of the total abundance and were more diverse. Six species of fish larvae were determined, the most frequent was Notothenia kempi which was distributed near the South Shetland Islands, Admiralty Bay and southeast of the island Gibbs. The analysis of communities established 3 groups or conglomerates. The first group was the most abundant dominating Metridia gerlachei and Euphausia superba, distributed in bodies of water with temperature greater than +1 °C. The second group had low abundance, was distributed in higher salinities to 34.2 ups and closer to the Antarctic Peninsula. The third group had intermediate abundances, recorded higher community parameters and the greater abundance of Thysanoessa macrura; this group was distributed in lower salinities to 34.1 ups and mixing water with temperatures above 0 °C.