Phytoplankton in the embayments of King George Island (Antarctic Peninsula): a review with emphasis on diatoms

Abstract

ABSTRACTConsidering that phytoplankton assemblages are good bioindicators of environmental conditions, the sensitivity of the Western Antarctic Peninsula (WAP) to climate change, and the importance of some areas of its islands as Antarctic Specially Managed Areas, this work assembles published datasets on phytoplankton biodiversity and ecology in confined coastal areas (embayments) of King George Island, WAP. Over 33 years (1980–2013), 415 species from 122 genera have been identified to species level, being mostly diatoms (371 species), with 10 new species described with local material (6 diatoms, 4 cyanobacteria). The importance of diatoms was indicated by the frequent occurrence ofCorethron pennatum,Pseudogomphonema kamtshaticum, and abundant benthic genera in the plankton (e.g.Navicula,Cocconeis). The increased contribution of dinoflagellates after 2010 suggests marked changes in the water column. Early-summer blooms differ between the bays' eastern and western shores, with terrestrial melting and wind-driven upwelling inducing the dominance of benthic species at eastern shores, whereas planktonic diatoms (Thalassiosira,Pseudo-nizschia, andChaetoceros) are most abundant along western shores and central areas. The importance of an accurate identification of organisms that are becoming key ecological components of the region is discussed, as recent changes in the microflora may affect the entire marine food web.