Diatom assemblages from coastal settings of West Antarctica

• Four diatom assemblages were identified in West Antarctic coastal settings along a 2500 km transect
• Three pelagic assemblages are related to different sea-ice duration, SST, and other conditions affecting primary production
• One diatom assemblage is dominated by benthic and epiphytic taxa, typical of nearshore, shallow-water habitats
• Chaetoceros resting spores are an important component of diatom assemblages
• Along the NW coast of the AP, sedimentation rates strongly influence total diatom concentrations
• Relative abundances of Chaetoceros is less affected by terrigenous flux and may serve as a proxy for primary production

Diatom assemblages from 33 core-tops, collected along a 2500 km transect of the northern Antarctic Peninsula and Pine Island Bay areas, were examined for their use as paleoenvironmental proxies. Environmental affinities of assemblages were interpreted within a broad geographical context and a wide range of ecological conditions. Four major assemblages were identified: three pelagic assemblages related to different sea-ice duration, SST, and other conditions affecting primary production, and one benthic and epiphytic-dominated assemblage typical of near-shore, shallow-water habitats. Chaetoceros resting spores are an important component of diatom assemblages. Their high concentrations may reflect increased primary production and are associated with low total assemblage diversities. The lowest diversities are observed at sites with increased resting spore percentages. Along the NW coast of the Antarctic Peninsula, sedimentation rates strongly influence total diatom concentrations. By contrast, relative abundances of Chaetoceros resting spores remain mostly unaffected by terrigenous flux and may serve as a reliable proxy for primary production. This broad sampling of Antarctic coastal environments fills a gap in our knowledge of phytoplankton communities in polar regions and helps establish the framework for reconstructing paleoenvironments from the paleorecord.