Glacial influence on the composition and diversity of the marine phytoplankton community in Admiralty Bay, King George Island, Antarctica; Influencia glaciar en la composición y diversidad de la comunidad del fitoplancton marino en Bahía Almirantazgo, Isla Rey Jorge, Antártida

Abstract

Climate change has contributed to rapid glacier retreat in the West Antarctic Peninsula, with potential implications for marine ecosystems, particularly phytoplankton communities. In this study, we examined the influence of glacier proximity on phytoplankton composition in Admiralty Bay, Antarctica, during the austral summer of 2020. In total, 12 sampling stations were established at various distances from the glacier front to collect water samples at 3 depths to quantitatively analyze phytoplankton. The community in all stations was found to be dominated by nanoflagellates (<20 µm) (95.5%), followed by diatoms (4.02%), and finally, dinoflagellates (0.47%). The diversity index (H') ranged from 0.07 to 1.04 bits·cell–1, with the highest indices observed at stations closer to the glacier fronts and the one closest to the coast (<3 km). Based on phytoplankton community composition, 3 clusters were identified: (1) the station closest to the coast, (2) stations located between 0.66 and 1.12 km from the glacier front, and (3) stations between 2.61 and 11.10 km from the glacier front. Overall, diversity exhibited a fourth-degree polynomial relationship (R2 = 0.35) with glacier distance. Therefore, it can be concluded that the composition of marine phytoplankton varies based on its proximity to glaciers in Admiralty Bay.