Diversity patterns of surface water marine microorganisms in the Gerlache Strait (Antarctica)

X Simposio de Estudios Polares, 15-17 May 2024, Salamanca

Although microorganisms play a crucial role in marine ecosystems, their role in Antarctic biodiversity and biogeochemical cycles remains poorly understood. In this study, we describe the diversity patterns of microorganisms in Gerlache Strait, Antarctica (64°29’24’’ S; 62°20’24’’ W). The dataset included a north-south transect, and microbial diversity (including prokaryotes and eukaryotes) was determined by metabarcoding. Two main factors were considered a priori: ‘station’ (7 stations) and ‘size fraction’ (3 fractions). Total Diversity within each sample was defined by calculating the total number of species (Richness). Variation in community structure between samples was calculated as Bray-Curtis distances. The results showed that Richness had similar values along all size fractions and increased from north to south (reaching maximum values in the middle stations). Although two clusters were observed in the NMDS analysis, they did not correspond to the factor ‘station’ or ‘size fraction’. Concerning taxonomy, while prokaryotes were dominant in all samples, eukaryotes were very low abundant in the entire dataset. The most dominant prokaryotic phylum, present in all samples, was Proteobacteria (specifically the classes Alpha- and Gammaproteobacteria), followed by Bacteroidota. Eukaryotic photosynthetic groups were, in general, very low abundant. The Division Fungi was low abundant but was detected in most of the samples. This study will be completed by including more stations and depths (in total, 132 samples), which will allow us to describe changes in microbial diversity along the water column and also to analyze the effect of "freshening" (the release of freshwater from glaciers into seawater) on marine microbial communities

Peer reviewed