Ecological and habitat preferences of diatoms in lakes of Lützow‐Holm Bay, East Antarctica

Abstract Lakes and ponds along the Antarctic coastline provide an opportunity for palaeoclimate reconstructions to complement ice core records from the interior of the continent, including via their diatom records. Diatom palaeoecological studies in remote Antarctica are partially undermined by uncertainty concerning the relative influence of climate, water quality and substrate on diatom species assemblages. The relative abundance and distribution of diatoms across a range of substrates and water depths were analysed from nine lakes in the coastal ice‐free regions of Lützow‐Holm Bay, East Antarctica. Specific conductivity and sample position (whether from the shallow, littoral zone, or from deeper parts of the lake) were identified as significant variables in explaining diatom distribution, using non‐metric multidimensional scaling and regression tree analysis to identify statistically significant groupings of diatom assemblages and associated environmental variables. In contrast to the significant difference between the diatom assemblages from the shallow littoral region and the lake floor at most sites, the diatom flora from different substrates in the littoral zone were not significantly different, which may be related to the extent of ice cover. Humodophila australis was the most common species in the lakes with lowest specific conductivity, whereas Halamphora vyvermaniana was associated with lake‐floor habitats and Psammothidium papilio with samples from littoral zones at several sites. These observations hold significance for the interpretation of lake sediment diatom assemblages in Lützow‐Holm Bay as archives of past climate and indicate that sampling strategies should consider a range of locations in lakes, with samples from the lake floor prioritised for the interpretation of sediment core diatom records.