Revisiting Potter Cove, King George Island, Antarctica, 12 years later: new observations of marine benthic diatoms

Continuous observations of Antarctic benthic diatoms are necessary to detect changes in species composition and biodiversity that may result from environmental changes. The present work provides a systematic list of benthic diatoms from Potter Cove (62.03 degrees S 58.35 degrees W) collected during summer 2015. The new findings are compared with observations made 12 years ago (summer 2003). In total, 80 taxa were found, similar to that encountered earlier, but 17 species (21% of the total species number) were not observed in 2003, and 26 species (31%) of those reported in 2003 did not appear in 2015. The dominant species in 2003 and 2015 was the large epipelic and cosmopolitan Gyrosigma fasciola. Most of the species either newly observed in the present study, or absent in the present study but observed previously, occurred either rarely or very rarely. Gyrosigma arcuatum and Pleurosigma diversestriatum were newly observed in 2015 and not previously reported from polar regions. This study provides systematic and ecological information on all taxa encountered and is illustrated with light microscopy and scanning electron microscopy (SEM) images. We emphasize that ice-inhabiting and other benthic diatoms should be included when considering the biodiversity of polar diatoms. Thus, we hope that the present study will add a piece to the puzzle of climate change effects on the benthic diatoms in this vulnerable region and will complement earlier published species records in the area.

Automated summary

Continuous observations of Antarctic benthic diatoms are essential for detecting changes in species composition and biodiversity due to environmental changes. This study provided a systematic list of benthic diatoms from Potter Cove in summer 2015, comparing new findings with observations from 2003. The dominant species remained the same over the 12-year period, but significant changes were observed in the presence of certain species.