The study, which is the culmination of Dr Emily Broadwell's intrepid polar and alpine adventures as part of her PhD in Physical Geography, sheds surprising new light on how glacier ecosystems respond to rising global temperatures.
Her journey to Signy Island, which is 370 miles from the Antarctic peninsula and 800 miles from the Falkland Islands, took two weeks and saw her navigate the daunting Drake's Passage, where ocean waves can reach 60ft.
Although Signy is renowned for its penguin and seal colonies, Emily's mission was to probe how snow and glacier algae survive and adapt in an environment of extreme low temperatures, abundant light and scarce nutrients.
Dr Broadwell, who is now a postdoctoral researcher in Environmental Microbiology at Aarhus University in Denmark, brought back algae samples from the three-mile by four-mile island to the MicroLab@Bristol at Bristol's Cabot Institute for the Environment for detailed analysis of its DNA alongside other samples collected in the Arctic and the Alps.
She said: "These landscapes are changing fast, and arctic and alpine glaciers might be some of the first habitats lost completely to climate change. Our work identified a novel form of the glacier alga called Ancylonema that has never been recorded in the Northern Hemisphere.
"The research also uncovered a surprisingly rich and habitat-specific diversity of both snow and glacier algal species. Different ice surfaces and snowpacks hosted unique algal communities. Notably, we found red snow algae dominating the ice cap, where Ancylonema glacier algae would normally be expected to prevail."
The findings challenge the assumption that Antarctic glacier ecosystems will respond uniformly to global warming. Results also indicate that as temperatures rise and melt seasons lengthen, future algal blooms in this region may not follow the same trajectory as the more widely studied Greenland Ice Sheet, which regularly experiences large-scale glacier algal blooms.
Dr Broadwell was based at the British Antarctic Survey research station for her three-month expedition, where temperatures were surprisingly mild (around 0°C) for the Antarctic summer. She then spent two weeks on board the research vessel RRS Sir David Attenborough on her return.
She said: "Fieldwork is always daunting, and even more so for somewhere as remote as Signy Island. I forgot all that once I got there though, the amazing landscapes and wildlife make the island a truly magical place. I even managed to set up a sourdough starter in the station that is still going strong!"
"Different types of snow and ice supported distinct algal communities, with the island hosting rarely observed ecological niches. These algae play an important role as the primary producers in Antarctic ecosystems and highlight how much there is still to learn about life in these cold, remote environments."
Study co-author Dr Chris Williamson, Associate Professor in Polar Microbiology at the University of Bristol, added: "The hidden diversity discovered in the snow and glacier algae from this remote Antarctic Island highlights how we need many more expeditions to sample further, in particular around the southern hemisphere. These findings are exciting and there is much more potential to expand our knowledge on the diversity and distribution of these unique microbes."
Paper
'Remote Antarctic Island Reveals Unique Algal Dynamics in Snow and Ice' by Emily L.M Broadwell et al. in ISME Communications New Developments in Microbial Ecology
