A study published in the journal Science of the Total Environment, managed to determine the composition and functional potential of microbial communities associated with snow algae in Fildes Bay, Doumer Island and O’Higgins Base, on the Antarctic Peninsula.
Daniela Jofré, IDEAL Center. The increase in global temperatures – as a consequence of climate change – has the potential to impact the biodiversity of Antarctica. According to various investigations, a greater occurrence and expansion of snow algae blooms is expected, microorganisms that stain this element in different colors (depending on the composition of species and their pigmentation,) and that have acquired a greater presence in the Antarctic Peninsula.
Although these blooms are not a recent phenomenon, information on the diversity of snow algae, their occurrence and what effects their presence is having, remains limited in the Antarctic territory. That is why a group of researchers led by Daniela Soto, biochemist at the Center for Dynamic Research on High Latitude Marine Ecosystems (IDEAL) of the Austral University of Chile (UACh), studied both the taxonomic composition and the cellular functions present in these communities.
The study compared the diversity and composition of snow algae blooms by sequencing amplicons (set of DNA molecules) at three different sites in Antarctica: Fildes Bay, Doumer Island, and O’Higgins Base. In addition, the scientists carried out a comparison between different colors of snow (green and red) in seasonal and semi-permanent snowfields. “Based on the presence of certain genes in metagenomes, one can get the idea of what functions microorganisms can perform in an ecosystem,” commented the researcher.
“The composition of prokaryotic and eukaryotic bacteria within microbial communities varied significantly between sites, colors, and semi-permanent snowbanks —associated with glaciers— or seasonal snow. However, at a functional level, the communities showed a profile similar and consistent with polar ecosystems,” explained Soto.
Regarding potential interactions, the results show that four large bacterial groups (Pedobacter, Polaromonas, Flavobacterium and Hymenobacter) presented the most frequent co-occurrence patterns in the sampled sites. However, thanks to the reconstruction of genomes from the metagenomes, it was determined that the bacteria within the snow algal blooms are likely to compete for resources rather than form cooperative communities with each other.
“We highlight the number of samples analyzed in a place like Antarctica, since there are very few studies that cover so many sites and have not previously carried out a functional characterization of the communities,” explained the researcher from the IDEAL Center.
“This study represents an important advance in the molecular and functional characterization of a variety of microorganisms that inhabit highly vulnerable ecosystems in the polar regions. Now we not only realize that they are much more diverse and abundant than we thought, but we are also beginning to understand their role in the physical, biological and chemical processes that occur in the Antarctic cryosphere,” explained Dr. Iván Gómez, researcher at the IDEAL Center and co-author of the study.
Researchers from the Institute of Marine and Limnological Sciences of the UACh and the Department of Earth and Environmental Sciences of the University of Milano-Bicocca, Italy, participated in the work that was published in the scientific journal Science of the Total Environment.
Read the study here.