Scientists isolated a snow alga collected from the Collins Glacier on King George Island. After integrating various analyzes, they found a surprising scenario: The specimen had not been described. The research, led by marine biologist Francisca Elizabeth Gálvez, was published in the journal Frontiers in Plant Science.
Andrea Navarro, IDEAL Center. Snow algae are microscopic organisms that can cover large areas in the alpine and polar regions. The pigments they possess generate a macroscopic phenomenon of colorations capable of dyeing the snow in gradients from green to red. In cold ecosystems, they play a crucial role, which is just being glimpsed.
They are considered true sensors of climate change, because due to their colorations they are capable of reducing solar reflection on snow (a phenomenon known as albedo) and, therefore, accelerating the melting of snow with important consequences for the climate. In ecological terms, they are the basis of diverse microbial and microinvertebrate communities. In addition, after the arrival of summer they can actively fix carbon, so much of the primary productivity of glaciers and snowfields has been attributed to snow algae.
Despite its scientific importance, many aspects related to its biology, adaptations and especially its diversity are unknown. To help fill this information gap, a study by the IDEAL Center of the Austral University of Chile (UACh) focused on analyzing the biodiversity of these tiny organisms that inhabit the Antarctic peninsula. The study is part of a project of the Chilean Antarctic Institute (INACh) of the marine biologist and UACh doctorate, Francisca Elizabeth Gálvez.
To improve the identification and characterization of snow algae from colored snow, the researchers used a polyphasic approach that considered microscopy, taxonomy, physiology, and transcriptomics. After the integration of these different disciplines, the scientists managed to describe a new genus, Chlorominima, with the type of species Chlorominima collina, which was named in that way since the analyzed sample was collected from the Collins Glacier (King George Island,), in the Maritime Antarctic region.
To carry out the study, Gálvez isolated the microalgae and then observed it using light and electron microscopy. Subsequently, molecular analyzes confirmed that the isolated alga did not belong to Chloromonas, a typical genus of snow and that, therefore, it forms an independent lineage, which is closely related to other Antarctic and Arctic strains not yet identified.
“This new strain presents some morphological characteristics similar to Chloromonas, such as the lack of pyrenoid, the presence of the parental cell wall in the daughter cells and the presence of two flagella, but it differs from this genus due to the unusual position of the nucleus, the chloroplast shape, the number of vacuoles and the small size of the cells,” explains Gálvez. “Before, with the naked eye of a microscope, it was thought that everything was the same and now, thanks to molecular advances, we realize that there is a distinction that we were not aware of,” she adds.
In addition, thanks to this research, it was possible to observe that the new species has psychrophilic characteristics, typical of snow algae, which correspond to the presence of several genes related to protection against cold. This makes it possible to identify a series of adaptations that these organisms present to the snow environment.
“This study contributes to the knowledge of the biodiversity of the Antarctic marine flora. We are just discovering how diverse the snow algae of the white continent are and, in that sense, this new species and genus completely change the scenario of what we knew until now,” explains Dr. Iván Gómez, deputy director of the IDEAL Center, academic of the Institute of Marine and Limnological Sciences (ICML) and co-author of the research.
Currently the strain is deposited in the Culture Collection of Algae and Protozoa (CCAP) in Scotland, under the code Chlorominima collina 6/1.