Climate Change To Affect Species Relations In Polar Regions, Say Scientists

(CORDIS) — Global warming will produce modifications in biological communities of polar regions, resulting in changes in the dominant species and the relations among them, according to a new study published by EU-funded researchers in the journal Nature Climate Change.

The study brings together scientists from Germany, New Zealand, Spain and the United Kingdom. It is supported by the EU-funded project ASSEMBLE (‘Association of European marine biological laboratories’), which received EUR 8.7 million of funding under the ‘Capacities’ Theme of the Seventh Framework Programme (FP7).

The researchers report that the temperature changes taking place in Antarctica and the Arctic as a result of climate change will bring about important changes in the cyanobacteria mats, the most important biological communities in the polar zones. These cyanobacteria mats cover large ice-free zones during the polar summer, thus modifying substantially the biogeochemical cycles in those zones.

As a result of these changes, the dominant species and the relations among them will also change: there will be an increase in toxin-producing species, and an increase in the exchanges of carbon and nitrogen among living and inert beings.

The study researchers carried out experiments with microbacteria mats, multilayered microbial communities dominated by cyanobacteria. These were obtained from Byers Peninsula, located at Livingston Isle, in the South Shetland Islands Archipelago, Antarctica.

The mats were preserved at different temperatures similar to those found in Antarctica and the Arctic over a six-month period. They also preserved mats at temperatures that could well be representative of what these regions might feel like in several decades’ time, according to climate change prediction models.

The findings show a striking change in the species dominating the mats. At lower temperatures, it seems that the dominant species disappear; at higher temperatures, this trend is reversed as diversity decreases, and the mats tend to destabilise.

If the mats were to disappear, so to would the microbial biological communities that inhabit them. These changes in the species might also impact the rest of the organisms in these microsystems: viruses, bacteria, and protozoa, who all feed on cyanobacteria.

The study also reports that when likewise tested at temperatures that could be representative of these regions in several decades’ time according to climate change prediction models, cyanobacteria dominating the macrobial mats begin to produce toxins such as microcystins, which could have devastating effects on several organisms.