Wednesday , September 28 2022

Copepods: the unknown inhabitants of Antarctica rivers and lakes revealing their secrets | technique



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Its small dimensions are not an obstacle to distribution worldwide. They are part of zopen plankton in marine and freshwater environments, in addition to fulfilling a fundamental role in the food chain and indicating environmental changes. We refer to copepods, a group of crustaceans living in almost all aquatic ecosystems, which have monopolized the attention of Chilean scientists.

For this reason, the Ministry of the Environment published a register of 14 species of copepods of the genus Boeckella living in Chilean and Argentinean patagonia, in the sub-arctic islands and Antarctica. The work has been developed by researchers from the Institute of Ecology and Biodiversity (IEB), University of Chile, the University of Magallanes, Costa Humboldt and the British Antarctic Survey (UK) to facilitate research and democratize access to data on the small explored freshwater biodiversity.

"Antarctic soil or freshwater fauna is very short and decreasing compared with marine biodiversity, as there are no mammals, amphibians or reptiles, and there is only one bird species. In addition, many believe that the whole continent is frozen but has the highest diversity of liquid water systems, such as fjords, lakes, among others where copepods live, says Claudia Maturana, researcher at the Institute of Ecology and Biodiversity, receiving support from CONICYT and the Chilean Antarctic Institute for its investigation.

While Magellanic and Antarctica lakes they are usually oligotrophic, that is, they have few nutrients, they also differ from each other.

Claudia Maturana
Claudia Maturana

While in Patagonia there is a greater wealth of Boeckella species, only Boeckella poppei is found on the white continent. It was precisely the last species that aroused the researchers' interest in being the only backbone in the lakes of the continental Antarctica, Antarctica Peninsula and the subantarctic islands.

"Although there are other freshwater scrambles on the white continent, Boeckella poppei is the only crustacean animal that has so much presence in this territory "explains Maturana, who a few days ago exhibited part of this work at the Natural History Museum in London.

Among the most important characteristics of these animals is their high resistance and adaptability. For an idea, this arthropod has an intense red dye that protects it from UV radiation and preserves extensive and deep lakes that connect with marine water or in lesser and grounded ecosystems that melt on ice melting at temperatures below 5 ° C, and even below 0 ° C.

"This animal can remain in egg condition for many years, as if it were driven, to survive extreme conditions. In winter, for example, the lakes in Antarctica can freeze, so you can go to the depths or lower your metabolism."

The IEB researcher added: "In 2012, a team of Chinese researchers analyzed sediment from a lagoon near its Antarctica base and discovered viable Boeckella poppei eggs, 100 years old and could hatch at any time."

Pulled by the whaling industry?

Currently, one of the big questions is how Boeckella Poppei became one of the few representatives of the Antarctic soil and freshwater fin.

"There is no certainty about what happened when the continent went through the last great ice age more than 20 thousand years ago. While some point out that everything was extinguished, others believed that some species survived with protection," said Maturana.

Sebastian Rosenfeld
Sebastian Rosenfeld

In view of its extensive distribution in Antarctica, Boeckella poppei represents a model to test the two previous hypotheses.

The big question is about this Copepod colonized the southernmost continent of the Earth from Patagonia or sub-Antarctic islands, or if it managed to survive by taking shelter in isolated places during the ice age and climate change that occurred over the millenniums.

Although there is a link between the populations of Antarctica and Patagonia poppies, it would not be very recent because it would be over 20,000 years. In any case, it has not been clarified how these organisms are moving. Some of the possible explanations indicate that sea birds traveling between the two continents can become vectors when they move these crustaceans.

Another possible mechanism would come to the flowering time of the whaling industry during the nineteenth century. The vessel's crew extracted freshwater from the Antarctic lagoons, which were stored in barrels for consumption and other uses. Therefore, when transporting or draining the containers with liquid, the cetacean owners could move the copepodes to places where they had not been previously.

But none of these theories have been proven.

Claudia Maturana
Claudia Maturana

"Antarctic copepod populations remain a lot untouched and small intervention. We have not discovered a greater degree of human impact, says the researcher.

Despite its obvious "super-crustaceans" properties, there is no clear perception of the differentiation and adaptation mechanisms of the various ecosystems in which it lives. An example of this is that some individuals have experienced a decrease in body size and fecundity of honor, in response to reduced access to resources on the Antarctic continent.

"Although the role of these animals has been studied as climate change or as indicators of water quality, research on freshwater fungus evolutionary patterns has been somewhat explored. That is why it is important to generate and provide information from Chile to learn more about biodiversity in freshwater in high latitudes ", Maturana.

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