Saturday , October 1 2022

Copepods: the unknown inhabitants of the Antarctic rivers and lakes revealing their secret technology



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Its small size does not constitute an impediment to their distribution on the planet. They are part of the zooplancton in marine and sweet environments, in addition to fulfilling a fundamental role in the food chain and indicating environmental change. We refer to copepods, a group of crustaceans that live in almost all aquatic ecosystems and have monopolized the attention of Chilean researchers.

For this reason, the Ministry of Environment has published the dossiers 14 species of the genus Boeckella that live in Patagonia Chile and Argentina, in the sub-Antarctic and Antarctic islands. The paper was developed by researchers from the Institute of Ecology and Biodiversity (IEB), University of Chile, University of Magallanes, Costa Humboldt and British Antarctic Survey (UK) to facilitate research and democratization of access to data on Biodiversity exploration of sweet water.

"Terrestrial or fresh fauna in Antarctica is very small and small compared to marine biodiversity because there are no mammals, amphibians or reptiles, and there is only one species of bird. In addition, many believe the whole continent is frozen but has the highest "said Claudia Maturana, a researcher at the Institute of Ecology and Biodiversity, receives the support of CONICYT and the Antarctic Institute of Chile for its investigation.

While the Magellan and Antarctic lakes they are usually oligotrophic, that is, they have few nutrients, they also differ from one another.

Claudia Maturana
Claudia Maturana

While in Patagonia there is a greater wealth of Boeckella species, only Boeckella poppe is found on the white continent. This very species has provoked the interest of scientists as the only invertebrates present in the continental Antarctic lakes, the Antarctic peninsula and the sub-Antarctic islands.

"While there are other fresh water copepods on the white continent, Boeckella poppei is the only crustacean that has such a large presence on this territory "explains Maturana, who presented part of this paper a few days ago at the Museum of Natural History in London.

Among the main characteristics of these animals are their high resistance and adaptability. To get an idea, this arthropod has an intense red color that protects it from UV rays and lives in deep and deep lakes that connect with marine waters or in smaller and less deep ecosystems that feed on ice melting at temperatures below 5 ° C and even below 0 ° C.

"This animal can remain in a state of eggs for many years, as if it were hibernating, to survive the extreme conditions. In winter, for example, the Antarctic freezing lakes, after which to survive, you can go to the depths or you can lower your metabolic rate. "

The IEB researcher adds: "In 2012, a team of Chinese scientists analyzed the sediments from a lagoon near its Antarctic base and detected viable Boeckella Poppe eggs, who were 100 years old and could handle at any time" .

Drawn by the whaling industry?

Currently, one of the big questions is how Boeckella Poppa has become one of the few representatives of the Antarctic terrestrial and Danube fauna.

"There is no certainty about what happened when the continent passed through the last great glaciation more than 20,000 years ago. While some point out that everything has been extinguished, others believe that some species have survived with help shelters, "says Maturana.

Sebastian Rosenfeld
Sebastian Rosenfeld

Given its extensive distribution in the Antarctic, Boeckella Poppa is a model to test the two previous hypotheses.

The big question is whether this the copepod colonized the southernmost continent of the Earth of Patagonia or the sub-Antarctic islands, or whether it managed to survive through shelter in isolated places during glacial periods and climate change during the millennia.

Although there is a link between the Poplar Boeckella poppies in Antarctica and Patagonia, this would not be very recent as it would be over 20,000 years. In any case, it has not yet been clarified how these organisms move. Some possible explanations suggest that seabirds traveling between the two continents can become vectors when moving these crustaceans.

Another possible mechanism would come in the glory of the whaling industry in the nineteenth century. The ship's crew extracted fresh water from the Antarctic lagoons, which was stored in barrels for consumption and other uses. Therefore, when transporting or emptying liquid containers, cetacean hunters were able to move their copepods to places where they were not.

However, none of these theories has been proven.

Claudia Maturana
Claudia Maturana

"The antropic populations of the copepod remain very much pure intervention. We have not detected a greater degree of human impact, "the scientist points out.

Despite its obvious "super-crustacee" attributes, there is no clear idea of ​​the mechanisms of differentiation and adaptation to the different ecosystems in which it lives. An example of this is that some individuals have experienced a reduction in body size and a fecundity of females in response to the low availability of resources on the Antarctic continent.

"Although the role of these animals has been studied as sentinels of climate change or as indicators of water quality, the research of the evolutionary models of freshwater fauna has been little explored. It is therefore important to generate and provide information from Chile to learn more about the biodiversity of sweet waters in large latitudes, "Maturana.

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