Wednesday , September 28 2022

The unknown freshwater inhabitants revealing the secrets of Antarctica and Patagonia – Mundoacuicola


A group of crustaceans inhabits almost all aquatic ecosystems and has attracted attention from Chilean scientists (Mundo Acuícola).

The copepodes, or called "super-crustaceans", surprise their high resistance and adaptability to extreme environments. Today they provide clues about the white continent's scarce land and freshwater fin and its connection to South America.

Its small dimensions are not an obstacle to distribution worldwide. They are included in zooplankton in marine and freshwater environments, except that they fulfill a fundamental role in the food chain and indicate environmental changes. It is a group of crustaceans that live in almost all aquatic ecosystems and have caught the attention of Chilean scientists.

For this reason, the Ministry of the Environment published information about 14 species of copepods of the genus Boeckella, living in Chilean and Argentinean patagonia, in the subantarctic islands and in the Antarctic. 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.

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

While in Patagonia there is a greater wealth of Boeckella species, only the white continent exists Boeckella poppei. 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 It is the only crustacean animal that has so much presence in this territory, explains Maturana, who explained a few of this work a few days ago 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 scientist adds: "In 2012, a team of Chinese researchers analyzed sediment from a lagoon near its Antarctica base and discovered feasible eggs from Boeckella poppei, who was 100 years old and could hatch at any time. "

Pulled by the whaling industry?

Currently, one of the big questions is how Boeckella poppei He 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.

Given its extensive distribution in the Antarctica, Boeckella poppei It is a model for testing the two previous hypotheses.

The big question is whether this corpshead colonized the southernmost continent of the earth from the patagonian or sub-arctic 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.

While there is a link between populations of Boeckella poppei of Antarctica and Patagonia, it would not be very recent as it would exceed 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. "The population of the Antarctica poles remains very untouched and small interventions. We have not discovered a greater degree of human impact," said 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 women's fecundity in response to a lower supply of 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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