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Its small dimensions are not an obstacle to their distribution on the planet. They are part of the zooplankton in marine and freshwater environments, in addition to playing a fundamental role in the food chain and to indicate environmental changes. 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 the Environment has published the archives of 14 species of copepods of the genus Boeckella living in Chilean and Argentine Patagonia, in the sub-Antarctic islands and in Antarctica. The work was prepared by scientists from the Institute of Ecology and Biodiversity (IEB), the University of Chile, the University of Magallanes, Costa Humboldt and the British Antarctic Survey (United Kingdom), to facilitate research and to democratize access to data on unexplored freshwater biodiversity.
"The terrestrial or freshwater fauna of Antarctica is very rare and reduced compared to marine biodiversity because there are no mammals, amphibians or reptiles and there is only one species of bird, and many believe that the whole continent is frozen but have the greatest diversity of liquid water systems, such as fjords, the lakes, among others, in which the copepods live ", says Claudia Maturana, a scientist at the Institute of Ecology and Biodiversity, who receives support from CONICYT and the Chilean Antarctic Institute for her investigation.
While Magellanic and Antarctic lakes they are usually oligotrophic, that is to say that they have few nutrients, they also differ from each other.
While in Patagonia, there is a greater wealth of Boeckella species, only the Boeckella poppei is found on the white continent. It is precisely this latter species that has aroused the interest of scientists to be the only invertebrate present in the lakes of continental Antarctica, the Antarctic Peninsula and the sub-Antarctic islands.
"Although there are other copepods of fresh water on the white continent, Boeckella poppei is the only crustacean to have such a presence on this territory "explains Maturana, who exhibited some of this work a few days ago at the Natural History Museum in London.
Among the main characteristics of these animals, there is their great resistance and adaptability. To get an idea, this arthropod has an intense red color that protects it from UV rays and inhabits deep, deep lakes that connect to marine waters or in smaller, shallower ecosystems that feed on ice melt. at temperatures below 5 ° C and even below 0 ° C.
"This animal can remain in a state of the egg for many years, as if it had hibernated, to survive in extreme conditions.In winter, for example, the Antarctic lakes freeze. To survive, you can go deep or reduce your metabolism. "
The IEB researcher added: "In 2012, a team of Chinese scientists analyzed the sediments of a lagoon near its Antarctic base and detected viable eggs of Boeckella poppei, 100 years old and older. able to hatch at any time ".
Dragged by the whaling industry?
Currently, one of the big questions is how Boeckella poppei has become one of the few representatives of terrestrial and freshwater wildlife in Antarctica.
"There is no certainty about what happened when the continent passed through the last Great Ice Age more than 20,000 years ago, while some say that everything has been extinguished, others believe that some species have survived with the help of shelters, "explains Maturana.
Given its wide distribution in Antarctica, Boeckella poppei is a model for testing the two previous hypotheses.
The big question is whether this copepod colonized the most southerly continent of the Earth since Patagonia sub-Antarctic islands, or if it manages to survive by taking refuge in remote areas during glacial periods and climatic changes over millennia.
Although there is a link between populations of Boeckella poppei from Antarctica and Patagonia, it is not very recent, as it would exceed 20,000 years. In any case, the way in which these organisms move has not yet been clarified. Some of the possible explanations suggest that seabirds traveling between the two continents could become vectors during the movement of these crustaceans.
Another possible mechanism would come to the pinnacle of the whaling industry in the nineteenth century. The crew of ships extracted freshwater Antarctic lagoons, which were stored in barrels for consumption and for other purposes. Therefore, when transporting or emptying containers with liquid, cetacean hunters were able to move the copepods to places where they had never been before.
However, none of these theories has been proven.
"Antarctic copepod populations remain very blank and little intervention. We have not detected greater human impact, "says the scientist.
Despite its obvious attributes of "super-crustaceans", there is no clear idea of the mechanisms of differentiation and adaptation to the different ecosystems in which it lives. An example is that some people have experienced a reduction in their size and fertility of females, in response to reduced availability of resources on the Antarctic continent.
"Although the role of these animals has been studied as a sentinel of climate change or as an indicator of water quality, research on evolutionary models of freshwater fauna has been little explored. That's why it's important to generate and provide information from Chile to learn about freshwater biodiversity at high latitudes, "Maturana.
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