Published on January 24, 2019
The times of intense climate change trigger the evolution of new species. The marine depths, the largest ecosystem on the planet, is an ancient ark of relics from the dinosaur era, where "living fossils" exist while new species are evolving rapidly. New research shows that the evolution of new species is highest in the coldest region on Earth, Antarctica, whose waters are still recovering from the extinction events of tens of millions of years ago, when the ice sheets They began to dominate and the water temperatures plummeted.
On the contrary, although the diversity in the deep tropical seas (at more than 200 meters) is high, it is not an environment that produces new species quickly, but accumulates its rich biodiversity for millions of years. The deep tropical seas are a refuge for ancient fauna or "living fossils", mainly due to relatively stable conditions over time.
"Unknown territory": new species evolve during epic climate change
New research, published in Nature, reverses previous theories about how the amazing biodiversity of the oceans evolved, with important implications for conservation. The study, entitled "Contrasting processes lead to opiuroid philodiversity through shallow and deep sea beds", was led by the first author, Dr. Tim O'Hara, chief curator of marine invertebrates at Museums Victoria. The article published in Nature reverses the ideas on oceanic biodiversity.
The Sloane viper fish shown above is an alien species that lives in the deep ocean, instead of deep space. Image of David Paul.
Biologists have long speculated that evolution is accelerated by relatively high tropical temperatures, with slower development in colder and deeper waters. However, this research finds that evolution does not follow a course, but depends on the geological, climatic and biological history of each ecosystem. Evolution proceeded differently in shallow and deep seas.
To study patterns of evolution in the world's oceans, the team focused on the evolution of "deep-sea fragile stars" (Ophiuroidea). These strange spiny echinoderms with a typically circular body and five long flexible arms abound on the sea floor worldwide. Although they will not be familiar to many, their abundance makes them the perfect group to study large-scale patterns of how marine life arose and spread throughout the planet.
"Report of the planet Earth": images of creatures from unexplored depths in Antarctica ("2018 the most seen")
The researchers used the data collected in the pioneering "Sampling to the Abyss" trip of 2017 aboard the research vessel "Investigator" of the National Marine Facility of CSIRO (below), directed by Museums Victoria. The month-long expedition explored the abysmal depths of the ocean on the east coast of Australia for the first time. Dr. O'Hara was the Chief Scientist on the trip, and this publication is the first important article to be published as a result of the trip.
The DNA was used to reconstruct a complete picture of how fragile stars have evolved across the Indian and Pacific oceans in the southern hemisphere. Dr. O'Hara explained: "Museum collections are a treasure trove of preserved biodiversity collected from thousands of scientific expeditions. DNA sequencing from these specimens can unlock the history of life on our planet. "The digitization and DNA sequencing of museum collections offers a new way of seeing how life has evolved and spread throughout the world."
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These deep-water Antarctic environments require as much protection as the most famous and familiar habitats, such as coral reefs and mangroves. However, the lack of knowledge about marine life in these dark waters has made clear the best way to protect and preserve these environments from human exploitation, such as fishing or deep-sea mining.
The document by Dr. O'Hara and his team is the result of what he expects to be the first stage of a global project to shed more light on the processes of evolution in the precious deepwater environments, and how we can project them better.
The Daily Galaxy through CSIROScope and Museums Victoria
Image credit at the top of the page: thanks to Netflix Our Planet