Marine Plankton face threat of extinction as planet warms

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Census of marine plankton fossils reveals inability to adapt to large shifts in climate
Marine plankton—the foundation of many marine ecosystems, producers of about half of the oxygen we breath, and regulators of carbon dioxide in our atmosphere—may be at risk of extinction as our planet continues to warm, according to a study led by Ph.D. candidate Sarah Trubovitz and published in the journal Nature Communications. Plankton living in the world's coldest waters surrounding Antarctica, the Southern Ocean, are at highest risk of disappearing as temperatures rise. In an investigation of an abundant group of microscopic plankton called radiolarians and their reaction to temperature shifts during the Neogene period several million years ago, it was discovered that large changes in temperature led to dramatic decreases in polar radiolarian biodiversity. Trubovitz's findings contradict previous assumptions that marine plankton did and would migrate to follow favorable climate conditions in the event of large temperature shifts, instead confirming extinction as a more likely response. The implications of this research for marine plankton in our rapidly warming climate are dire.

"There are approximately 100 radiolarian species currently living and adapted to cold conditions in the Southern Ocean, many of which will be unable to survive as the climate continues to warm," Trubovitz said. "The extinction of these radiolarians alone will significantly lower the biodiversity of high-latitude ocean ecosystems. Furthermore, the amount of warming projected in the next 300 years is comparable to the amount of cooling that occurred at high latitudes over the last 10 million years. Since change is happening at such a rapid rate, there will not be time for evolutionary processes, such as the origination of new species, to offset extinction. We don't know enough about ecological interactions between plankton species to say exactly what will happen, but we should anticipate some cascading effects throughout the marine foodweb if a significant number of radiolarian species…
Jennifer Theresa Kent
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