How a starfish can help us understand climate change

A small starfish living in Norwegian waters is changing with the climate and is being studied to better understand the impact of global warming.

The Norwegian Sea, part of the North Atlantic Ocean, isn’t particularly inviting for a swim, given its low temperatures. However, it is the ideal habitat for a type of starfish that looks just like a cookie-cutter, so much so that its name is: the cookie-cutter seastar. Scientifically known as Ctenodiscus crispatus, its friendly shape isn’t its only peculiarity. This curious marine animal is in fact a veritable sentinel of climate change, to the point of having become the object of study of a passionate team of scientists.

star fish
Given that the oceans are accumulating much of the excess heat released on Earth, studying their species, such as starfish, is very useful to understanding global warming trends © Morris MacMatzen/Getty Images

The star (fish) observed under a microscope

The research group, which includes Irene Zanette of the University of Southampton, in the UK is led by Canadian physicist Pierre Thibault, who teaches at the University of Trieste, in Italy. An expert in X-ray analysis techniques, he uses the Elettra synchrotron, a particle accelerator, as a powerful microscope with which he obtains “a lot of biological data on the reproductive and digestive organs of these organisms and on how they’re able to adapt to climate change”.

For the first time, mutations within starfish – which respond to climate mutations – were observed directly in intact samples and stored in ethanol. The samples were provided by the National Oceanography Centre Southampton’s Christina Wood. The images obtained by the synchrotron are in high quality and don’t present distortions.

Starfish, ocean superheroes

Studying the oceans, and consequently their species, is crucial to understanding the severity of global warming. In fact, oceans absorb more than 90 per cent of excess heat on Earth. They also accumulate large amounts of carbon dioxide, which lowers the ocean’s pH, causing a phenomenon known as ocean acidification which has major repercussions on biodiversity, including starfish. Not to mention that the melting of glaciers – in the case of the Norwegian Sea, Greenland and the Canadian islands’ glaciers in particular – is pouring large amounts of fresh water into the oceans, profoundly altering ecosystems.

Starfish in the shape of a cookie-cutter are trying to respond quickly and effectively to all of these variables. So observing them means, on the one hand, understanding how drastic the changes are, and on the other hand, how marine fauna is reacting. These particular starfish also play an important role in capturing carbon – and are real superheroes of the sea.

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