Patagonian kelp constantly adapting to deal with climate change, study finds

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Photo: Eduardo SorensenPhoto: Eduardo Sorensen
By Tomás Moggia
Translation by Patrick Nixon
Over the last 50 years, climate change has been responsible for an estimated 38 percent worldwide decline in giant brown algae (kelp) (Macrocystis pyrifera) forests. However, the unique climatic conditions in the fjords and channels of Chilean Patagonia's fragmented coastline have made this part of the world one of the last great refuges for this species, which is also known in Chile as huiro or calabacillo.
Due in part to its amazing growth rate, which under optimal conditions can reach 5 perent per day, the kelp can form large underwater forests that fulfill a vital ecological role in the ecosystem, either as part of the trophic chain or serving as a place of refuge and reproduction for various organisms.
Taking as an example the Yendegaia fjord, located in the Beagle Channel, in the Magallanes region, a group of scientists carried out research to physiologically characterize the kelp forests and understand how they are dealing with climate change.
A recent research paper entitled "Photobiology of the giant kelp Macrocystis pyrifera in the land-terminating glacier fjord Yendegaia (Tierra del Fuego): A look into the future?" was recently published in the scientific journal Science of the Total Environment. Read the study here.
Following analysis carried out in the field – with the Stoppani glacier calving in the background – and in the laboratory, the team of researchers from the Center for Dynamic Research on High Latitude Marine Ecosystems (IDEAL) of Chile's Austral University (UACh) concluded that kelp forests create a unique acclimation strategy in the face of new environmental variables caused by global warming. Among these is the scarcity of light due to stress factors such as greater water turbidity and high levels of particulate material, which have led species to optimize the amount of available light they capture to carry out photosynthesis.
Photo: Eduardo SorensenPhoto: Eduardo Sorensen
“The Yendegaia fjord is currently showing us what will happen to other types of glaciers in Patagonia in the future. The outlook we have today is possibly the same as what we will have in 30 years, taking into consideration the most pessimistic future scenarios of climate change. Despite everything, the algae will still be there," says Mauricio Palacios, author of the study.
Using chemical analysis and transmission electron microscopy, scientists observed that the samples collected in Yendegaia contained an abundant presence of anti-stress phenolic compounds called phlorotannins, which would make it possible to cope with ultraviolet radiation, temperature and the presence of herbivore invertebrates, demonstrating that the algae constantly adapts to changing environmental conditions.
It is thought that as the glaciers retreat, new areas of the seabed will emerge that may be colonized by these macroalgae, which could expand their presence. This would have an impact on biodiversity of Patagonian fjords and channels given that the underwater kelp forests are home to one of the most productive ecosystems on the planet.

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