While on most of the planet these species struggle to survive the effects of global warming, a new study published in the renowned Journal of Geophysical Research-Oceans reveals that the southern tip of the American continent offers a true place of protection to these giant algae.

When the marine geographer Alejandra Mora-Soto began investigating the warm sea surface temperature events of western Patagonia, she did not imagine that she would discover something that was not described in the scientific literature. While reviewing the thermal anomalies of the fjords and channels of the extreme south of the American continent, she realized that in the last ten years there have been more cold waves in the sea than in the previous decades.

That finding was the starting point for a study published today in the prestigious Journal of Geophysical Research-Oceans that suggests that the marine forests of giant algae in southern Chile have been maintained with sea surface temperatures that are benign for their reproduction and growth.

To carry out the research, the team of marine biologists, geographers and oceanographers took ten geographical units as study area, ranging from the Gulf of Penas to Cape Horn. The researchers analyzed data from 1982 to 2020 and identified that between 2014 and 2018 extreme cold events occurred near the shores of Cape Horn, the western entrances of the Strait of Magellan, and the Beagle Channel.

“These rapid and localized cooling could be explained by two reasons. The first of these is that the melting of glaciers generates the entry of cold water into the systems. The second has to do with changes in the wind pattern that would alter the thermal flow of the ocean,” says Mora-Soto, PhD in Geography from the University of Oxford (UK,) postdoctoral fellow at the University of Victoria (Canada) and study leader.

These events, which are isolated at the moment, are accompanied by temperatures that allow marine forests to maintain comfortable temperatures, which is considered unprecedented compared to other marine forests in the world.

“What is interesting about this result is that contrary to the global trend towards a greater frequency of marine heat waves, signs of an increase in cooling pulses have been detected in the Chilean Patagonia region in recent years. The next question is whether these cold waves will alter the temperature regime that the southern marine ecosystem is experiencing and the potential consequences on its structure and function,” says José Luis Iriarte, doctor in oceanography and researcher at the IDEAL Center of the Austral University of Chile (UACh) and co-author of the study.

Marine forests fulfill an important ecological function: they provide shelter, food and are breeding sites for countless marine organisms and species. © Ignacio Garrido

A shelter that has to be protected

Marine forests fulfill an important ecological function: they provide shelter, food and are breeding sites for countless marine organisms and species. They are considered among the most productive ecosystems in the world and, despite being widely distributed, in some places on the planet they have completely disappeared.

In Patagonia, most of the land surrounding the marine forests is protected, but not necessarily the waters. In central and northern Chile, it is estimated that 2% of these ecosystems are lost each year.

“In the north of Chile, great damage has been done to these ecosystems as a result of indiscriminate extraction. Not only the algae that compose them are being lost, but also all the associated biodiversity and the services that these environments provide. We must protect the marine forests of Patagonia that have remained intact for hundreds of years and that, given the temperature values found in this study, have favorable conditions to reproduce and grow without inconveniences,” concludes Erasmo Macaya, doctor in Marine Biology, academic from the University of Concepción (UdeC), researcher at the IDEAL Center and co-author of the study.

To review the study, click here.