Scuba-diving scientists have began on an ambitious underwater survey of one of the largest intact kelp forests on the planet to discover the biodiversity that exists there.

The Patagonia Megatransect will span 1,200km, from the Gulf of Corcovado to Cape Horn off the coast of Chilean Patagonia, home to previously undocumented biological riches. 

The giant kelp (Macrocystis pyrifera) marine ecosystem represents an important natural carbon sink, which is key to climate stability and marine biodiversity. But the kelp forests are also facing threats, such as the plumose anemone (Metridium senile), an invasive species whose rapid advancement is decimating kelp habitats.

Kelp forests have been reduced by up to 90% in some parts of the world. It’s hoped that documenting the life that exists beneath Chile’s waves will support environmental protection efforts. 

“These kelp forests are key components of the planet’s coastal ecosystems that provide a wide variety of ecosystem services, including coastal protection, resource provision, biodiversity and climate regulation,” says Mathias Hüne, director of the Marine Program at Rewilding Chile, who’s leading the team of researchers, including experts from Austral University (Chile), University of Victoria (Canada), Southern Scientific Research Center (Argentina) and the University of Western Australia. 

“Kelp forests support 70–80 per cent of global fisheries, as various species complete part of their life cycle there, such as the king crab fishery in Southern Patagonia, where the species reproduces in kelp forests,” adds Hüne.

“In the fight against climate change,” continues Hüne, “they absorb 20 times more carbon than terrestrial forests, thanks to their extraordinary growth rate, which is unmatched by any other living organism on the planet. The giant kelp Macrocystis pyrifera can grow up to 50cm per day under optimal conditions. Giant kelp constitutes large-scale, extensive carbon sinks, most of which are found in Chilean Patagonia.” 

By measuring the precise capacity, the new data could help position Chile as a leading planetary reservoir of ‘blue carbon’.

The team began work in January 2026 and have completed the first phase of the project, which will run until March 2027.

In total, they’ll be conducting underwater studies over the course of six expeditions, taking in 90 sampling dive sites and 180 scientific transects, using over 7,200 underwater photo quadrants to survey diverse ecosystems ranging from the channels and fjords surrounding the glaciers, to islands out in the open ocean.

They’ll be using advanced technology to record underwater biodiversity, such as environmental DNA.

Scientists are already processing the gathered data, cataloguing species and identifying biodiversity hotspots. The findings will be published in scientific journals and made available through the Global Biodiversity Information Facility (GBIF), administered in Chile by the Ministry of the Environment. 

They have also recorded the disappearance of a kelp forest documented with satellite imagery only two years ago. 

Protecting the valuable ecosystems is seen as a race against time. In the region of Magallanes, artisanal fishermen have already proposed a 10-year fishing ban to protect kelp forests, which offer essential habitat for sea urchins, king crabs and scallops.

The research work is complex and challenging, operating in areas that are remote and difficult to access, while contending with Patagonia’s extreme weather conditions.

“We’ll visit unexplored sites previously visited only by Charles Darwin and, in modern times (1972), by the American ecologist Paul Dayton,” says Hüne. “In this context, the possibility of making new species records is not surprising. 

“Regarding the giant Macrocystis pyrifera kelp forests in Patagonia, reports indicate the presence of more than 300 associated marine invertebrate species, such as the red urchin (Loxechinus albus), the southern scallop (Austrochlamys natans), the snow crab (Paralomis granulosa) and egg masses of the Patagonian squid (Doryteuthis gahi), confirming their role as keystone species that structure ecosystems.

“Many of these species depend exclusively on the kelp forest, while others spend part of their life cycle there.

“All of this motivates us to continue gathering information on the biodiversity present in Patagonia’s kelp forests, especially in a vast and diverse region that is home to the most resilient kelp forest ecosystems on the planet,” concludes Hüne.

Top image: Kelp forest in Patagonia. Credit: Eduardo Sorensen/Rewilding Chile

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