Photo: Diego Ramos for Rewilding Chile
Discoveries of the Patagonian Megatransect: Chile’s vast kelp forests promise climate refuge with a warning
With the support of national and international organizations, nonprofit Rewilding Chile is surveying one of the largest intact kelp forests on the planet, home to previously undocumented biological treasures. This vital marine ecosystem represents a powerful natural carbon sink which is key to climate stability and marine biodiversity, but also facing emerging threats.
An interdisciplinary team led by Rewilding Chile has completed the first phase of the Patagonia Megatransect, an ambitious multi-stage underwater journey spanning 1,200km from the Gulf of Corcovado to Cape Horn, to document one of the planet’s largest intact kelp forests using advanced new technology in order to advocate for their protection.
The expedition ventures into a little-known ecosystem of monumental scale: the forests of Macrocystis pyrifera, giant kelp that reach up to 80 meters. One of Earth’s most efficient natural carbon sinks, they are able to absorb up to 20 times the amount of carbon as forests on land. By measuring their precise capacity, the new data could position Chile as a leading planetary reservoir of blue carbon.
“Our initial findings show that Patagonia’s fjords and channels remain a global climate refuge for kelp forests, which on a planetary scale have been reduced by up to 90% in some regions,” says Mathias Hüne, Director of the Marine Program at Rewilding Chile. Hüne also cautions, “We also found urgent threats, including plumose anemone (Metridium senile), an invasive species whose rapid advancement is decimating kelp habitats, and recorded the disappearance of a kelp forest documented with satellite imagery only two years ago. Now we’re effectively in a race against time to protect these valuable ecosystems.”
Between January 2026 and March 2027, the scientific team will be conducting underwater campaigns over the course of six expeditions. The project features 90 sampling sites and 180 scientific transects, using over 7,200 underwater photo quadrants to survey diverse ecosystems that range from the channels and fjords surrounding the glaciers to islands out in the open ocean.
Using advanced technology to record underwater biodiversity, such as environmental DNA and underwater photo quadrants, scientists are already processing data, cataloging species and identifying biodiversity hotspots essential to marine health and the local fishing economy. In the region of Magallanes, artisanal fishermen have already proposed a 10-year fishing ban to protect kelp forests which off eressential habitat for sea urchins, king crabs, and scallops.
“Our initial findings show that Patagonia’s fjords and channels remain a global climate refuge for kelp forests, which on a planetary scale have been reduced by up to 90% in some regions”
“It’s time to usher in a new era of science-based marine conservation,” says Carolina Morgado, executive director of Rewilding Chile. “These expeditions will help us better understand the Southeast Pacific Ocean by taking into account the biological wealth of Patagonia and the planet’s changing climate.”
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.
An Expedition Rooted in Scientific History
Almost 200 years after Charles Darwin made his first observations aboard the Beagle, and more than 50 years after marine ecologist Paul Dayton of the Scripps Institution of Oceanography made the first underwater observations of these forests, a new team of scientists returns to Patagonia to continue that exploratory legacy with 21st-century tools, inspired by Michael Fay’s legendary African Megatransect, which contributed to the creation of a network of national parks in Africa.
International partners supporting the initiative include the Ecological Restoration Fund and the Plum Foundation. The scientific team is led by the director of the Marine Program of the Rewilding Chile, Mathias Hüne, with colleagues Mauricio Palacios and Jonathan Poblete, and collaboration from Iván Gómez (Austral University, Chile), Alejandra Mora (University of Victoria, Canada), Julieta Kaminsky (Southern Scientific Research Center, Argentina) and Albert Pessarrodona (University of Western Australia).
The Patagonian Megatransect seeks to provide essential scientific evidence to establish a new blue geography to promote the creation of marine protected areas in southern Chile. Through each dive, data and thousands of underwater photographs are contributing to the creation of an unprecedented database and visual archive of one of the last pristine underwater forests on the planet.