Along thousands of kilometers of coastline, the sea hides a valuable natural treasure: the forests of **giant algae**.
“These are very relevant ecosystems. They are linked to temperate to cold coasts and are as important as corals in **equatorial latitudes**,” says Chilean geographer Alejandra Mora to DW portal.
Using satellite images and drones, the postdoctoral researcher from the Department of Geography at the University of Victoria, Canada, has created the first **world map of macroalgae**.
This map shows the prevalence of these giant algae in coastal areas of **temperate to cold waters** and around rocky coasts. “They are three-dimensional structures that provide shelter for many species that manage to live there all or part of their lives,” highlights Mora.
The **giant kelp** (Macrocystis pyrifera), a brown algae, is found in southern Australia, parts of Tasmania, Baja California, Mexico, up to Alaska, in South America, as well as in South Africa and the subantarctic islands. “Only in Chilean Patagonia, there are 5,600 square kilometers of giant kelp forests,” points out Mauricio Palacios, associate researcher at Rewilding Chile Foundation.
Ecological importance of macroalgae
“Macroalgae are probably the **largest marine organisms**. Kelp can reach up to 70 meters. In most coastal systems, they are the basis of productivity, providing habitat, food, and supporting chemical processes,” explains Iván Gómez, director of the Center for Research in Dynamics of High Latitude Marine Ecosystems (IDEAL) at the Austral University of Chile (UACh).
These ecosystems are very productive and **absorb large amounts of atmospheric carbon**, converting it into tissue. “They create productive habitats that host a wide diversity of mollusks, fish, dolphins, otters, sea lions, and birds, which also contribute nutrients to the algae,” adds Mora.
Distribution and conservation
40% of the world’s giant kelp forests are in the southern hemisphere, especially in **Chilean and Argentinean Patagonia**. 33% are concentrated in the Chilean part. “Over 70% of global fisheries depend on the well-being of these algae ecosystems,” emphasizes Palacios.
Giant algae are **harvested for consumption** and are sources of chemicals, antioxidants, vitamins, and gelling agents for the food and pharmaceutical industries. They also serve to manufacture synthetic leather and as an alternative to animal-derived gels. However, in Chile, intensive exploitation has led to a **conservation crisis**.
Disappearance and protection
The global loss rate of these forests is between 1.8% and 2% annually, with the highest temperature zones being the most affected. In Mexico, more than 50% of these forests have been lost. The main threats include illegal harvesting, global warming, and inadequate **supervision in protected areas**.
In a letter published in the journal Science, over 230 scientists from 18 countries warn about the need to increase effective protection of these forests in Latin America’s environmental policies. This letter, co-authored by Palacios, emphasizes the importance of conserving biodiversity and **climate resilience** through protected areas.
Conservation and the fight against climate change
Macroalgae have emerged as organisms that can help **mitigate the effects of climate change** by absorbing CO2 from the environment.
Research and conservation efforts are advancing in the protection of these vital marine ecosystems.
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