kelp forest


A new study highlights the crucial role of kelp forests in sustaining coastal environments and supporting fisheries that contribute billions of dollars in economic benefits.

However, the world’s kelp forests are facing multiple threats, including the climate crisis, overfishing, invasive sea urchins, and pollution. The study, led by marine ecologist Eger and a team of researchers from 10 countries, sheds light on the under-appreciated and understudied importance of kelp in absorbing nitrogen, phosphorus, and carbon, thus maintaining the health of coastal ecosystems.

“They are the forests of the sea,” said Dr Aaron Eger, the study’s lead author. “If we lose these kelp forests, then we lose the oceans as we know it across massive regions all over the globe.”

According to the study published in Nature Communications, approximately 740 million people worldwide live within 50km of marine environments dominated by kelp. The researchers assessed six common types of kelp and quantified the amount of nitrogen, phosphorus, and carbon dioxide absorbed by kelp forests globally. For the first time, they also assigned monetary values to these ecosystem services provided by kelp forests.

Kelp forests play a vital role in absorbing excess nitrogen and phosphorus from land runoff, effectively reducing pollution in coastal waters. Additionally, it is estimated that kelp forests worldwide absorb around 18 million tonnes of CO2 annually. These ecosystems also serve as crucial habitats for a wide array of species and provide the foundation for lucrative fisheries, supporting the harvest of abalone, lobsters, and reef fish. On average, each hectare of kelp forest annually supports approximately 900kg of harvested fish and seafood.

Eger explained that when nitrogen from land-based activities like farming and industry enters the oceans, it can trigger the rapid growth of microscopic algae. As this algae dies off, it depletes oxygen levels in the water. However, kelp forests absorb significant amounts of nitrogen, improving water quality and creating habitats for marine life.

“This is just a baseline study, so we expect the approximations will get more accurate as the field advances,” Eger said.

“There were also many other services we didn’t assess, including tourism, educational and learning experiences, and kelp as a source of food, so we anticipate the actual value of kelp forests in the world to be higher.”

Unfortunately, many regions have experienced substantial losses of kelp, with some areas, such as northern Tasmania, Western Australia, and northern California, recording declines of up to 95%. Factors contributing to these losses include marine heatwaves that kill off the kelp and overfishing, which disrupts the natural balance by removing the predators of sea urchins that graze on kelp.

“They are taking it from all fronts, but leading those is temperature,” Eger said. “In most places, we’re looking at slow or precipitous declines of kelp forests.

“The kelp is what’s holding everything together and, if you pull at it like a thread, then you unweave the whole tapestry.”

To address these challenges, Eger’s not-for-profit organisation, the Kelp Forest Alliance, is working to raise awareness about the importance of kelp and promote conservation efforts worldwide. Some measures being implemented include the physical removal of sea urchins, improved pollution control, and kelp replantation, which can experience rapid growth under favourable conditions.

The study underscores the need for urgent action to protect and restore kelp forests, which are vital for maintaining the health of coastal ecosystems, supporting fisheries, and mitigating climate change. By recognising and addressing the threats facing kelp forests, we can preserve these valuable ecosystems and the benefits they provide to both nature and human societies.



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The declines in our wildlife is shocking and frightening. Without much more support, many of the animals we know and love will continue in their declines towards extinction.

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We are convinced that this is much better for the UK than growing lots of fast-growing coniferous trees, solely to remove carbon, that don’t actually help our animals to thrive.

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