Researchers have just calculated the value society receives from a common but hidden underwater resource and found it to be much higher than we ever anticipated.
Kelp forests have long done so much for humanity, all the while operating invisibly beneath the waves.
They hug a third of our coastlines and provide food and home for much of our coastal seafood. In this way, these living ocean jungles supported daring human migrations such as the southern colonization of the America 20,000 years ago.
We also eat the seaweed itself, use it to fertilize plants, add it to medicines and skin care products, and breathe the oxygen it produces.
But seaweed forests are in a catastrophic declineand we don’t fully understand the extent, not to mention the value of what we lose. So a team of researchers created an estimate of the services that kelp ecosystems provide to all of us.
“For the first time, we have the numbers to demonstrate the significant commercial value of our global kelp forests,” says Marine ecologist Aaron Eger from the University of New South Wales.
“We found that 740 million people live within 50 kilometers of a kelp forest. So these systems play an important role in securing the livelihoods of these people and vice versa.”
Eger and colleagues used 1,354 surveys of fish and invertebrates in six different types of seaweed forests in eight different marine areas. They also took measures on nutrient consumption from carbon to phosphorus.
The economic value of the kelp forest’s contribution to fisheries production averages $29,851 and 904 kilograms per hectare per year, the team reports.
Surprisingly, only 50 of the 193 identified animal species contributed most of the value to the fishery, mostly invertebrates such as lobsters, sea urchins and abalone.
These ocean ‘trees’ don’t just provide Habitat for thousands of marine animals, but they also play a major role in global nutrient cycles. Kelps are a type of algae that are protistsnot plants, but just like plants, their photosynthesis brings energy to the webs of life that house them, remove carbon dioxide from their environment and produce oxygen.
removal of carbon dioxide in turn, increases the pH and oxygenation in the immediate area – helps mitigate the local effects of ocean acidification.
Kelps also absorb other nutrients such as nitrogen and phosphorus to fuel their rapid growth, with some species being able to do so add up to 50 cm height in one day. Previous research found Kelp forests are even more productive in terms of growth than intensively managed crops like rice and wheat.
“Of the three elements, nitrogen removal provided the highest economic value per hectare per year (mean = $73,831, 620 kilograms), followed by phosphorus removal (mean = $4,075, 59 kilograms) and finally carbon capture (mean = $163.00). ). 720 kilograms),” Eger and colleagues write.
While kelp’s carbon uptake may not be as impressive as its nitrogen removal, it is still on par with terrestrial forests and seagrass.
“Globally, these kelp forests are estimated to produce an average of $500 billion a year,” the team said closes. This is three times higher than previous best estimates and only a baseline measurement that has yet to take into account other significant contributions to our economy.
“There were also many other services that we didn’t evaluate, including tourism, educational and learning experiences, and seaweed as a food source, so we anticipate that the real value of the world’s seaweed forests will be higher,” Eger said qualified.
Kelp has too incredible potential as a sustainable biofuel and helps protect our coasts from erosion.
But like far too much in the world around us, kelp forests are struggling. In the last decades approx a third of all seaweed forests have suffered deep losses. A combination of heat waves and ravenous invasive sea urchins has seen one 95 percent reduction in seaweed off the California coast since 2014. Half a world away, Australia’s kelp forests were then classified as vulnerable similarly drastic declines.
They also suffer from pollution from human activities, and as these floating forests decline, so do lobsters, abalone, fish, and all the other creatures that count on their existence.
“Assigning dollar values to these systems is an exercise that helps us understand a measure of their immense value,” says Eger says. “It’s important to remember that these forests also have their own historical, cultural and social value.”
Researchers hope their findings will bring much-needed attention to this long-neglected ecosystem. They fight to restore and protect millions of acres with a global Kelp Forest Challenge.
This study was published in nature communication.
