Researchers have calculated the value to society of a common but hidden underwater resource, and it is much higher than we ever expected.
The kelp forests have always done so much for humanity, working all the time out of sight under the waves.
It covers a third of our coastline, providing food and shelter for much of the coastal seafood. And in doing so, these vibrant oceanic jungles have facilitated bold human migrations, such as the southern colonization of the Americas 20,000 years ago.
We also eat algae themselves, use them to fertilize crops, add them to medicines and skin care products, and breathe the oxygen they produce.
However, the kelp forests are in catastrophic decline and we don’t fully understand how much we are losing, let alone the value of it. Therefore, a team of researchers compiled an assessment of the services provided by algae ecosystems.
Aaron Egger, a marine ecologist at the University of New South Wales, says: “For the first time, we have numbers that show the significant commercial value of our world’s kelp forests. We found that 740 million people live within 50 kilometers of kelp. So these systems play an important role in the livelihood of these people and vice versa.”
Egger and colleagues used 1,354 studies of fish and invertebrates in six different types of algae in eight different regions of the ocean. They have also taken steps to utilize nutrients ranging from carbon to phosphorus.
The average economic value of kelp’s contribution to fish production is $29,851 and 904 kilograms per hectare per year, the team says.
Surprisingly, only 50 animal species out of 193 identified have contributed the bulk of the fishery’s value, especially invertebrates such as lobsters and hedgehogs.
These ocean “trees” are not only home to thousands of marine species, but also play a huge role in global nutrient cycles. life that protect them by removing carbon dioxide from the environment and producing oxygen in the process.
The removal of carbon dioxide, in turn, raises pH levels and oxygen supply to nearby areas, helping to mitigate the local effects of ocean acidification.
The algae absorb other nutrients such as nitrogen and phosphorus to encourage their rapid growth, with some species growing up to 50 cm in height per day. Previous research has shown that kelp forests are more productive in terms of growth than more intensively grown crops such as rice and wheat.
And while carbon uptake by algae may not be as impressive as nitrogen removal, they are still equivalent to terrestrial forests and seaweeds.
The team concludes: “These kelp forests produce about US$500 billion worldwide annually.” That’s three times more than the previous best estimate, and it’s just a baseline that hasn’t yet taken into account other important contributions to the economy. There were also many other services that we did not evaluate, including tourism, educational experiments and seaweed as a food source, so we expect the real value of the world’s seaweed forests to be higher.”
Algae also have amazing potential as a sustainable biofuel and help protect our coastlines from erosion.
But, like much of the world around us, kelp forests struggle to survive. Over the past few decades, about a third of all kelp forests have suffered catastrophic losses. Since 2014, heatwaves and predatory invasive sea urchins have declined by 95% off the coast of California. Australian kelp forests have been listed as endangered following a similarly severe decline.
They also suffer from anthropogenic pollution, and as these floating forests decline, crabs, fish, and every other living thing that depends on them, are in decline.
“Pricing these systems in dollars is an exercise in helping us understand one measure of their enormous value,” says Egger. “It is important to remember that these forests also have intrinsic, historical, cultural and social value in their own right. ”
The researchers hope their findings will bring much-needed attention to this long-forgotten ecosystem.
This study was published in the journal Nature Communications.
Source: Science Alert