International ecologists and economists are warning that a loss of biodiversity is profoundly reducing the ocean’s ability to produce seafood, resist diseases, filter pollutants, and rebound from stresses like overfishing and climate change. Their results are published in this week’s issue of the journal Science, and those committed to environmental awareness and organic living need to spread the word.
The study reveals that every species lost causes a faster unraveling of the overall ecosystem. Conversely, every species recovered adds significantly to the overall productivity and stability of the ecosystem, as well as its ability to withstand stresses.
“Whether we looked at tide pools or studies over the entire world’s ocean, we saw the same picture emerging,” says lead author Boris Worm, PhD, of Dalhousie University in Nova Scotia, Canada. “In losing species, we lose the productivity and stability of entire ecosystems. I was shocked and disturbed by how consistent these trends are—beyond anything we suspected.”
The four-year analysis is the first to examine all existing data on ocean species and ecosystems, synthesizing historical, experimental, fisheries’ and observational data to understand the importance of biodiversity at the global scale. The results reveal global trends that mirror what scientists have observed on smaller scales, proving that progressive biodiversity loss not only impairs the ability of oceans to feed a growing human population, but also sabotages the stability of marine environments and their ability to recover from stresses.
While the data show that ocean ecosystems still hold a great ability to rebound, the current global trend projects the collapse of all species of wild seafood that are currently fished by the year 2050. (Collapse is defined as 90% depletion.) Collapses are also hastened by the decline in overall health of the ecosystem, as fish rely on clean water, prey populations and diverse habitats.
“Unless we fundamentally change the way we manage all the oceans’ species together, as working ecosystems, then this century is the last century of wild seafood,” says coauthor Stephen Palumbi, PhD, a Pew Fellow in Marine Conservation at Stanford University in California.
The impact of species loss goes beyond declines in seafood. Human health risks emerge as depleted coastal ecosystems become vulnerable to invasive species, disease outbreaks and harmful algal blooms.
“The ocean is a great recycler,” Dr. Palumbi says. “It takes sewage and recycles it into nutrients, it scrubs toxins out of the water, and it produces food and turns carbon dioxide into food and oxygen. But in order to provide these services, the ocean needs all its working parts: the millions of plant and animal species that inhabit the sea.”
“The data show us it’s not too late,” notes Dr. Worm. “We can turn this around. But less than 1% of the global ocean is effectively protected right now. We won’t see complete recovery in one year, but in many cases species come back more quickly than people anticipated—in three to five to 10 years. And where this has been done we see immediate economic benefits.”
The authors conclude that restoring marine biodiversity through an ecosystem-based management approach—including integrated fisheries management, pollution control, maintenance of essential habitats and creation of marine reserves—is essential to avoid serious threats to global food security, coastal water quality and ecosystem stability.
“This isn’t predicted to happen; this is happening now,” says coauthor Nicola Beaumont, an ecological economist with the Plymouth Marine Laboratory in England. “If biodiversity continues to decline, the marine environment will not be able to sustain our way of life. Indeed, it may not be able to sustain our lives at all.”