Losing Nemo: Is There Time to Save the Seas?
Filed under: Discovery,News & Resources
(Click to enlarge image) Orca (Orcinus orca), Antarctica (Credit: Art Wolfe)
The ocean is acidifying and coral reefs are dying. And it will only get worse until we rein in our emission
(From TimesOnline) — The glistening back of a whale sends ripples across the surface of the Arctic Ocean. Terns wheel overhead, while in the crisp, clear water beneath, tiny translucent sea snails flap their feet like butterfly wings against a shimmering backdrop of fish. The ocean is boundless, timeless and about as far away from Man as it’s possible to get. But not far enough.
The waters of the Arctic are changing faster than anywhere else on the planet. Glaciers are melting ever quicker and the sea ice is retreating, but these are only the physical effects of the fumes pouring from humanity’s smokestack. Our emissions are shifting the ocean’s chemistry too, and the combination is shaking the very foundations of its biology.
Just as ocean currents encircle the world, so too will these transformations. By mid-century the reefs shielding the Maldives will be eroding faster than they can grow. And out beyond the reefs’ ash-grey remains, a still more sinister threat will be reaching up from the depths.
Standing on a clifftop gazing out at the wild sea, it’s easy to feel the ocean’s power to recharge. Marine life is at once the lungs and the kidneys of the planet, providing half its oxygen, recycling its nutrients and absorbing its waste. Take a deep breath of that fresh sea air, and your chest swells with the scent of ocean life.
If the UN summit in Copenhagen ends with more half-hearted commitments, come the middle of the century you — and the other 80 per cent of the world’s population who live within 100km of the coast — had better think twice before drinking in that sea breeze. The characteristic scent is the product of microscopic, surface-dwelling plankton, but rival species are on the rise. A lungful of their fragrance leaves not the feeling of freedom but toxic irritation.
The ocean’s valiant efforts to keep absorbing human waste are jeopardising its future. Beyond the PCBs, the DDT, the mercury and the plastic, the ocean has also absorbed 550 billion tonnes of carbon dioxide in the past two centuries. It is the pace as much as the scale of this that is the problem.
Scientists are struggling to keep up. The oceans make up 93 per cent of the world’s living space, and in none of it does useful light penetrate more than a hundred metres. It takes a fearless mind to study such a huge, alien world, yet those who have been grappling with it longest are the most fearful for its future.
Finning through an ornate coral jungle surrounded by rainbow-coloured clouds of fish is wonder enough. But stop and look closer at a head of coral, and your mask fills with a heart-stopping, fractal complexity. Every nook and cranny teems with waving polyp tentacles, intricate invertebrates or sheltering baby fish. It’s hard to believe that when I am as old as my father is now, it is likely they will all be gone.
Coral reefs are the canaries in the coalmine of our planetary crisis. Just as the bright yellow birds keeled over when the air in a mine had turned foul, so coral reefs can die from bad air. The shock of warming waters has already turned a fifth of the planet’s most spectacular and colourful ecosystem the sullen grey of death. A further 35 per cent of corals are threatened, and most marine scientists believe that by 2050 warming waters will be bleaching the corals every year, giving them no chance to recover.
Dr John “Charlie” Veron lives by the Great Barrier Reef, and has spent his life studying it and other reefs around the world. His early statements of concern, along with those of every other coral researcher, have become shouts of alarm.
“Unless there’s a very major turnaround, carbon dioxide emissions will lead to utter destruction of reefs by mid-century at least,” he says. “I’m no Ancient Mariner. I’m just putting forward an amalgamation of all the best science on the planet. Coral reefs will be the first planetary ecosystem to go. There’s no doubt about this. Nothing is going to protect the Great Barrier Reef and others against the levels of CO2 being discussed.”
Of course this is no symbolic loss of a sacrificial canary. Although reefs occupy only 0.2 per cent of the ocean’s area, they harbour a third of all marine life, most of which is found nowhere else on the planet. They also shield thousands of kilometres of coastline, defending lagoons and mangrove forests that nurture the young of yet more marine species and act as potent carbon sinks. In the language of raw economic value, they’re worth more than £200 billion a year.
Anywhere in the ocean’s uppermost waters there are specks of life. Squint and you can see the pulsing, otherworldly shapes of plankton. Tiny they may be — most are invisible without a lens — but they are the most spectacularly abundant organisms on the planet. Enormous blooms of light-fuelled phytoplankton are, along with coral reefs, the only biological phenomena that can be seen from space with the naked eye.
Although they are the primary engine of the planet’s productivity, plankton remain little understood. Scientists in Plymouth are among the few to have been studying them for long enough to be able to gauge what is happening to them.
One of these is Professor Chris Reid, the former director of the Sir Alister Hardy Foundation for Ocean Science. He has been studying the fly-like Calanus finmarchicus, a plankton species that forms a crucial part of the diet of fish across the North Atlantic, including cod. Having analysed data from more than 5 million miles of survey trawls made since the 1930s, Reid has made an alarming discovery.
“Warm-water plankton are moving north very rapidly, and the cold-water species are retreating,” he says. In just 40 to 50 years, their ranges in the northern hemisphere have shifted northward by more than 1000km. The adaptability of microscopic marine life is no comfort. Marine food webs are highly complex, having evolved over millions of years. Force change on an ecosystem and those webs will tend to shrink, at the expense of magnificent whales or the fish we consume.
Reid is trying to monitor the changes, but even with the help of a global network of scientists, their speed and scale are hard to grasp. In each ocean, warming surface waters are causing subtropical gyres — currents encircling limpid, desertified waters such as the Sargasso Sea — to expand. The currents are wavering and shifting, altering age-old synchronicities such as the hatching of fish larvae just as the plankton bloom. “The seasonal timing of larval forms is changing dramatically,” says Reid. “In the North Sea we’re now seeing a mismatch. The larvae of fish are hatching when plankton is not there for them to eat.”
