Ocean point of no return
http://www.motherjones.com/news/feature/2006/03/the_fate_of_the_ocean.html Source by Julia Whitty
Illustration: Yuko Shimizu, March/April 2006 Issue.
Bad weather at sea is exponentially worse than bad weather ashore. The liquid world reacts in a pyrotechnical way to blowing air, exploding into the marine equivalent of a firestorm at winds that onshore might only make you button your coat. We’re headed into a Force 9 (strong gale) on the 12-point Beaufort scale. Before we make landfall, one week hence, we’ll have dabbled in Force 10 (storm) and skirted Force 11 (violent storm) conditions. Force 12 is a hurricane. [...]
Concerns about weather are part of what’s sending us to sea in the first place. By studying the ocean’s chemistry, which affects currents and, in turn, weather, Curry hopes to better understand how we humans might be affecting the critical elements of our own life-support system. Data from physical oceanography, marine biology, meteorology, fisheries science, glaciology, and other disciplines reveal that the ocean, for which our planet should be named, is changing in every parameter, in all dimensions, in every way we know how to measure it. [...]
“The root cause of this crisis is a failure of both perspective and governance,” concludes the seminal Pew Oceans Commission’s 2003 report to the nation. “We have failed to conceive of the oceans as our largest public domain, to be managed holistically for the greater public good in perpetuity.” Instead, we have roiled the waters, compromising the equilibrium that allowed our species to flourish in the first place, and providing ourselves with a host of challenges that will test our clever brains and our opposable thumbs as never before. Afloat on arks of dry land, we sail toward a stormy future.[...]
Add enough warming, evaporation, and freshwater, however, and there is potential for enormous change on an accelerated schedule, including the possibility that the Atlantic MOC could shut down faster than expected, which would make Europe colder, possibly cold enough to grow new glaciers. [...]
Epidemiological studies show that mercury levels among Arctic peoples are high enough to cause neurobehavioral effects, while a Hong Kong study revealed that 10 percent of the region’s high school students suffer mercury poisoning from eating tuna and swordfish. The European Union warns pregnant women to limit their consumption of both tuna and swordfish because of brain damage to their unborn children, and the U.S. Food and Drug Administration warns pregnant women, lactating women, and young children not to eat swordfish, shark, tilefish, or king mackerel, though the powerful tuna lobby succeeded in keeping tuna off that list. [...]
Dead zones occur wherever oceanic oxygen is depleted below the level necessary to sustain marine life, a result of eutrophication, or the release of excess nutrients into the sea, usually from agricultural fertilizers. Fifty years ago no one imagined that the Green Revolution would prove so lethal to the world ocean. But now we know that chemical fertilizers cause plants to bloom in the sea as miraculously as they do on land, with deadly consequence. It’s no coincidence that almost all of the nearly 150 (and counting) dead zones on earth lie at the mouths of rivers.[...]
Among the most frightening news for coral reefs is the increasing acidity of the ocean as a result of rising levels of carbon dioxide. Scientists at the National Oceanic and Atmospheric Administration recently estimated the ocean has absorbed 118 billion metric tons of CO2 since the onset of the Industrial Revolution—about half of the total we’ve released into the atmosphere—with 20 to 25 million more tons being added daily. This mitigation of CO2 is good for our atmosphere but bad for our ocean, since it changes the pH. Studies indicate that the shells and skeletons possessed by everything from reef-building corals to mollusks to plankton begin to dissolve within 48 hours of exposure to the acidity expected in the ocean by 2050. [...]
Noise is our newest assault, including the low-frequency active (LFA) sonar used by the military to detect submarines and by the oil and gas industry to search for fossil fuels. The loudest sound ever put into the seas, LFA sonar could soon be deployed across 80 percent of the world ocean, at an amplitude of 230 decibels, strident enough to kill whales and dolphins and already causing mass strandings and deaths in areas where navies conduct exercises [see “Collateral Damage”]. A few people, misfortunate enough to be in the water near LFA sonar tests, have suffered lung vibrations, seizures, disorientation, and nausea. No one knows what effects these extreme noises have on the majority of marine life that “see” underwater with their acoustical senses.
Meanwhile, plastic pollutants masquerade as familiar marine objects. David Barnes of the British Antarctic Survey finds that invertebrates that normally hitch rides on floating wood or pumice are increasingly grabbing lifts on floating plastics; the presence of so many new “boats” has doubled the spread of exotic species in the subtropics and more than tripled it at high latitudes, threatening biodiversity worldwide. Furthermore, fish and invertebrates commonly mistake the ubiquitous pellets of partially degraded plastic, known as nurdles, for zooplankton, and ingest them, poisoning themselves and all who eat them, while sea turtles and marine mammals perish from consuming plastic bags, which resemble jellyfish.
Increasingly, persistent organic pollutants (POPs) such as DDT and PCBs are being found in such high levels in marine animals that some living creatures meet our definitions of toxic waste, including many whales, dolphins, and seals. Female mammals off-load POPs in their breast milk, lessening their own toxic load while poisoning their children. Perhaps consequently, killer whale calves from Puget Sound and the Canadian Southwest are dying in the first year; adult male orca, which have no off-loading capabilities, are also dying off. In 2005, the National Marine Fisheries Service listed this population as endangered. Currently, there is no such listing for the people who rely on marine mammal meat, even though the accumulation of POPs in the tissues of Greenland Inuits has nearly reached levels known to suppress the immune system.
The problems facing the world ocean are virtually all human-induced, and many are beginning to cross-pollinate. Jellyfish populations expand in response to red tides and hypoxia, as well as to the depletion of their competitors, such as menhaden [see “Net Losses,”]. This, combined with the virtual extinction of jellyfish-eating sea turtles (leatherbacks have declined 97 percent in 22 years), leaves more food for those jellies that prey mostly upon other jellyfish. Thus the nearly independent jelly web is expanding—and increasing its impact on human fishers, including forcing the closure of the Gulf of Mexico shrimp fishery in 2000, when 25-pound jellyfish native to Australia swarmed so heavily that shrimpers were unable to retrieve their nets.
In a similar vortex of cause and effect, researchers from NASA and the U.S. Geological Survey forecast that Alaskan earthquakes will increase in the wake of retreating glaciers, triggering more tsunamis, as happened dramatically in similar warmer epochs of the past. Freed of the immense weight of these rivers of ice, tectonic stresses are released, sometimes for the first time in millennia. Many scientists also believe that a warmer ocean is making hurricanes bigger, faster growing, and stronger, with 2005’s Hurricane Wilma prompting a call for a new Category 6 on the Saffir-Simpson scale, or a new scale altogether. And because bigger storms destroy more coastal wetlands and mangrove forests, they also incidentally reduce the land’s natural buffering against storms and earthquake-generated tsunamis.
Even as we spend millions looking to space for dangerous asteroids that might threaten all life on earth, we are the asteroid that has already landed. A modeling study from the National Center for Atmospheric Research in Colorado suggests that global warming, not an asteroid strike, triggered the earth’s most severe extinction event 251 million years ago during the Permian-Triassic era, long before the dinosaur die-off. Atmospheric CO2, fueled by massive earth-building volcanic eruptions in Siberia, warmed the ocean to depths of 10,000 feet, increasing salinity, shutting down the ocean conveyor belt, and trapping oxygen and nutrients so deep that most of the world ocean became a hypoxic dead zone. With hardly any sea life left to scrub the atmosphere of carbon dioxide, global warming accelerated. In the end, the Great Dying came close to destroying all life on earth, precipitating the demise of 95 percent of all marine species and 70 percent of all terrestrial vertebrates, leaving fungi to rule the world for many an eon.
AT NO TIME IN HUMAN HISTORY has so much scientific inquiry been focused so intensively in one direction: on the anthropogenic changes in our world. As a result, we are learning more, and more quickly than ever before, about how the life-support systems of earth work. Science now recognizes that the ocean is not just a pretty vista or a distant horizon but the vital circulatory, respiratory, and reproductive organs of our planet, and that these biological systems are suffering. Much effective treatment is suggested by computer-modeling studies, which the Bush administration, with its fear of science, negates—even though computer models are the same powerful tools that enable us to put men into space, to run wars, and to forecast financial trends.
Back aboard Oceanus in the stormy North Atlantic, we’ve reached the Gulf Stream at last, where the seas have stretched out with the increased depth, easing our ride a little. Surrounded on every horizon by menacing black skies, complete with downpours and bolts of lightning, we bask for an hour or two in a spotlight of sunshine that illuminates the endless cobalt of the deep, the platinum spray of the surface. Three of us—Ruth Curry, Guy Mathieu, and I—are out on deck tending the CTD, which has just returned from its four-hour journey to the bottom of the ocean. Mathieu, a retired scientist with the Lamont-Doherty Earth Observatory, is collecting samples from the Niskin bottles for analysis of their chlorofluorocarbons—those synthetic chemicals in refrigerants and aerosols so damaging to the Earth’s ozone layer, yet so useful as tracers for measuring the timescale of movements within the ocean conveyor belt.
Curry taps the bottles for oxygen analysis, and I follow up collecting salinity samples. Although conditions are wet, rough, and slippery, we smile, enjoying our time on deck. Five hundred miles from land, we are deep inside the embrace of the ocean, and as we work, we are touching water that an hour or two ago rode the Deep Western Boundary Current 17,000 feet deep, headed for Antarctica. The sea, always a place of awe, is made even more awe inspiring by the feel of its cold, buried tides.
In late 2005 a British oceanographic team, conducting research similar to Curry’s, announced findings that the Atlantic MOC—the critical factor keeping the North Atlantic warm—has slowed by 30 percent. Although the surface Gulf Stream apparently still flows as usual, the deeper waters are undergoing massive, silent changes, with virtually all of these shifts rapidly taking place since 1998.
But aboard Oceanus, this news is still six weeks in the future, and we are happy, at least in this moment, to be at sea in bad conditions collecting good data that may well lead to bad news. The tempest around us is beautiful yet seemingly manageable—that is, until the winds, whistling steadily at 40 knots, increase sharply, ripping off the whole surface of the sea, not just the tops of the swells. The whistling grows ominously louder and splits into harmonics of deeper- and higher-pitched voices. Literally over our heads, the low-pressure storm systems have merged, and within the hour we’re running south as fast as Oceanus will go.
No one who survives time at sea is ever less than humbled by its powers over life.
Link to Oceanus magazine
Sea pollution google map.
A voronoi diagram is a way of decomposition or subdivision of space based on an initial set of objects or points (for more information 