Windswept_ The Story of Wind and Weather - Marq de Villiers [98]
At Tagish in the Canadian Rockies a monitoring station has found elevated levels of pesticides in the winter and spring, attributed to pollution from continental Asia. Similarly deleterious effects have been noticed in focused studies of snow cover in Alaska and British Columbia and on the fecundity of Pacific eagles. A study on the Fraser River watershed in British Columbia concluded that toxic airborne pollutants from Asia have been contaminating lake fish and sediments; high POP concentrations have been found in the snowpack. Farther south, increased nitrates and sulfates have been detected in pristine streams in the Olympic National Forest on the coast of Washington State. Other studies document POPs and mercury in wildlife and human populations in the Arctic, pesticides in bald eagles of the Aleutian Archipelago, and very high polychlorinated biphenyl (PCB) concentrations in some Pacific Northwest orca populations.6
Asia is hardly the only villain—villains are to be found wherever winds blow. In late 2004, for example, Arkansas soybean farmers were lamenting the ravages of soybean rust, a fungus that had landed in the United States, blown from South America and carried ashore over the Gulf of Mexico by one or another of the season's hurricanes. The fungus was also attacking another alien import, kudzu, which state governments had been vainly fighting for decades, so many people who were not growing soy could see the bright side.7
And I had seen for myself how strong winds picked up massive clouds of African dust, and carried them out over the Atlantic. This, too, was hardly new: For decades it has been known that pre-Columbian pottery in the Bahamas was made from wind-borne deposits of African clay; orchids and other epiphytes growing in the rain forest canopy of the Amazon depend on African dust for a large share of their nutrients. Charles Darwin's Beagle journals contain an observation he made as he was crossing the Atlantic about the falling of "impalpably fine dust" on the ship at sea.
In the last year of the millennium a reddish brown river of dust, picked up from the deserts and the eroding grazing lands of the Sa-hel, a plume hundreds of miles wide and thousands long, was whipped across the Atlantic by the trade winds. The amount of transported dust has been going up steadily over the past twenty-five years, and at the same time, the mortality rate of creatures like Caribbean coral has risen sharply. Eugene Shinn, a researcher with the U.S. Geological Survey in St. Petersburg, Florida, has tracked the coral's declining health to fungal spores and bacterial cysts hitching a ride on African sand; in 1998, scientists identified an African soil fungus as the cause of the decimation of sea fans across the entire Caribbean, an object lesson in the interconnectedness of life. The red sunrises in Miami are Saharan-caused; half the particulates landing on Florida are from the Sahara. Dust clouds increase in Caracas when drought in the Sahel occurs—another example of the intimate links that winds make.
The same thing has been happening in the U.S. Virgin Islands, where the coral reefs have been dying for years. Most of the blame had been attributed to overfishing and to direct damage by boats and divers; but in 2000 several studies found that hurricane-carried pathogens from Africa had severely degraded vegetation and had critically damaged once-dominant corals like staghorn and elkhorn, long-spine sea urchins, and sea fans. Carpets of algae now dominate many reefs. The Virgin Islands National Park even paid for a marine