Scientists must acknowledge their responsibility for the effects of scientific advances by actively seeking and participating in public discussions aimed at reaching a thorough understanding of the broad consequences of seemingly simple manipulations of complex ecosystems. Ill-advised applications of science must be actively opposed by an informed public, aided by scientists with knowledge of potential harmful consequences. Nowhere is this more crucial than with potential science-based interventions in our oceans.
All life on earth ultimately depends on the oceans, which cover 71 per cent of the planet. The plants they contain provide most of the oxygen in our atmosphere, and they produce 80 million metric tons of food a year through commercial fishing. The oceans are complex systems in themselves, and they already have been affected in complex ways by human activities. We need a clearer understanding of the large-scale processes at work in the oceans, both those occurring naturally and those produced by humans, including the effects of increased fishing and of increased nitrogen (from sewage, agriculture, and industrial activity) entering the oceans through runoff and atmospheric deposition.
This was reinforced for me last year when I read newspaper stories describing the spectacular success of a group of scientists who fertilized large areas of the ocean with iron.The idea, originally proposed by John Martin, an oceanographer at the Moss Landing Marine Laboratory in California, was to increase the amount of iron in parts o the oceans that now have too little of it to support large populations of phytoplankton, single-celled ocean plants. Thee plants are of particular importance because they are the basis of food chains in the ocean and because they absorb carbon dioxide from the atmosphere. Increases in carbon dioxide in the atmosphere during the past few hundred years have been linked to global warming.
Martin speculated that about 18,000 years ago, iron from atmospheric dust fertilized the growth of phytoplankton in the oceans surrounding Antarctica and lowered atmospheric levels of carbon dioxide. He further speculated that fertilizing certain areas of the ocean with iron might have a similar effect today. To supplement findings of a small test of this hypotheses conducted several years ago, an international team of oceanographers, led by Kenneth H. Coale, and Kenneth S. Johnson of Moss Landing and the Monterey Bay Aquarium research Institute, spread 1,000 pound of iron particles across 30 square miles of the Pacific Ocean, 800 miles west of the Galapagos Islands.
This fertilization stimulated the growth of phytoplankton in the region to more than 30 times their natural level. Scientists tracked the resulting dense patch of phytoplankton by satellite as it drifted for 700 miles over the next 18 days, when observations ended. The researchers calculated that the patch absorbed 4 million pounds of carbon dioxide during that period. This dramatic verification of Martin's hypothesis has led the scientists involved to plan a third experiment, in the oceans around Antarctica.
Obviously, iron fertilization has economic implications that are attractive to entrepreneurs. For Example, the catch from commercial fishing peaked in 1989 at about 80 million metric tons. Some commercial fishers have suggested that fertilizing regions of the ocean with iron could increase the catch of fish that depend on phytoplankton for food.
Several private companies now are seeking the permission of governments, or searching for accessible international waters beyond any governmental jurisdiction, to fertilize the oceans on a grand scale for profit, in the name of feeding the world. Such large-scale manipulations should set off alarm bells. We are not ready to apply the results of iron-fertilization experiments in large-scale projects, because we have not conducted enough research to determine the long-term and possibly unintended or unforeseen effects.
This was a novel idea with potentially great benefits for research into climatic change, and a pilot experiment was successful. But other scientists and member s of the public believed that the scheme did not include adequate information about the possibility that the high-energy sound could harm animals such as whales, dolphins, and even some species of fish, which use sound to find food and mates. As a result of the public outcry which branded the scientist involved as arrogant manipulators who paid insufficient attention to possible harmful effects, the scientist have prepared an environmental-impact statement that answers most of the objections to their research. It is likely that they will conduct a larger-scale experiment in the future.
A third example dates to the 1970's but may be proposed again before long. After conducting some small pilot projects, engineers in the Department of Energy Ocean Thermal Energy Conversion Project designed plans for what were then considered colossal power plants, slightly larger than modern off-shore oil rigs, to generate power using the temperature differential between the deep and shallow waters of tropical seas.
The engineers calculated that a set of such power generators, anchored in deep water near Miami, could serve the power needs of the entire southeastern United States. They also predicted that the enormous quantities of nutrient-rich cold water drawn to the surface during power generation would slightly lower the temperature of the surface waters and change the biology of the Gulf Stream. Even this seemingly small change in temperature could push the Arctic climate farther south in Europe. The power plants were not build, because they would have been enormously expensive and not as efficient as plants using fossil fuels. But the quest for cheap electrical power has not abated, and we are likely to see similar proposals in the future.
While the results of these projects could lead to direct interventions--with potential effects of an unprecedented scale on the oceans and their species--it is clear that human population growth already is causing disturbances that demand large-scale scientific investigation. For instance, roughly 25 percent of the several hundred manatees in southwestern Florida died in early 1996 because of a red tide, the common term for a harmful bloom of algae. Red tides in this region occur when a type of phytoplankton called Gymnodinium breve blooms abundantly in the Gulf of Mexico. The plants can kill manatees when waves rupture the cells, releasing their toxin, which the manatees then inhale. While red tides can occur because of natural events - the up-welling of deep ocean water rich in nutrients for the phytoplankton, along with ocean currents that concentrate the plants - evidence suggests that human actions also can be involved.
Red tides are increasing in frequency, duration, and size all over the world, driven in many cases by pollution of shore waters by excessive chemical nutrients from sewage, agriculture, and runoff from streets, parking lots, lawns, and golf courses.
Another example of human impact on the oceans is the "cell from hell," an aggressive red-tide organism, Pfiesteria piscicida, that kills fish with its toxins and then consumes them. Its toxins are so poisonous that they are hazardous to handle even in the laboratory. The organism was implicated in the death of millions of fish in North Carolina's coastal waters in the summer of 1995. Scientists believe that the proliferation of hog farms in the state led to this red tide. When unusually heavy spring rains in 1995 produced runoff of nutrient-rich waters from those farms into the ocean, the runoff nourished heavy growth of the organism.
We may not be able to explain every occurrence of red tide or other similar events, but it is clear that the increasing concentration of people in coastal areas will inevitably increase the runoff of nutrients into the oceans. We need to learn how to prevent the damage the nutrients can cause, and find explanations for other developments, such as the higher-than-usual salinity of river mouths and inner harbors in southwest Florida in early 1996. That occurrence allowed a red tide to advance farther into manatee feeding areas last year.
We must develop comprehensive programs to study and monitor our oceans and the rivers that flow into them, rather than just react in panic when huge red tides or other unusual events occur. The oceans are too fragile to accept limitless human exploitation. They are also too important for any of us to ignore. Thus, we scientists need to concentrate our energies on maintaining the oceans and working with commercial entrepreneurs to manage, rather than exploit, them.
We now understand that human societies are changing the climate and biodiversity of the earth at a speed unprecedented in recent geological history. Understanding the impact of these changes requires scientific investigations on a scale proportionate to the scale of the problems. Proposals for large-scale scientific manipulations, along with the vastly expanded populations near our oceans, also require unprecedented public involvement and understanding if we are to sustain the health of the oceans and their resources for future generations. Scientists must reach out to the public by every means possible, including distance learning and the Internet, to develop a common knowledge of both the dangers human activities pose to the oceans and our options for protecting this essential resource.
John C. Ogden is director of the Florida Institute of Oceanography and a professor of biology at the University of South Florida
Copyright (c) 1997 by The Chronicle of Higher Education
Section: Opinion, page A48
Abstract. Large-scale technology in the oceans can lead to unanticipated negative consequences. This is demonstrated with examples of large-scaling seeding, deep ocean power plants and man-made pollution stimulated red tides. Comprehensive research is needed to provide the tools for anticipating undesirable effects of technology of biosphere.