The text on this site is presented as an archival version of the script of "Ocean Planet," a 1995 Smithsonian Institution traveling exhibition. The content reflects the state of knowledge at the time of the exhibition, and has not been updated.

Side effects spread from land to sea

Identifying a water polluter is a snap when you spot a single pipeline spewing wastes. It's not so simple when you consider that the line-up includes nearly everything we do on land. It all contributes to nonpoint-source pollution--polluted runoff that enters surface, ground water, and the oceans from widespread and distant activities. It can lead to beach and shellfish-bed closings, and spoiled habitats for fish and other aquatic life.
Chesapeake Bay watershed, Maryland
photo © David H. Harvey/Woodfin Camp & Associates

Warning Signs

Too many nutrients lead to too little oxygen

Too much nitrogen (from fertilizers, sewage, feedlot runoff, or air pollution), or too much phosphorus (from the same sources, as well as detergents or water-treatment chemicals), can set off explosive growth of algae and aquatic plants. As the overpopulated plants and algae die off, bacteria can deplete oxygen from the water as they decompose the dead plants. Lack of oxygen kills fish and other animals §.

Pond after nutrient build-up
Chesapeake Bay Watershed, 1994
photo © David W. Harp

Gulf bottom-dwellers die in the "dead zone" The Mississippi River drains nearly half of the continental U.S., carrying excess nutrients into the Gulf of Mexico §. During the summer, decay of the resulting algal blooms consumes oxygen and kills some animals and drives away others in a 4000-square- mile bottom area (10,360 sq km) off the coast of Louisiana and Texas §.

A "dead zone" occurs in the Gulf of Mexico each summer as nutrient build-up leads to drastic reductions in oxygen in bottom waters. Fish and shrimp catches virtually disappear § §.

First Aid

Iowa farmers reduce runoff pollution

In 1981 government agencies began farm-management and water- quality monitoring programs in northeastern Iowa's Big Spring Basin. Using fewer pesticides and fertilizers, and other good farming practices such as crop rotation and contour planting, has lowered nitrate levels in Big Spring Basin ground water. § §

Analyzing barnyard manure for nutrient content allows farmers to use manure as an alternative to commercial fertilizers for corn, and to control nutrient-laden runoff from livestock operations.
photo © Kathie Bentley, Northeast Iowa Demonstration Project

Managing hazardous waste hits home

Many products for home and garden can burn, explode, corrode, or poison. Dumped down the drain, onto the ground, or into the trash, they can pollute water, pose health risks, and damage water-treatment systems. Since 1980, thousands of community programs have begun to collect household hazardous waste. § §

Get a handle on household hazards

To cut your "pollution contribution," use less hazardous or safe products if you can. If you can't, use only as much as you need; share leftovers with neighbors, businesses, or charities; and dispose of leftovers safely.

The Chesapeake Bay depends on the kindness of many strangers

The Chesapeake Bay's watershed covers six states and the District of Columbia, and drains 150 rivers and streams--an enormous catch-all for urban, suburban, and agricultural pollution. A landmark 1983 government agreement launched efforts to clean up the bay § §. Successes include reducing nutrient pollution from farming and livestock, bans on phosphate detergents and tributyl-tin boat paints, and legal protection for environmentally sensitive shorelines §.

Storm-drain signs remind Baltimore neighbors that discards can harm the Chesapeake Bay.
photo © David W. Harp, Chesapeake Bay Foundation

Other Resources:

Ocean Planet Exhibition Floorplan

gene carl feldman ( (301) 286-9428
Judith Gradwohl, Smithsonian Institution (Curator/Ocean Planet)