. Coast watch. Marine resources; Oceanography; Coastal zone management; Coastal ecology. pollution from contaminated runoff, Rader says. Wetlands near the headwaters of streams are the most important in removing pollutants such as sediment and nitrates, according to some research- ers. These areas are less likely to be inundated for extensive periods. "When water flows over the land, it carries with it sediments, nutrients from fertilizer and toxic metals that pose a real threat to surface waters," says Rader. He estimates that more than 60 percent of the state's surface water degrad
. Coast watch. Marine resources; Oceanography; Coastal zone management; Coastal ecology. pollution from contaminated runoff, Rader says. Wetlands near the headwaters of streams are the most important in removing pollutants such as sediment and nitrates, according to some research- ers. These areas are less likely to be inundated for extensive periods. "When water flows over the land, it carries with it sediments, nutrients from fertilizer and toxic metals that pose a real threat to surface waters," says Rader. He estimates that more than 60 percent of the state's surface water degradation is caused by non-point source pollution, primarily agricul- tural in origin. Turbid waters can create real problems in the aquatic community. Excess sedi- ment buries the eggs and larvae of fish and other aquatic organisms on river bottoms. It also interferes with the respiration and filter feeding of aquatic organisms and prevents light from reaching bottom-dwelling plants. "In landscapes where wetlands are still intact, the vast preponderance of sediment is trapped by wetlands," says Rader. Wetlands also convert potentially harmful nutrients such as nitrates and phosphates — which can cause algal blooms and fish kills in coastal basins — into nourishment for microorgan- isms adapted to the anaerobic condi- tion of wetland soils. If these wetlands are lost, the additional nitrogen pollution could require billions of dollars in improvements to sewage treatment plants alone, some scientists say. Because of their ability to remove nutrients and minerals, some wetlands — such as cypress swamps — have. Doug Rader, Environmental Defense Fund Regulations should be made according to id values. not more or less protected. but differently,1 Rader says. actually been used as a natural method of sewage treatment. In other areas, people have constructed artificial wetlands to cleanse polluted water. Because they absorb sediment and nutrients, wetlands can
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