Helping the Bay Clean Itself

December 10, 1990

Finally, there is encouraging news about the health of the Chesapeake Bay.

Scientists, completing a $2.5 million research project using long-term water measurements and computer modeling, have found in preliminary studies that "nutrient loading" is dropping off. Nitrogen and phosphorus, the principal culprits causing the algae blooms that kill off valuable marine plants and animals, are being systematically reduced.

Part of that is due to the state's 1986 ban on phosphate detergents, but another major factor not to be overlooked is the continuous improvement in sewage treatment facilities along the bay's tributaries, almost $200 million worth.

Most encouraging is the discovery that the Chesapeake Bay's own pollution recyclers -- tiny bacteria, algae and plankton -- are playing a bigger role than expected in removing harmful wastes. The bacteria strip out nitrogen, converting it to a gas that escapes to the air, and the algae and plankton use up more. And the role of fish in "flushing" nitrogen by eating plants that use it and then carrying it out into the open ocean is another healthy surprise.

All this natural recycling is good for the bay, but it needs help. Studies of the Chesapeake's bottom and the bottoms of tributary rivers show that while excessive nutrients do not linger as long as once thought, important grasses and bottom-living life forms cannot easily return to bottom areas killed by too much pollution. In the Patuxent, for instance, an eight-year cleanup campaign has shown measurable progress in cutting fertilizer runoff from farms and lawns as well as phosphate pollution, but it's still not enough. Upgrading the Western Branch sewage plant will help even more, but to date the grasses which provide refuge and food for small animals and oxygen for food fish to breathe have not returned. So the emphasis must stay on helping the natural regeneration process.

The more people take that to heart, as the Chesapeake watershed population continues to increase, the better for all concerned.

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