Coastal Runoff: Coral Reefs at Risk

Coastal Runoff: Coral Reefs at Risk

Antidepressants, fertilizers, pesticides, anti-bacterial soaps and countless other chemicals pour into the ocean off Florida's coasts each year, pumped through sewer pipes and washed off lawns, golf courses, roads and farms. Many of us in the environmental community have long suspected this chemical brew of playing a role in the decline of Florida's coral reefs. A recent study has now conclusively linked reef damage to ocean runoff.

The study was conducted by the Southeast Florida Coral Reef Initiative, an alliance of scientists, nongovernmental organizations, and government officials trying to come up with ways to protect Florida's reefs against ship groundings, coastal development and other threats to the marine environment.

The SFCRI found that corals near sewage pipes and inlets, where urban and agricultural runoff flows into the ocean, showed especially harmful changes in the ability of corals to heal wounds. When scientists cut small test holes in the corals, they found that the ones near sewage pipes and inlets took longer to heal. At samples tested near the Hollywood sewage pipe, wounds actually expanded rather than healed.

"Those are indications of environmental stress, for the most part from land-based sources," said Phillip Dustan, professor of biology at the College of Charleston, one of the authors of the study. "This is something we should have done 30 years ago, when we saw the reef was degrading. People have said you can't prove this is happening. Well, we're proving that it is."

Six sewage pipes in Broward, Miami-Dade and Palm Beach counties discharge about 300 million gallons of partially treated sewage a day into the ocean. While the sewage undergoes some treatment, it is still nowhere close to state potable (drinking) water standards.

Rich in nutrients such as nitrogen, phosphorus and ammonia, the treated sewage is fueling the growth of harmful algae blooms that smother the reefs.

Even more troubling is that reducing the pesticides, fertilizers, oils and other chemicals washing into the ocean from cities and farms may turn out to be more difficult to solve than sewage pollution. To a person spreading fertilizer on a lawn in West Boca Raton, it may not be obvious that they could be harming a coral reef 10 miles away.

In fact, most ocean pollution can be attributed to urban runoff and stormwater runoff. This type of pollution is caused by rain and river water that collects land-based contaminants and flushes them down to the beach.

In urbanized areas, runoff pollution occurs when water washes off rooftops, roads, parking lots, baseball fields, construction sites, golf courses, lawns and other surfaces. This water carries a wide variety of contaminants down to the ocean. Unlike sewage and industrial outfalls, urban runoff receives no treatment before entering the ocean.

There are Solutions.

There have been many ideas tossed around about how to correct the sewage runoff problem. The Florida Department of Environmental Protection could require additional treatment before discharge, although that would likely raise rates for homeowners. Or, plants could inject more of the sewage into deep underground disposal wells, although that practice has caused treated sewage to migrate upward into potential sources of drinking water.

Tim Powell, a DEP permitting supervisor, has a better idea: the best solution would be to recycle treated sewage to irrigate lawns, golf courses and other places that need water. In addition to reducing ocean discharges, it would ease the demand on the region's supply of fresh water.

Broward and Miami-Dade counties currently reuse only 5-to-6 percent of their sewage; the lowest percentages in the state, according to DEP figures.

There are also real solutions to urban runoff: land use planning that reduces impervious surfaces such as roads, pavement, and parking lots, will allow water to be absorbed into the ground and naturally filtered prior to running directly into the ocean. Protecting, enhancing and restoring wetlands improve nature's ability to filter polluted water.

Citizens in urban areas can also be educated to clean up after their pets, properly dispose of oil and other chemicals, and reduce the use of poisonous herbicides and pesticides. In agricultural areas, proper fencing, the use of natural buffer areas and the reduction of herbicide and pesticide use can reduce water contamination.

It really is up to us to educate the public, reduce our personal pollution, and organize direct clean-up actions to protect Florida's watersheds, coastal areas, and eventually, our reefs.