By Letitia Stein
TAMPA BAY, Fla. (Reuters) - When Tampa Bay was grappling with repeated fish kills and murky waters two decades ago, the scientists who set out to restore its health by bringing back once-bountiful underwater grasses were doubtful it could be done in their lifetimes.
Yet that mission has now been accomplished. New data show Tampa Bay's seagrasses at levels not seen since the 1950s, before urban development exploded along Florida's west coast and nitrogen pollution of its waters soared.
The rejuvenation of Tampa Bay is hailed as a model for the bays and sounds in other U.S. communities seeking to restore critical coastal habitat under the Clean Water Act, from the Chesapeake Bay in the mid-Atlantic region to San Francisco Bay.
These estuaries, where freshwater from rivers mixes with the salty sea, provide a home or nursery for a wide swath of marine life, including most commercially sold fish.
Experts say the sweeping recovery in Tampa Bay is made more impressive because it appears so far unmatched.
"It shows that you can actually do it," said Rich Batiuk, associate director for science with the U.S. Environmental Protection Agency's Chesapeake Bay Program. "Kudos to them for really seeing it through and providing a great shining example."
The clean-up of Florida's largest open-water estuary has been less politically fraught than in the Chesapeake watershed, which has a dense coastal population that spans a half dozen states as well as a deep-rooted farming industry.
Tampa Bay Watch, a nonprofit focused on conservation, highlights the time and money dedicated here to returning the sparkle to the bay's 400 square miles (1,036 square kilometers).
On a recent outing in Tampa Bay, where dolphins playfully leaped, a team of the group's researchers inspected several seagrass beds that were replanted to repair damage by boats.
The water was so clear, small fish could be seen swimming through blades of seagrass.
"Pretty sweet," shouted environmental scientist Eric Plage from the water, where he was measuring the seagrasses. "There's a lot of everything."
CLEAR WATER, BETTER FISHING
A putrid dumping ground by the 1970s, conditions in Tampa Bay inspired residents to petition for a clean up. They asked for clearer water, better fishing and to swim without algae.
Seagrass was seen as the answer. It requires sunlight streaming through the water to grow and thus is an indicator of clarity. Underwater grasses provide a nursery for game fish and creates habitat that anchors their food chain.
"The seagrass has been such a primary focus because it brings in so many aspects," said Holly Greening, executive director of the Tampa Bay Estuary Program, federally created in 1990 to coordinate the restoration, then in its early phases.
The group set a goal of restoring 38,000 acres of seagrass (15,400 hectares), the quantity observed in aerial photos of Tampa Bay from the 1950s, about half of which had died. That required tackling the nitrogen pollutants chiefly responsible for clouding Tampa Bay's waters to allow the grasses to naturally rebound. Some small areas of seagrass were also replanted.
Ultimately, local governments, utility companies and other industries using the bay invested $500 million in projects that reduced nitrogen pollution, from upgrading sewage treatment plants to generating cleaner electricity.
"Until you really have everybody participating and pulling in the same direction, it's hard to achieve a lot of the accomplishments like they have in Tampa Bay," said Jeff Benoit, president and chief executive of Restore America's Estuaries, an alliance of conservation groups.
In Chesapeake Bay by contrast, pollution caps have been challenged in court by the U.S. farm lobby, and as the legal battle drags on it is not clear if the region will meet the pollution reduction targets set for a 2017 deadline, local experts said.
"If we can't restore the Chesapeake Bay, it doesn't bode well for this country's ability to achieve clean water in the Great Lakes, in the Gulf of Mexico, in San Francisco Bay," said William C. Baker, president of the nonprofit Chesapeake Bay Foundation.
"We may have to admit that Tampa Bay is the only one that did it," he added.
At the Tampa Bay Estuary Program, Greening is not yet ready to stand down. She noted the region's population has swelled by more than 1 million people during years in which the grasses were rebounding, and more development is coming.
"It will be a significant challenge moving ahead just to maintain where we are right now," she said.
(Reporting by Letitia Stein; Editing by Jill Serjeant and Richard Chang)