Microscopic sea life may be threatened by underwater "smog," created when South Florida dumps treated sewage into the ocean, scientists say.
Some 300-million gallons of waste water from homes and industries spews out every day from giant outfall pipes on the ocean floor, 7,000 feet off the beach.
Scientists used to think the treated sewage dispersed rapidly, but researchers have discovered that it can get trapped in swirling underwater currents.
"What we have seen sort of resembles an underwater smog," said John Proni, the National Oceanic and Atmospheric Administration (NOAA) scientist in charge of the $1.5-million Southeast Florida Outfalls Experiment II, or SEFLOE II.
Proni said the waste could harm plankton, a microscopic animal and major link in the marine food chain.
NOAA scientists have spent the past two weeks aboard an 80-foot research ship exploring turbulent 200-foot-wide boils that form above the wastewater outfalls.
Utility officials in Broward and Dade counties who are taking part in SEFLOE II say they hope its findings will lead to a relaxation in pollution testing rules.
"It is not that we are looking for looser regulations. We are looking for scientifically founded regulations," said David Commons, an engineer at the Broward County North District Wastewater Treatment plant in Pompano Beach.
Wastewater plant operators say the tests, used to determine if creatures such as shrimp can survive in treated sewage for 96 hours, do not accurately reflect ocean conditions.
Plant operators are counting on SEFLOE II to prompt rule changes that could result in customers' savings, but NOAA scientist Jules Craynock said regulators could impose more restrictions after a final report is issued next year.