For the most part, however, there has been little evidence of such effects, said Pierce. FMRI officials say early reports that characterized the area as a "dead zone" are not accurate because a variety of plants and animals have been found in the strange water.
Gil McRae of FMRI said the dark water is not only not a dead zone, but it teems with an "overabundance" of life. "There's a lot of productivity in a small space," he said.
That's cause for concern. While normal concentrations of phytoplankton are essential, large concentrations can mean problems for other organisms in the area. During the day, phytoplankton undergo photosynthesis and produce oxygen as well as consuming it. At night, however, the process stops and the huge masses of organisms can consume all the oxygen in an area, leading to oxygen depletion.
At the same time, the abundant "blooms" eventually die out and settle on the bottom of the sea.
Both of these processes threaten bottom-dwelling organisms such as coral, crabs, and sponges.
Although the scientists may have figured out the nature of the mysterious blob, the cause or causes remain unknown. Pierce said the scientists will "use our data to go back in time and determine what might have caused this."
One hypothesis currently under examination points to a water circulation pattern known as upwelling. The process brings nutrient-rich deep oceanic water up the continental slope and into the surface waters of coastal areas, where it fuels the growth of phytoplankton and can cause explosive growththough not usually on the scale of the Florida incident.
Runoff from rivers near the Everglades may be contributing to the problem by providing nutrients and dissolved organic matter that feed the phytoplankton explosion.
Also under consideration is a correlation with "red tide," which has been prevalent in the area since last August. Red tide is another type of algae bloom that is toxic and directly harmful to marine life.
McRae speculated that "the red tide event might have run its course, degraded, and then provided a nutrient source for the beginning of the current black-water bloom."
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