Black "Blob" in Florida Waters Has Scientists Perplexed

Brian Handwerk
for National Geographic News
April 10, 2002

A large mass of blackish-green water floating off the Florida coast has scientists and researchers scratching their heads.

Described as "sewage-colored" and containing material that is slimy and gelatinous, the mysterious formation was first spotted in January between Naples and Key West. Research to determine its origin is underway.

Fishermen first reported the phenomenon in January, after having observed for several weeks a dark patch of water that seemed devoid of living organisms.

"We had people who spend a lot of time out on the water contacting us to say that they had never seen anything like this," said Beverly Roberts of the Florida Marine Research Institute. Satellite images confirmed the existence of the formation and showed that it was hundreds of square miles in size.

Roberts and her colleagues took the lead in coordinating a study of the problem by the state's top marine scientists. Leading experts from state and private laboratories have joined the effort to determine the origin of the unusual water-mass and determine its possible impacts on the ecology of the coast.

Roberts said the key clues will come from analyzing samples of the "dark water," which must be collected from boats.

But collecting the samples has not been easy. "Once people get us a report we try to get out there and get samples, but they can be very hard to collect," she said. Moreover, "samples only a few nautical miles apart or several hours apart can be very different," she said, and "sporadic, nonstandard sampling may result in quite varied results and interpretations."

Rich Pierce of Mote Marine Laboratory enjoys the challenge of solving the mystery. "It's exciting. We think that we understand coastal processes well, and then something like this comes along and we have only hypotheses and no clear answer about what's happening."

Not a "Dead Zone"

After their extensive preliminary research, the scientists think they have a basic understanding of the phenomenon, although they don't yet know why it formed. Pierce said the evidence so far—obtained from satellite imagery, nutrient analysis, and organic matter—suggests that the formation is a very unusual phytoplankton bloom.

Phytoplankton, consisting of tiny organisms that serve an essential purpose as the first link in the marine food chain, are common in seawater. The type of phytoplankton found in the dark Florida water "is typical of this region, so it's normally in the area and does normally bloom," said Pierce. "But what we're seeing," he added, "is a relatively normal event on a very abnormal scale."

As the scientists work to understand the causes, they are concerned about whether the phenomenon is damaging the marine ecosystem, and if so, how. Some observations have included reports of dying sponges, coral, and starfish.

Continued on Next Page >>


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