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"Black water' may be back

Scientists plan to test samples taken from a mysterious patch of discolored water off the Marquesas Keys that could be a resurgence of "black water" that affected southwest Florida into last year.

Fishermen described the patch as milky, mustard or black, in an area between the Marquesas and the Dry Tortugas. Most fish seem to avoid the area, and ones that are seen in the patch aren't biting or putting up much of a fight when hooked, fishermen said.

Researchers are monitoring the water using satellites and have ordered testing of the water, slated to begin next week. Fishermen have been given kits to gather samples and help with the study.

"Black water" first appeared in late 2001 off southwest Florida, said Chuanmin Hu, an oceanographer with the University of South Florida College of Marine Science.

When tested in 2002, it showed an abundance of nontoxic microscopic plants and was blamed on a large, nutrient-rich patch of runoff combined with a severe outbreak of Red Tide.

The new patch is "pretty much similar" though not as dark as the 2002 black water, said Hu, who has been tracking Red Tide and other algal blooms in the area.

Some sections of the mysterious water span nearly 20 miles, Hu said.

He traces it to Charlotte Harbor, 175 miles north of the Keys.

The Peace River dumps into the harbor there, after flowing through several farming communities that have nutrient-rich runoff spilling into the waterway.

Satellite images show several large algal blooms spanning from Charlotte Harbor to the Dry Tortugas, Hu said.