TITLE: Scientists seek answers to solve red tide puzzle

CREDIT: Associated Press

EST. PAGES: 1

DATE: 10/07/97

DOCID: FWST479611

SOURCE: The Fort Worth Star-Telegram; FWST

EDITION: NORTHEAST AM; SECTION: METRO; PAGE: 6

(Copyright 1997)

CORPUS CHRISTI - Scientists seeking to unlock the mystery of red tide now say the deadly algae may sit dormant beneath the Gulf of Mexico floor, waiting for the right conditions to reproduce.

But the greatest part of the mystery remains unsolved: What triggers the microscopic population explosion?

Thousands of manhours and millions of research dollars have been spent to answer that question and to define what constitutes the right conditions for growth.

Scientists chase the blooms, fly over the blooms, measure their concentration, but say they know little more than they knew a decade ago.

Some believe that the deadly flare-ups are the result of an ongoing arms race between ancient armies of zoo plankton, the Corpus Christi Caller-Times reported yesterday.

The enemy zooplankton flourish, red tide organisms feel threatened and fight back by releasing their powerful toxin, according to that theory.

But, experts say, the red tide algae could be protecting itself from an enemy that no longer exists.

"It could be like a defense mechanism gone haywire," said Ed Buskey, a research scientist at the University of Texas Marine Science Institute in Port Aransas.

Or the threat to algae could be real.

"Their natural predators are zooplankton," Buskey said. The red tide "keeps making more virulent toxins and the zooplankton keep adapting and becoming immune to it. We know that goes on in nature all the time, but curiously in this case the toxins aren't killing their natural enemies anymore, they're killing fish."

Another theory, Buskey said, is that red tide blooms are triggered by some unknown human-related impact. Runoff from inland livestock farms or discharge from coastal shrimp farms might contribute to the blooms.

The renewed interest in red tide began last month when Texas Parks and Wildlife Department officials sighted a dense 300-yard-wide bloom stretching for miles on the Gulf side of the southern part of Padre Island.

This weekend, dead fish were found on the Padre Island National Seashore as far north as eight miles from the seashore's north boundary. The stench could be smelled about nine miles away.

Most fish kills consist of menhaden, mullet, hardhead catfish and eel. But the toxin accumulates in oysters, mussels and clams, making them poisonous to humans.