"Typically, in our Texas systems these blooms are wintertime phenomena. They last through the winter months and into the spring," Roelke said. "But the organism can be found in the water at all times of the year, and the lab work we've done shows that the conditions are optimal for growth in the summer time not winter when the blooms occur.

"This indicates that something other than the physical and chemical environment influences the timing of the blooms," Roelke added.

Already this season, several fish kills including a late August kill of perhaps "hundreds of thousands" of fish in the Brazos River near Possum Kingdom Reservoir are pointing to golden alga found in water samples, according to parks and wildlife agency logs.

A large kill of fish this early in the season is unusual but points to the difficulty of finding solutions to prevent the microscopic plant from blooming, Roelke said.

One thing seems certain: Golden alga can't take a lot of salt in the water, he said. Also, the organism grows poorly in completely freshwater systems, such as lakes in East Texas where annual rainfall rates are high.

"Our lakes located in Central and West Texas, however, tend to be salty because they receive little inflow due to rainfall," Roelke said. "The lack of rainfall is what causes these systems to become a little salty (brackish), which is optimal for growth of golden algae."

But scientists also want to examine other factors that may influence lake life in various seasons, Roelke said.

"Something must happen in the spring and in the summer that prevents it from growing," he said. "Are there some kind of grazers (micro-crustaceans) out there that are present in the spring and are able to tolerate the toxins that this golden alga produces then can consume it? Or is there perhaps some kind of a virus in the water that attacks the go
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Contact: Kathleen Phillips
ka-phillips@tamu.edu
979-845-2872
Texas A&M University - Agricultural Communications
6-Oct-2006