Microbe's toxic hunting habits could help curb massive fish kills

Washington, January 22 (ANI): A team of researchers from four universities has discovered that a microbe commonly found in waterways emits a poison not just to protect itself, but to stun and immobilize the prey it plans to eat, which could help curb massive fish kills.

The researchers studied the behavior of the algal cell Karlodinium veneficum, known as a dinoflagellate and found in estuaries worldwide.

Each year, millions of dollars are spent on measures to control dinoflagellates around the globe.

This particular species is known to release a substance called karlotoxin, which is extremely damaging to the gills of fish.

Karlodinium veneficum has been known to form large algal blooms in the Chesapeake and elsewhere, triggering an immediate harmful impact on aquatic life, including fish kills.

The researchers found that K. veneficum microbes release toxins to stun and immobilize their prey prior to ingestion, probably to increase the success rate of their hunt and to promote their growth.

This significantly shifts the understanding about what permits harmful algal blooms to form and grow, the researchers said.

Instead of being a self-defense mechanism, the microbes' production of poison appears to be more closely related to growth through the ingestion of a "pre-packaged" food source, the cryptophyte cell.

"This new research opens the door to reducing bloom frequency and intensity by reducing the availability of its prey," said Allen Place of the Institute of Marine and Environmental Technology at the University of Maryland Center for Environmental Science.

"As we reduce the nutrient load feeding Karlodinium's prey and bring back the bay's most prolific filter feeder, the Eastern oyster, we could essentially limit Karlodinium's ability to bloom," he added.

"This is a major environmental problem, but we didn't know why these microbes were producing the toxins in the first place," said Joseph Katz, the William F. Ward Sr. Professor in the Department of Mechanical Engineering at Johns Hopkins and a co-author of the research.

"Some people thought they were just using the toxins to scare away other predators and protect themselves. But with this new research, we've provided clear evidence that this species of K. veneficum is using the toxin to stun and capture its prey," he added. (ANI)