08/20/13 10:00am
08/20/2013 10:00 AM
Bill Portlock Courtesy Photo | Rust tide in the Peconic estuary last year.

BILL PORTLOCK COURTESY PHOTO | Rust tide in the Peconic estuary last year.

The harmful algal bloom known as rust tide has once again been detected in Peconic Bay waters — marking the 10th consecutive year the finfish and shellfish-harming algae has appeared in bay waters, according to Stony Brook University researchers.

The rust tide algae, known as Cochlodinium polykrikoides, can be lethal to marine life in levels above 500 cells per milliliter. The algae has not been found harmful to humans, however.

Densities recorded exceed 10,000 cells per milliliter in western areas of the Peconic Estuary , according to monitoring by The Gobler Laboratory at Stony Brook University’s School of Marine and Atmospheric Sciences.

Densities exceeding 1,000 cells per milliliter were also present in Flanders Bay and tributaries, including Meetinghouse Creek in Aquebogue.

“The rust tide is expected to spread in the coming days and weeks and typically extends into the fall or until water temperatures drop below 60 degrees,” said Dr. Christoper Gobler, lead researcher at the lab.

Last fall, bay scallops in the Peconic Estuary declined “tenfold” in some regions during the rust tide, causing disappointment among baymen and scallop lovers alike, according to a Stony Brook release.

The impacts of this year’s bloom will likely depend on its duration, according to research officials.

Researchers have discovered the organism waits at the bottom of the bay emerging each summer to start a new bloom. At the end of the bloom, it turns into a cyst or seed, settling back on the bay’s bottom. This allows for the blooms to return each year, researchers said.

Researchers also found “nitrogen loading makes these blooms more intense and more toxic. As nitrogen loading has increased into our bays, these events have intensified,” Mr. Gobler said.

Experiments conducted in the Gobler Lab have demonstrated that this algae can kill fish in a matter of hours and shellfish over the course of a few days, according to the release.

cmiller@timesreview.com