Tests show red algae in NY Harbor not toxic

The red algae blooms spotted this week in a miles-long stretch of New York Harbor are not toxic, according to tests of water from Raritan Bay and near the Verrazano-Narrows Bridge by New Jersey officials.

Those results confirm what a Long Island algae expert told Newsday earlier this week: that the reddish-brown water was probably caused by a benign algae known as Mesodinium rubrum. Such blooms are not unusual and can be triggered by nutrients in sewage or urban runoff "when rainfall is low and sunshine is plentiful," according to a statement by the New Jersey state Department of Environmental Protection.

Similar patches reported off Jones Inlet were not tested and New York officials do not plan to do so, said a spokeswoman for the state Department of Environmental Conservation.

The DEC did test water from New York Harbor to determine if algae blooms there posed risks to shellfish in Raritan Bay. New York researchers were unable to locate the blooms, so they drew samples from spots where the algae was reported.

Those tests did not turn up Mesodinium rubrum, but they did show slightly elevated levels of another, potentially harmful marine organism known as Pseudo-nitzschia.

The levels were "just slightly higher than expected" but not high enough to harm anything, Wren said. In large concentrations, Pseudo-nitzschia produces a toxin that can accumulate in shellfish and sicken people who consume the tainted flesh.

A report from the Coast Guard earlier this week had labeled the blooms "red tide" - a term frequently referring to toxic algae blooms with a reddish hue - and advised swimmers and boaters to stay away.

But New Jersey and New York officials said this week that most algae blooms with a reddish hue are not toxic. They said they expected the algae to dissipate soon and that it should not impede the public's enjoyment of the water.