Don't Surf NY's Channels Today: Algae Bloom in the Big Apple

In case you’re missing the long hot days of summer 2010, and thinking about a little ocean dip to refresh yourself, you might want to wait a week if you’re in New York. The Big Apple is being visited by a 10-mile long reddish ribbon of an algal bloom, which could produce health-harming toxins. An algal bloom is a proliferation of tiny microalgae; some of these produce potent toxins that can harm people, pets, and marine life, and contaminate aquatic food chains.

The early-September bloom stretches from the site of the Intrepid Sea Air & Space Museum in Manhattan down to Staten Island, with another patch in Long Island Sound.  People are already calling this a “red tide” – but we don’t really know yet if it’s a Harmful Algal Bloom (HAB), whose species produce the toxins that can kill fish, contaminate seafood, and harm human health. The NJ Department of Environmental Protection is testing water samples to find what algal species are in the bloom.

Just to be safe, the Coast Guard is warming swimmers and boaters not to touch the reddish-brown floating stuff.

Other “red tides” appeared in the waters off Sag Harbor, Long Island back in late July, about a month ahead of schedule according to some experts. This was around the same time that an enormous algal bloom in the Baltic Sea covering 145,000 square miles—an area larger than Germany—also appeared.

Record-breaking 2010 summer heat may well have contributed to those blooms, along with high nutrient levels from fertilizers or wastewaters, or lack of winds.

Studies suggest that climate change can also increase risks of HABs in marine or freshwater bodies, as it heats up the air and water, or changes rainfall and wind patterns, often creating conditions favorable for their growth.

For people with asthma, spending even one hour at a HAB-affected beach can hamper breathing up to 5 days later – and aerosolized toxins can travel up to a mile inland. Emergency department visits associated with the 2005 red tide blooms in Sarasota County cost an estimated $4 million.

In 2005, an unusually large and long-lasting bloom of the red tide species Karenia brevis occurred off the coast of West Florida. The bloom caused massive fish kills and reports of respiratory irritation in beach-going tourists and people living near the shore. It was estimated that 2,000 square miles of the Gulf Coast sea bottom west of central Florida was severely oxygen-depleted. A similar 1971 event cost $20 million in tourism-related losses; or in 2005 dollars, an estimated $96 million.

For more information on HABs, take a look at NRDC’s newly-released factsheet, Tides of Trouble: Increased Threats to Human Health and Ecosystems on our website.

And stay tuned for what the tests show about what’s living in the waters of the Big Apple.

About the Authors

Kim Knowlton

Senior Scientist and Deputy Director, Science Center

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