DEADLY ‘RUST TIDE’ SPREADING ACROSS LONG ISLAND
Southampton, NY, August 29th 2018 – A deadly ‘rust tide’ is spreading across Long Island, leaving dead marine life in its wake. Monitoring by The Gobler Laboratory of Stony Brook University’s School of Marine and Atmospheric Sciences indicates that what began as an isolated event in Eastern Shinnecock Bay earlier in the month has now spread across Great South Bay, parts of Long Island Sound, and the Peconic Estuary. Earlier this month, cell densities exceeding 30,000 cells per milliliter were detected in Old Fort Pond, Southampton, causing the deaths of tens of thousands of caged oysters and fish. Then, in mid-August, a separate rust tide emerged and spread across Great South Bay in regions between Bellport and Sayville. In the past week, bloom patches with more than 1,000 cells per milliliter have been detected across Port Jefferson Harbor, Conscience Bay, and the open waters of Long Island Sound, as well as Three Mile Harbor in East Hampton. Densities of the rust tide algae, known as Cochlodinium, above 500 cells per milliliter can be lethal to marine life. Beyond large kills in Southampton this year, prior rust tides have brought kills of both natural and aquacultured populations of fish and shellfish on eastern Long Island. Thankfully, Rust Tide is NOT harmful to humans in any way.
“We have identified climate change and specifically warm summer temperatures as a trigger for these large, widespread rust tides”, said Professor Christopher Gobler. “Compared to the twentieth century, summer water temperatures today are significantly warmer and its been a warmer than usual summer. When we have extended heat as we have seen this summer, a intense rust tides often follow.”
Beyond temperature, a 2012 paper from the Gobler laboratory identified excessive nitrogen as an equally important driving factor for rust tides. The study, published in the international peer-reviewed journal, Harmful Algae, demonstrated that high nitrogen levels make rust tides more intense and more toxic. As nitrogen loading has increased in Suffolk County waters, these events have intensified. The study also noted the flexibility of the rust tide organism with regard to nitrogen, being able to feed off of high levels in near-shore regions but also being able to persist at lower levels in more open water sites.
“The links between these toxic blooms and excessive nitrogen loading are now well-established and are playing out again this year,” said Gobler. “Near-shore, unsewered regions in Suffolk County experience intense nitrogen loading from wastewater and get these intense events first, after which they are transported to open water regions.”
And these events are geographically spreading. While they have been occurring on eastern Long Island since 2006, they were unknown to other parts of Long Island until more recently. This is the second bloom in the Port Jefferson region since 2016 and second rust tide in Great South Bay with the first being in 2011. Rust tides typically persist until water temperatures cool in September.