“Starting in 2008, after we had a very severe brown tide,” said Lobue, “we knew what the causes were, which is nitrogen pollution.”
Concrete evidence of the correlation between increased nitrogen and brown tides came in 2010 after Gobler completed his study, “Nitrogen issues and current status of Long Island’s south shore bays and the Peconic Estuary.”
“Excessive amounts of nitrogen are leading to the harmful algal tides affecting clams,” said Gobler.
According to Gobler, the initial form of nitrogen, DIN, enters the bay from the groundwater resource of Long Island. This feeds healthy and non-brown tides, but as they decay they release DON, thus fueling brown tides.
With such large amounts of nitrogen entering the bay, these tides are overpowering the clams but a manageable amount of nitrogen creates a solid base for the bay’s food web.
“Our bay’s ability to be loaded with nitrogen and not be compromised depends on the quality of the bay,” said Carl Lobue, one of the head researchers at The Nature Conservancy.