By Rachel Bosworth
Dr. Christopher Gobler examined the decline of critical marine habitat and shellfisheries as well as inreasing nitrogen levels in groundwater in a lecture entitled “Hope at the Brink” on Friday at Stony Brook Southampton’s Chancellor’s Hall. The talk was part of Dr. Gobler’s annual State of the Bays Symposium.
With the immense concern from the public, elected officials, environmental organizations, and scientists regarding the negative impacts of excessive nitrogen loading on Long Island’s coastal marine habitats and fisheries, Dr. Gobler began with a significant explanation; “All of Long Island is a watershed. What happens on land effects what goes on in the sea,” he said.
Nitrogen levels will continue to rise unless we change course, he said. “Whether you’re on the North Shore, South Shore, or East End, we’ve got a widespread range of these different types of harmful algal blooms and low oxygen conditions, and a lot of these are driven primarily by excessive levels of nitrogen,” he explained.
Dr. Gobler and his colleagues have examined the effects of nitrogen on algal blooms, and how these blooms affect marine life and water quality. Research shows that when nitrogen levels increase, harmful algal blooms become even more toxic, threatening humans as well as marine life.
As an example of the harm such blooms can cause, he cited the death of hundreds of diamondback terrapin turtles that washed up in Flanders Bay from April to May 2015, an event linked to red tide. Scientists found that the shellfish in the tributaries along Flanders Bay reached toxicity levels that were eight times higher than the federal standard. Those shellfish make up a major portion of the turtles’ diets.
In collaboration with Cornell Cooperative Extension, Hofstra University, the state Department of Environmental Conservation, and Bigelow Labs in Maine, Dr. Gobler created a diagram showing how the turtle die-off occurred. Wastewater and fertilizer in groundwater led to increased nitrogen levels, causing a red tide and high levels of saxitoxin, a paralytic shellfish toxin, that was consumed by that bivalves. After ingesting these bivalves, the diamondback terrapins, which are endangered in some areas, died.
Blue-green algae in freshwater bodies is toxic to humans. In drinking water, it has been linked to cancer, said Dr. Gobler. The federal Centers for Disease Control reported hundreds of illnesses and deaths in dogs from drinking water with blue green algae blooms. In East Hampton, there was a reported dog death in 2012. On the East End, lakes including Lake Agawam in Southampton, Mill Pond in Water Mill, Wainscott Pond in Wainscott, Marratooka Lake in Mattituck, and Sag Harbor Cove were affected in 2015.
A bacterium called Vibrio parahaemolyticus contains toxins that can accumulate like the algae in shellfish, and only recently became a concern in New York waters. The first outbreak occurred in 2012, and another, larger outbreak occurred the following year across Cold Spring Harbor and Oyster Bay Harbor. “These outbreaks have largely been attributed to temperature, specifically the handling of shellfish on boats,” said Dr. Gobler. “When an oyster has a little bit of this bacteria in its tissue, and if it is brought up and sits on the deck of a boat for an extended period of time, the bacteria can proliferate very quickly.”
Low oxygen levels also have negative impacts on water quality. Dr. Gobler discussed the menhaden, commonly known as bunker, die-off in the Peconic Estuary that occurred in 2016. “It was a pulse of nitrogen that promoted algal blooms that led to low oxygen, essentially anoxia, and then ultimately this fish kill,” he said as a photo showed some of the reported 10 million fish that accumulated in the Shinnecock Canal.
A discussion of global warming showed the audience that though the global temperature increases by 1 degree Celsius per year on average, coastal water bodies like those around Long Island warm even more. Blue mussels that washed up on the shores of Long Island Sound in August 2016, which was earth’s warmest year on record, were reported to have experienced extreme thermal stress. As Dr. Gobler displayed a photo of Mordor, the iconic “Black Land” from “The Lord of the Rings” series, he said nutrient loading and climate change are acting together to promote both harmful algal blooms and low oxygen conditions. But the name of this lecture includes the word “hope,” and there is something to look forward to, he said.
“We’re not going to stop the global progression of temperatures, but there are things we can change and I think we now know the difference. When I think about being at the brink, I think about the hope that there are things the can be done,” he said.
Reducing nitrogen has resulted in improved water quality on Long Island, and studies show these improvements can continue to happen in the future. Dr. Gobler shared that in the last election, the Community Preservation Fund extension and expansion won by a margin of more than 70 percent, making it more popular than any politician. “It really shows that people are behind water quality because this time the CPF wasn’t just for preserving land, but 20 percent of those funds will go toward water quality improvement,” he said.
New approaches to mitigate nitrogen loading such as nitrogen-removing bio filters, wastewater treatment systems, macro algae to pull out nitrogen, and restoration programs all lend to improved water quality.
“We know excessive nitrogen loading is an ongoing threat to coastal ecosystems, and we’re now recognizing that climate change is a co-effect that is making these events more intense,” he said “Nitrogen reduction have led to improvements in water quality, and can continue to do that in the future.”