Microclimate all over the earth are seeing different effects from climate change, but data here shows that summers on Long Island are warming faster than the global average, said Dr. Christopher Gobler of Stony Brook’s School of Marine and Atmospheric Sciences in his annual State of the Bays address April 6.
This change continues to serve as a driving factor behind the Peconic Bay scallop die-offs of the past three seasons.
“We’re warming much faster here on Long Island, particularly during the summer, than the globe on average,” said Dr. Gobler. “The springs aren’t warmer, but the summers are. That’s problematic — already marine organisms are at their maximum temperature tolerance.”
Dr. Gobler added that warm temperatures contribute to lower dissolved oxygen levels in the water, and to the growth of the algae that causes rust tide, Cochlodinium.
The theory of the scallop die-off that has gained the most traction among scientists is that adult scallops have been under stress due to high temperatures and low dissolved oxygen levels at the time they spawn in early summer. Spawning is already a highly stressful event for the scallops. The die-off is affecting only adult scallops, while their spawn do survive only to die when they themselves spawn the following year, lending credence to this theory.
“With high temperatures, and low dissolved oxygen, bay scallops are not ok, and more rust tide is a problem for the scallop,” he said. “There are multiple stressors. We know this is happening, and this is an example of how the climate can change ecosystems and fisheries.”
Another emerging issue here is the appearance of a new, invasive red seaweed called Dasysiphonia japonica, which has been found in the Great South Bay. This seaweed, which grows faster when there is more nitrogen and carbon dioxide present in the water, causes big problems when it begins to die off and release fumes of a toxin known as caulerpin.
Craig Young, a researcher in Dr. Gobler’s lab, has been doing experiments exposing larval fish and hard clams to decayed Dasysiphonia, and Dr. Gobler said the fumes proved to be fatal to both species.
So what can be done about all of this?
This year’s address, titled “Watershed of Destiny,” focused not just on the factors that are out of our local control, but also on what is being done to combat the levels of nitrogen entering our bays, which have been proven to be driven here mostly by outdated septic systems.
Suffolk County has now mandated new, nitrogen-reducing septic systems for new construction or major renovations of houses here, and has grant funding in place to upgrade septic systems throughout the Peconics.
“Suffolk County was one of the worst counties in the country for wastewater disposal as recently as seven years ago,” said Dr. Gobler. “Right now, you could argue that there’s no county in the country with a better plan. We’re on track for upgrading 200,000 homes. We have a science-based plan and funding.”
While the costs of the new systems can easily be more than $30,000 installed, Stony Brook’s Center for Clean Water Technology has been working on solutions that they’re hoping will cost $20,000 or less.
Dr. Gobler said a Nitrogen-Reducing Biofilter (NRB) system, which consists of sand and wood chips in a box, has proved promising, and is on track for approval for general use by the county. It has also proven useful when added as a “polishing unit” attached to a Fuji Clean nitrogen-reducing septic system, one of the most frequently installed of the new septic systems.
The county’s approval last year of commercial growing of kelp on county oyster farm leases in the Peconics could also prove a boon to the nitrogen-reducing effort.
Dr. Gobler said a one-acre kelp farm could remove 100-200 pounds of nitrogen per year, the same amount of nitrogen that would be filtered by upgrading between 8 and 18 home septic systems.
Dr. Gobler’s lab is also working on a water quality app which will enable people who recreate in Long Island’s waters to learn more about the water quality at the beaches they frequent, and areas that are open for shellfishing.
“This is kind of like choose your own adventure here,” he said. “What kind of bay do you want to swim in? The choice is ours. The world’s first water quality app will help control our short-term destiny.
The app is expected to be available to the public by Memorial Day weekend.