Water quality improving in Long Island Sound, report says
NEW HAVEN — Newly released information shows Long Island Sound’s water quality is getting better.
Environmentalists announced Monday the results of the “Long Island Sound Report Card 2018,” which tracks the conditions of the Sound’s ecosystem. The report includes 10 years of data and an assessment of how water quality is trending in each region of the Sound. In most regions, the water quality improved.
The report grades the water areas based on oxygen levels, water clarity, the amount of phytoplankton in the water and levels of dissolved organic carbon. These water quality indicators were compared to scientific standards for marine health and the five geographic regions of the Sound were graded based on the scores in each category.
Two crucial measures of the Sound’s health are nitrogen levels and dissolved oxygen. Excess nitrogen in the Sound causes hypoxia, the biological process of nitrogen stimulating excessive growth of aquatic plants, which die and get consumed by oxygen-using bacteria. In turn, the low levels of dissolved oxygen reduce growth and reproduction in marine life and at low enough levels cause death. The phytoplankton, which are micro-algae, use the nitrogen entering the Sound to grow, also affecting water clarity, a measure of how far light penetrates through water. In clear waters, fish easily find prey and underwater plants thrive.
“Excess nitrogen is viewed by scientists all around the globe as being one of the seven deadly sins that humans create to the ecosystem,” said Curt Johnson, president of Connecticut Fund for the Environment - Save the Sound. “It’s right behind global warming, air pollution, right there with many of the catastrophes that are facing us.”
The excess nitrogen effectively sucks oxygen out of the water, harming marshes and turning the water green. Nitrogen carried through fertilizers and sewage pollutes aquatic ecosystems through storm water runoff. Phytoplankton thrive on that sewage but in turn consume too much oxygen for fish to survive. Efforts to reduce nitrogen producing materials have improved the overall health of the Sound.
“Many of the urban estuaries around the Sound are crashing so today’s reports is all about ecological health of Long Island Sound,” Johnson said. “It’s not about bacteria and human health. It’s about the health of the Sound. This is one of the very few estuaries in the country and perhaps the world that’s making real progress.”
The results speak to open water conditions only, not bays, harbors and watershed areas that flow into the Sound and behave differently by carrying other types of pollution from homes and developments along various watershed areas. A report on these waters will be release in 2022.
The Sound’s overall condition improved dramatically since the late 1980s when a steady increase in population and poorly treated sewage led to harbors full of dying fish and shellfish, dirty beaches and waters almost devoid of oxygen. Johnson said In 1989, the water quality in the Sound from Bridgeport and westward was nearly catastrophic — belly up fish, garbage and wiped out shellfish beds.
“I grew up in Connecticut and remember all the times the beaches were shut down because it was unsafe to swim,” said Justin Elicker, New Haven Land Trust executive director. “But now, even with all the challenges, you see how far we’ve come.”
Since 1990, major agencies such as the state Department of Energy and Environmental Protection, have committed to cleaning up the Sound and restoring its ecosystem in collaboration with local municipalities and activists.
“The work that they’re doing, particularly in New Haven, connecting people to the Sound is really important,” Elicker said. “The history of the Sound is a lot of residents feared water. They think that the water is dirty and therefore don’t interact with the ocean. The report card shows we’ve come a long way since 30 years ago.”
The Central and Eastern Basins, which stretch from the Housatonic River to the Atlantic Ocean, have been consistently supportive of marine life over the 10-year analysis. The Western Basin around Bridgeport, extending to Stamford show improvement, going from a B rating to an A- rating. This area has shown the most notable improvement in water quality over the last decade, the report said.
The Western Narrows, the region around New York City, has seen improvement, but with such a dense population and large development it still suffers from the worst water quality with an F rating. The Eastern Narrows, which extends from Pelham Bay Park in New York to Stamford, have come a long way in the last decade. The water quality in this area has risen from a D+ to a B- rating. The dissolved oxygen levels there have improved through concentrated efforts to reduce nitrogen flowing into the Sound from fertilizers and sewage of roughly 500,000 septic systems in coastal communities
“We know from historical accounts that the waters of western Long Island Sound were once bountiful and nearly pristine and supported large eel grass meadows and fisheries,” said Jason Krumholz, a science adviser for the report card. “We know that if we commit the resources and effort to this task that we can once again again achieve healthy conditions throughout Long Island Sound.”
Water quality can be influenced year to year by weather and other factors, so scientists can’t establish accurate trends of water quality without looking at many years of data. With a 10-year retrospective analysis, scientists have evidence that dissolved oxygen levels have improved over the past 10 years because of coordinated conservation efforts.