URI_Research_Magazine_2011-2012_Melissa-McCarthy

Working Hard to Protect Rhode Island Waters

When more than a million juvenile menhaden fish suddenly washed up dead on the shore of Greenwich Bay one hot August day in 2003, the question was why? Candace Oviatt, a professor of oceanography at the University of Rhode Island’s (URI) Graduate School of Oceanography (GSO), helped to determine the cause. Lack of oxygen, or hypoxia, was the reason for the disturbing fish kill, Oviatt said. In the days leading up to that August day, when the baby menhaden blanketed the shores of Greenwich and Apponaug coves, tests showed oxygen levels had plummeted in Greenwich Bay. In addition to menhaden, hypoxia can be lethal for other fish species and clams as well. The economic consequences of a fish kill can be devastating. To better understand this phenomenon, Oviatt has led a research project since 2005, which has examined nutrient pollution, water circulation patterns and other factors that can deplete Rhode Island’s coastal waters of its vitally important oxygen supply. Funded with $2.5 million from the National Oceanic and Atmospheric Administration’s (NOAA) Coastal Hypoxia Research Program, the

study used a 3-D computer model to track how water moves in and out of Narragansett Bay. Oviatt’s team also examined cores of sediment to determine the Bay’s historical oxygen conditions as well as the role stratification (layering) plays in hypoxic events. “All of us at URI have worked hard to improve the Bay over the years,” said Oviatt, whose office in the Marine Ecosystems Research Laboratory (MERL) on the University’s Bay Campus overlooks Narragansett Bay. Clean Rhode Island waters, whether it’s Narragansett Bay or the ocean beyond, are essential not only for the state’s fishermen, but also for the thousands of residents and tourists, who use the Bay for economic and recreational purposes, she said. After the Greenwich Bay fish kill, Rhode Island passed a law which substantially reduces the amount of nitrogen large wastewater facilities can discharge into the Bay. Nitrogen pollution, like stratification, is believed to be a factor in fish kills. In part, as a result of that law, the health of Narragansett Bay has improved in recent years, a significant development for the state’s shell fishermen. But, at the same time, climate change has caused the Bay to become

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