Skip to main content

Large summer 'dead zone' forecast for Chesapeake Bay after wet winter and spring

Ecologists from the University of Maryland Center for Environmental Science and the University of Michigan are forecasting a large Chesapeake Bay "dead zone" in 2019 due to well-above-average river flows associated with increased rainfall in the watershed since last fall.
"The forecast this year reflects the high levels of precipitation that have been observed across the Bay's watershed," said report co-author Jeremy Testa of the University of Maryland Center for Environmental Science. "The high flows observed this spring, in combination with very high flows late last fall, are expected to result in large volumes of hypoxic and anoxic water."
The bay's hypoxic (low oxygen) and anoxic (no oxygen) zones are caused by excess nutrient pollution, primarily from agriculture and wastewater. The excess nutrients stimulate an overgrowth of algae, which then sinks and decomposes in the water. The resulting low oxygen levels are insufficient to support most marine life and habitats in near-bottom waters, threatening the bay's crabs, oysters and other fisheries.
This summer's Chesapeake Bay hypoxic or "dead zone," an area of low oxygen that can kill fish and other aquatic life, is expected to be about 2.1 cubic miles, while the volume of water with no oxygen is predicted to be between 0.49 and 0.63 cubic miles during early and late summer.
The predicted volumes are larger than the dead zone observed during the summer of 2018 and would be among the four largest in the past 20 years. Measurements of the Chesapeake Bay's dead zone go back to 1950, and the 30-year mean maximum dead zone volume is 1.74 cubic miles.
"The forecast is not surprising considering the near-record high flows in 2018 that have continued into 2019," said Bruce Michael, director of the Resource Assessment Service at the Maryland Department of Natural Resources. "That said, bottom dissolved oxygen concentrations are improving over the long-term in Maryland's portion of the Chesapeake Bay, indicating our efforts to reduce nutrient pollution throughout the entire watershed are improving water quality conditions, helping to support fish, shellfish and our aquatic resources."
The Maryland Department of Natural Resources will conduct bimonthly Bay water quality monitoring cruises June through August to track Bay summer hypoxia. Results from each monitoring cruise will be available on the Department's Eyes on the Bay website at http://eyesonthebay.dnr.maryland.gov/eyesonthebay/index.cfm
The University of Maryland Center for Environmental Science's Chesapeake Bay Report Card released earlier this spring gave the Bay a grade of "C" in 2018, in part due to the extreme precipitation. Spring rainfall plays an important role in determining the size of the Chesapeake Bay "dead zone." This year, exceptionally high spring rainfall and streamflow is transporting nitrogen to tidal waters in amounts above the long-term average, according to the U.S. Geological Survey, which provides the nitrogen-loading estimates used to generate the annual hypoxia forecast.
In spring 2019, the Susquehanna River delivered 102.6 million pounds of nitrogen into the Chesapeake Bay. The Potomac River, as measured near Washington, D.C., supplied an additional 47.7 million pounds of nitrogen, according to USGS. This is well-above long-term averages of 80.6 million pounds from the Susquehanna and 31.8 million pounds from the Potomac. Loads from the Susquehanna have not been this high since 2011.
"Managing estuarine responses to changing conditions on the landscape continues to be one of the nation's environmental challenges," said Joel Blomquist, hydrologist for the U.S. Geological Survey (USGS). "The science partnership in the Chesapeake Bay is setting the standard for supporting environmental managers with observation-based science."
"This year's forecast is for the fourth largest dead zone in the past 20 years, illustrating that more work needs to be done," said University of Michigan aquatic ecologist and report coauthor Don Scavia. "The Chesapeake Bay dead zone remains considerably larger than the reduction goals, and we'll never reach those targets unless more is done to reduce nutrient pollution."
The bay outlook is based on models developed at the University of Michigan and the University of Maryland Center for Environmental Science, with funding provided by the National Oceanic and Atmospheric Administration and data generated by the United States Geological Survey and Maryland Department of Natural Resources.
Throughout the year, researchers measure oxygen and nutrient levels as part of the Chesapeake Bay Monitoring Program, run by the Maryland Department of Natural Resources and the Virginia Department of Environmental Quality. This year's findings will be released in the fall.
Story Source:
Note: Content may be edited.

Comments

Post a Comment

Popular posts from this blog

Dark matter may be older than the Big Bang

Dark matter, which researchers believe make up about 80% of the universe's mass, is one of the most elusive mysteries in modern physics. What exactly it is and how it came to be is a mystery, but a new Johns Hopkins University study now suggests that dark matter may have existed before the Big Bang. The study, published August 7 in  Physical Review Letters , presents a new idea of how dark matter was born and how to identify it with astronomical observations. "The study revealed a new connection between particle physics and astronomy. If dark matter consists of new particles that were born before the Big Bang, they affect the way galaxies are distributed in the sky in a unique way. This connection may be used to reveal their identity and make conclusions about the times before the Big Bang too," says Tommi Tenkanen, a postdoctoral fellow in Physics and Astronomy at the Johns Hopkins University and the study's author. While not much is known about its origins,...
Post a Comment
Read more

Home births as safe as hospital births: International study suggests

A large international study led by McMaster University shows that low risk pregnant women who intend to give birth at home have no increased chance of the baby's perinatal or neonatal death compared to other low risk women who intend to give birth in a hospital. The results have been published by  The Lancet 's  EClinicalMedicine  journal. "More women in well-resourced countries are choosing birth at home, but concerns have persisted about their safety," said Eileen Hutton, professor emeritus of obstetrics and gynecology at McMaster, founding director of the McMaster Midwifery Research Centre and first author of the paper. "This research clearly demonstrates the risk is no different when the birth is intended to be at home or in hospital." The study examined the safety of place of birth by reporting on the risk of death at the time of birth or within the first four weeks, and found no clinically important or statistically different risk between home...
Post a Comment
Read more

GSAT-11 satellite to be launched from French Guiana on Dec 5th

GSAT-11 satellite to be launched from French Guiana on Dec 5th GSAT-11 would be located at 74 East and is the fore-runner in a series of advanced communications satellite with multi-spot beam antenna coverage over Indian mainland and Islands, ISRO said. GSAT-11 is the next generation “high throughput” communication satellite configured around ISRO’s I-6K Bus. (PTI/Representational). Indian space agency ISRO is scheduled to launch GSAT-11, the “heaviest” satellite built by it, on-board Ariane-5 rocket of Arianespace from French Guiana on December 5. Weighing about 5,854 kg, GSAT-11 would play a vital role in providing broadband services across the country, and also provide a platform to demonstrate new generation applications, the Indian Space Research Organisation (ISRO) said. It is the “heaviest” satellite built by ISRO, the space agency said. GSAT-11 is the next generation “high throughput” communication satellite configured around ISRO’s  I-6K Bus, and it...
Post a Comment
Read more