Chesapeake Bay water quality declines by four percentage points
"An estimated 38% of the Chesapeake Bay and its tidal tributaries met clean water standards for clarity, oxygen and algae growth between 2016 and 2018. This score is lower than the record high 42% from the previous reporting period, but is still the fifth highest estimate of water quality standards attainment since 1985. This four percentage point decrease is due in large part to a decline in dissolved oxygen in the open waters of the Bay, those areas beyond the shoreline and shallows. Dissolved oxygen is necessary for the survival of the Bay’s aquatic species, and is a factor in the annual dead zone. [...]"
Warming climate will impact dead zones in Chesapeake Bay
"In recent years, scientists have projected increasingly large summer dead zones in the Chesapeake Bay, areas where there is little or no oxygen for living things like crabs and fish to thrive, even as long-term efforts to reduce nutrient pollution continue. Researchers factored in local impacts of climate change to make projections of what the oxygen content of the Chesapeake Bay will look like in the future. [...]"
Source: Science Daily
Dead-zone report card reflects improving water quality in Chesapeake Bay
Dr. Marjy Friedrichs, a Virginia Institute of Marine Science professor and report card co-author, says "Even with environmental conditions that favor severe hypoxia, including record-high river input and light winds, our analysis shows that the total amount of hypoxia this year was within the normal range seen over the past 35 years."
An assessment of the predictability of column minimum dissolved oxygen concentrations in Chesapeake Bay using a machine learning model
"Subseasonal to seasonal forecasts have the potential to be a useful tool for managing estuarine fisheries and water quality, and with increasing skill at forecasting conditions at these time scales in the atmosphere and open ocean, skillful forecasts of estuarine salinity, temperature, and biogeochemistry may be possible. In this study, we use a machine learning model to assess the predictability of column minimum dissolved oxygen in Chesapeake Bay at a monthly time scale. [...]"
Source: Estuarine, Coastal and Shelf Science
Authors: Andrew C. Ross, Charles A. Stock
Chesapeake Bay: Larger-than-average summer 'dead zone' forecast for 2018 after wet spring
This summer's Chesapeake Bay hypoxic or dead zone, an area of low to no oxygen that can kill fish and other aquatic life, is expected to be about 1.9 cubic miles (7.9 cubic kilometers), according to the forecast released today by the two universities. [...]"
The competing impacts of climate change and nutrient reductions on dissolved oxygen in Chesapeake Bay
"The Chesapeake Bay region is projected to experience changes in temperature, sea level, and precipitation as a result of climate change. This research uses an estuarine-watershed hydrodynamic–biogeochemical modeling system along with projected mid-21st-century changes in temperature, freshwater flow, and sea level rise to explore the impact climate change may have on future Chesapeake Bay dissolved-oxygen (DO) concentrations and the potential success of nutrient reductions in attaining mandated estuarine water quality improvements. [...]"
Authors: Isaac D. Irby et al.
Chesapeake Bay dead zone this summer worst since 2014
In June, federal scientists predicted a bigger-than-average oxygen-deprived dead zone in the Chesapeake Bay this summer, and it turns out they were right.
Researchers with the Virginia Institute of Marine Science who study bay hypoxia announced Monday that the total amount of dead zones this summer was the worst since 2014, and a 10 percent increase over last year.
Source: Daily Press
Ocean Acidiﬁcation More Rapid in Coastal Oceans
"New research under the joint NCCOS Competitive Research Program and NOAA Ocean Acidification Program finds the combined effects of anthropogenic and biological carbon dioxide (CO2) inputs may lead to more rapid acidiﬁcation in Chesapeake Bay and other coastal water compared to the open ocean. The results indicate that eutrophication can exacerbate ocean acidification (OA) where animal and plant respiration contributes a far greater acidification in the coastal oceans relative to the open ocean. [...]"
Source: The National Centers for Ciastal Ocean Science
Acid zone in Chesapeake Bay identified
"Zone of water 30 feet below surface is increasing in acidity, threatening shellfish.
A research team, led by University of Delaware professor Wei-Jun Cai, has identified a zone of water that is increasing in acidity in the Chesapeake Bay.
The team analyzed little studied factors that play a role in ocean acidification (OA)--changes in water chemistry that threaten the ability of shellfish such as oysters, clams and scallops to create and maintain their shells, among other impacts."
Redox reactions and weak buffering capacity lead to acidification in the Chesapeake Bay
"The combined effects of anthropogenic and biological CO2 inputs may lead to more rapid acidification in coastal waters compared to the open ocean. It is less clear, however, how redox reactions would contribute to acidification. Here we report estuarine acidification dynamics based on oxygen, hydrogen sulfide (H2S), pH, dissolved inorganic carbon and total alkalinity data from the Chesapeake Bay, where anthropogenic nutrient inputs have led to eutrophication, hypoxia and anoxia, and low pH. [...]"
Source: Nature Communications
Authors: Wei-Jun Cai