News

Chesapeake Bay: Larger-than-average summer 'dead zone' forecast for 2018 after wet spring

"Ecologists from the University of Michigan and the University of Maryland Center for Environmental Science are forecasting a larger-than-average Chesapeake Bay "dead zone" in 2018, due to increased rainfall in the watershed this 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. [...]"

Source: Phys.org

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Gulf of Mexico 'dead zone' forecasted to exceed the size of Connecticut

"Scientists have predicted the dead zone, or area with little to no oxygen in the northern Gulf of Mexico, will become larger than the state of Connecticut by the end of July. The dead zone will cover about 6,620 square miles of the bottom of the continental shelf off Louisiana and Texas. While there are more than 500 dead zones around the world, the northern Gulf of Mexico dead zone is the second largest human-caused coastal hypoxic area in the world."

Source: Phys.org

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Physical controls on oxygen distribution and denitrification potential in the north west Arabian Sea

Abstract.

"At suboxic oxygen concentrations, key biogeochemical cycles change and denitrification becomes the dominant remineralization pathway. Earth system models predict oxygen loss across most ocean basins in the next century; oxygen minimum zones near suboxia may become suboxic and therefore denitrifying. Using an ocean glider survey and historical data, we show oxygen loss in the Gulf of Oman (from 6‐12 to < 2 μmol kg‐1) not represented in climatologies. [...]"

Source: Grophysical Research Letters
Authors: B. Y. Queste et al.
DOI: 10.1029/2017GL076666

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Growing 'dead zone' confirmed by underwater robots in the Gulf of Oman

"New research reveals a growing 'dead zone' in the Gulf of Oman. Little data has been collected in the area for almost 50 years because of piracy and geopolitical tensions. The area devoid of oxygen was confirmed by underwater robots. Reasearchers found an area larger than Scotland with almost no oxygen left. The environmental disaster is worse than expected with dire consequences for fish and marine plants, plus humans who rely on the oceans for food and employment. "

Source: Science Daily

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Nancy Rabalais - The "dead zone" of the Gulf of Mexico

"Ocean expert Nancy Rabalais tracks the ominously named "dead zone" in the Gulf of Mexico -- where there isn't enough oxygen in the water to support life. The Gulf has the second largest dead zone in the world; on top of killing fish and crustaceans, it's also killing fisheries in these waters. Rabalais tells us about what's causing it -- and how we can reverse its harmful effects and restore one of America's natural treasures."

Watch the full TED Talk here.


Gulf of Mexico dead zone not expected to shrink anytime soon

"Achieving water quality goals for the Gulf of Mexico may take decades, according to findings by researchers at the University of Waterloo.

The results, which appear in Science, suggest that policy goals for reducing the size of the northern Gulf of Mexico's dead zone may be unrealistic, and that major changes in agricultural and river management practices may be necessary to achieve the desired improvements in water quality.

The transport of large quantities of nitrogen from rivers and streams across the North American corn belt has been linked to the development of a large dead zone in the northern Gulf of Mexico, where massive algal blooms lead to oxygen depletion, making it difficult for marine life to survive.

"Despite the investment of large amounts of money in recent years to improve water quality, the area of last year's dead zone was more than 22,000 km2—about the size of the state of New Jersey," said Kimberly Van Meter, lead author of the paper and a postdoctoral fellow in the Department of Earth and Environmental Sciences at Waterloo. [...]"

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Dealing with Dead Zones: Hypoxia in the Ocean

When water runs off of farmland and urban centers and flows into our streams and rivers, it is often chock-full of fertilizers and other nutrients. These massive loads of nutrients eventually end up in our coastal ocean, fueling a chain of events that can lead to hypoxic "dead zones" — areas along the sea floor where oxygen is so low it can no longer sustain marine life. In this episode, we're joined by NOAA scientist Alan Lewitus to explore why dead zones form, how the problem of hypoxia is growing worse, and what we're doing about it.

Source: National Oceanic and Atmospheric Administration (NOAA)
Author: Troy Kitch

Read the full article here.


Earth’s Oceans Suffocate as Climate Change and Nutrient Loading Create “Dead Zones”

"A new research study from a Global Ocean Oxygen Network (GO2NE) team of scientists reveals that the number of low- and zero oxygen sites in the world’s oceans have increased dramatically in the past 50 years. The Intergovernmental Oceanographic Commission of the United Nations created the GO2NE working group to provide a multidisciplinary, global view of deoxygenation, with the end goal of advising policymakers on preserving marine resources by countering low oxygen. [...]"

Source: environmental monitor
Author: Karla Lant

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Gulf of Mexico Battles Expanding Dead Zone in Louisiana

"During the summer of 2017, researchers with the Louisiana Universities Marine Consortium (LUMCON) and Louisiana State University mapped the largest dead zone in the Gulf of Mexico to date.

The Gulf of Mexico meets the shorelines of Alabama, Louisiana, Mississippi, Texas and western Florida and is home to a large fishing industry. Several rivers from the Midwestern watershed flow south into the Gulf, carrying with them sediment, nutrient loads, and pollution from fossil fuel burning and wastewater systems.
The problem isn’t new, but it is expanding. "

Author: Mindy Cooper
Source: Environmental Monitor

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A Giant Blob of Floodwater From Harvey Is Still Moving Through the Gulf

"The rain began on August 25, and it would fall, remarkably, for four more days. We know now that Hurricane Harvey dumped as much as 60 inches of rain over parts of Texas. Twenty trillion gallons in all. The equivalent of the entire Chesapeake Bay. Enough to push the Earth’s crust down two centimeters. [...]

What oceanographers do know about the interface of freshwater and ocean comes from studying rivers that naturally empty into the sea. The key is density. Because freshwater lacks dissolved salt, it is less dense and floats atop seawater. It becomes a barrier between the air and the ocean water, which can have nasty consequences. “The freshwater sitting on the salty water cuts off the oxygen from the atmosphere getting into the ocean, and then you get the dead zone,” says Steve DiMarco [...]"

Source: The Atlantic

Read the full article here.


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