Earth’s nitrogen cycle profoundly affected by humans

Posted on January 18, 2012 by Bob Berwyn

Nitrogen pollution affects wide range of land, sea ecosystems

Even high mountain lakes are feeling the sting of nitrogen pollution.

By Summit Voice

SUMMIT COUNTY — Nitrogen pollution is becoming one of the most pervasive global environmental problems, with nutrient pollution from agricultural runoff and sewage leading to coral diseases, bird die-offs, fish diseases, human diarrheal diseases and vector-borne infections transmitted by insects such as mosquitos and ticks.

About two-thirds of U.S. coastal systems are moderately to severely impaired due to nutrient loading and there are now nearly 300 hypoxic (low oxygen) zones along the U.S. coastline.

Air pollution continues to reduce biodiversity, with exotic, invasive species dominating native species that are sensitive to excess reactive nitrogen. For example, in California, airborne nitrogen is impacting one third of the state’s natural land areas,  and the expansion of nitrogen-loving, non-native, highly flammable grasses in the western U.S. has increased fire risk in the region.

These conclusions are part of a sobering assessment by a multi-disciplinary team of scientists led by Eric Davidson of the Woods Hole Research Center who reviewed the major sources of reactive nitrogen in the U.S., resulting effects on health and the environment, and potential solutions. (more…)

Filed under: agriculture, Environment, rivers, Summit County news, water, wetlands | Tagged: , , , , , | Leave a Comment »

Expanding ocean dead zones threaten valuable fisheries

Posted on December 11, 2011 by Bob Berwyn

Expanding dead zones is shrinking habitat for billfish like blue marlin and other species.

Blue marlin found to avoid low-oxygen areas in wide-ranging study

By Summit Voice

SUMMIT COUNTY — Ever-growing oxygen-starved areas in the Atlantic are shrinking habitat for high value fish like marlins, according to new research by NOAA fisheries biologist Eric Prince.

According to the study, climate change is one of the key factors in the expansion of the so-called dead zones. As they grow, marlins, other billfish and tunas move into surface waters where they are more vulnerable to fishing.

The researchers tagged a number of blue marlin and tracked their movement in relation to the location of known dead zones. They found blue marlins venturing deeper when dissolved oxygen levels are higher and remaining in shallower surface waters when low dissolved oxygen areas encroach on their habitat from below. Blue marlins and many other billfish are high-energy fish that need large amounts of dissolved oxygen. (more…)

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Environment: Gulf dead zone could be the largest ever

Posted on June 19, 2011 by Jenney Coberly

2011 hypoxic zone to be affected by extreme Mississippi River flooding

2010 Gulf of Mexico hypoxic zone showing dissolved oxygen contours. Click on the map to go to the NOAA hypoxia watch page.

By Summit Voice

SUMMIT COUNTY — The 2011 hypoxic dead zone zone in the Gulf of Mexico is predicted to be the largest ever recorded due to extreme flooding of the Mississippi River this spring, according to an annual forecast by a team of NOAA-supported scientists from the Louisiana Universities Marine Consortium, Louisiana State University and the University of Michigan.

Along with replenishing soil in the river corridor, the massive flooding washes enormous amounts of nutrients to the sea. Seventy percent of nutrient loads that cause hypoxia are a result of agricultural runoff caused by rain washing fertilizer off of the land and into streams and rivers. Additionally, 12 million people live in urban areas that border the Mississippi, and these areas constantly discharge treated sewage into rivers.

Scientists are predicting the dead zone could measure between 8,500 and 9,421 square miles, or an area about the size of New Hampshire.  If it does reach those levels it will be the largest since mapping of the Gulf dead zone began in 1985. The largest hypoxic zone measured to date occurred in 2002 and encompassed more than 8,400 square miles.

“While there is some uncertainty regarding the size, position and timing of this year’s hypoxic zone in the Gulf, the forecast models are in overall agreement that hypoxia will be larger than we have typically seen in recent years,” said Jane Lubchenco, Ph.D., under secretary of commerce for oceans and atmosphere and NOAA administrator.

(more…)

Filed under: Environment, Marine biology | Tagged: , , , , , , , | 6 Comments »

Ocean dead zones now spread over 95,000 square miles

Posted on January 21, 2011 by Bob Berwyn

New website serves as clearinghouse for growing environmental issue

Ocean dead zones have spread around the planet in the past 50 years.

By Summit Voice

SUMMIT COUNTY — Ocean dead zones with low oxygen levels have spread during the last 50 years to encompass about 95,000 square miles — about the size of New Zealand.

“These dead zones, or oxygen deserts, are very damaging to the environment and also to people that rely on the sea for their livelihood,” said Professor Bob Diaz, of the Virginia Institute of Marine Science, announcing the completion of a new one-stop website that will serve as a clearinghouse for science and mapping of the damaged areas. Click here to visit the new website. (more…)

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Hypoxic ‘dead zone’ found off Pacific Northwest coast

Posted on September 4, 2010 by Bob Berwyn

Federal report documents more than 300 areas where marine life is affected

A map shows where acute hypoxia — low oxygen levels in the water — affects marine life.

By Bob Berwyn

SUMMIT COUNTY — We are pouring so many pollutants into our streams and rivers that acute incidents of hypoxia have increased 30-fold since the 1960s, the U.S. government concluded in a new report released this week.

Hypoxia is a condition in which oxygen levels drop so low that fish and other animals are stressed or killed. The areas affected by hypoxia are known as dead zones, and because of the biological chemistry of those growing areas, they are even becoming a growing factor in global warming.

The research also documented a hypoxic area in the Pacific, off the coast of Oregon and Washington. The area is the third-largest dead zone in the world, behind the Gulf of Mexico and the Baltic Sea, and it may be linked to global warming, according to EPA administrator Lisa Jackson.

The report carefully catalogues more than 300 U.S. coastal zones affected by hypoxia, as well as some of the efforts to address the issue. (more…)

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Ocean ‘dead zones’ contribute to global warming

Posted on March 18, 2010 by Bob Berwyn

A NASA map shows the location of major ocean dead zones. Scientists say those areas may contribute significant amounts of greenhouse gases to the atmosphere.

As oxygen-deprived waters increase, they emit more greenhouse gasses into atmosphere

By Bob Berwyn

SUMMIT COUNTY — Growing marine dead zones along the world’s coasts are intensifying global warming effects by releasing nitrous oxide into the atmosphere, University of Maryland researchers concluded in a study published in the March 12 edition of the journal Science.

The research shows how global warming can create a feedback loop that intensifies itself with impacts on various systems.

University of Maryland Center for Environmental Science oceanographer Dr. Lou Codispoti said  low-oxygen waters can elevate concentrations of nitrous oxide in the atmosphere, exacerbating the impacts of global warming and contributing to ozone holes that cause an increase in harmful UV radiation.

“As the volume of hypoxic waters move towards the sea surface and expands along our coasts, their ability to produce the greenhouse gas nitrous oxide increases,” said Dr. Codispoti. “With low-oxygen waters currently producing about half of the ocean’s net nitrous oxide, we could see an additional significant atmospheric increase if these dead zones continue to expand.”

The dead zones themselves are caused by a variety of factors, including rising global temperatures and pollution from industry and agriculture. (more…)

Filed under: global warming | Tagged: , , , | 1 Comment »

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