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Posts Tagged ‘nutrients’

What Causes Oxygen to be Used Up In Deep Waters?

by February 26, 2012

ANSWER (CURRENTLY UNDER REVIEW): Bacteria use up the oxygen in the process of breaking down organic matter, like the waste from tiny animals and dead algae. This answer is focused on coastal ocean waters, but generally applies to deep waters in estuaries, ponds, lakes, and slow-moving stretches of rivers.
 

Q001 how oxygen is used up in deep waters v04

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Monitoring Will Be Key As Minnesota Takes A Leadership Role in Managing Nutrient Runoff

by January 18, 2012

5223892647_2a55e1b7c2 Yesterday I had the opportunity to hear EPA Administrator Lisa Jackson speak at the University of Minnesota, who was in town to launch a new program along with Minnesota’s Governor Mark Dayton and USDA secretary Tom Vilsack. The new initiative, Minnesota Agricultural Water Quality Certification Program, has a goal of reducing the introduction of nutrients and soils to waterways via runoff, a process known as “non-point source pollution” (a point source is a pipe, a sewage treatment plant, etc.).

I was drawn to the talk specifically to hear what Administrator Jackson would say about the new program, which I had read about in the morning’s Minneapolis StarTribune. She did not disappoint, although the bit about this new program occurred just as the questioning period came to a close. It was clear that she has a good deal of enthusiasm about this new program and its prospects for helping to reduce pollution, such as the introduction of nitrogen into the Mississippi that can lead to low-oxygen conditions in the Gulf of Mexico. (more…)

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A Billion Dollars Flowing Down the Mississippi Annually

by December 20, 2011

In a recent post, I did a bit of research to update the picture of nutrient flows down the Mississippi due to runoff and other sources in its watershed. There’s been an ongoing debate about the source of the nutrients in the river that are directly linked to low-oxygen conditions in the Gulf of Mexico.

For a taste of the debate, check out the controversy a year ago surrounding the premier of Troubled Waters, A Mississippi River Story (link to view on Twin Cities Public TV). Among other activity, there was a heated back-and-forth on the opinion pages of the Minneapolis Star Tribune (first piece arguing that research for film was dubious, counter piece by producers about the research behind the film). The flare up nearly squelched the premier, although it ultimately took place.

Personally, I experienced how difficult it can be to establish a “consensus view” of how to describe nitrogen flows for the report on ecosystem indicators described in my previous post. There was a constant tension throughout the report process to “tell readers what to do with the information” rather than just “giving them the facts.” I believe we ultimately struck a good balance, however, we nearly had resignations of participants when we unintentionally pushed the line on the indicator dealing with the movement of nitrogen and got too close to pointing fingers. (more…)

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Anything New in the Story of Nitrogen Moving into the Gulf of Mexico?

by December 14, 2011

Dialogue Earth has roots in a broad, stakeholder-based national report on the condition and use of U.S. ecosystems published by the Heinz Center in Washington, D.C. (the report is available in hard-copy from Island Press). Curiosity about the ongoing relevance of these indicators has led me to dive in and see what, if anything, can be said about trends since the release of the report in 2008.

The first indicator in the spotlight is one that describes the movement of nitrogen (N) into major waterways, through run-off as well as point discharges such as sewage treatment facilities (here’s a link to download a pdf of the indicator). Why is this an important indicator of the state of U.S. ecosystems? Our explanation in the report does a good job of answering this question:

Nitrogen is an important plant nutrient and is essential to all life. Nitrogen is an abundant component of the earth’s atmosphere, but it is unavailable to most life in gaseous form. In order to be used by plants and other organisms, nitrogen gas must be “fixed,” or converted to a “reactive” form, that plants can use, such as nitrate. Nitrogen is fixed and accumulates in ecosystems through natural processes, such as the growth of nitrogen-fixing plants like clover and soybeans. However, human activity has greatly increased the amount of reactive nitrogen added to ecosystems. The largest human-caused input of nitrogen to ecosystems comes from the conversion of atmospheric nitrogen gas into fertilizers. Additional reactive nitrogen gas is produced by the combustion of fossil fuels. Reactive nitrogen from all these sources can ultimately enter streams and rivers. Excess nitrogen transported to coastal waters by rivers can lead to low oxygen conditions, threaten fish and animal life, and degrade coastal water quality. (more…)

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