Connections Between Food, Water Pollution and Dead Zones
Fertilizers used on crops and manure from livestock can both runoff into waterways where the nitrogen and phosphorus they contain contribute to algal blooms, eutrophication and dead zones. Nitrogen and phosphorus can be carried hundreds of miles from their source to dead zone areas where they are concentrated. The most famous dead zone in the United States is just off the coast of Louisiana. This portion of the Gulf of Mexico is just below the outlet of the Mississippi River. The nitrogen and phosphorus which causes the dead zone is the result of what happens in the areas which drain into the Mississippi River. The Mississippi watershed drains most of the United States and that the area within this watershed is a major farming area contributing nitrogen and phosphorus which is concentrated in the Gulf of Mexico dead zone. The Dead Zones for Dinner lesson explores these issues while reinforcing key national science standards.
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- Michael Wittman
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From the ancient Amazonian Indians: A modern weapon against global warming.
Unlike familiar charcoal briquettes, BIOCHAR is charcoal made from wood, grass and other organic matter, and has the potential to help slow climate change.
Scientists are reporting that "biochar" -- a material that the Amazonian Indians used to enhance soil fertility centuries ago — has potential in the modern world to help slow global climate change. Mass production of biochar could capture and sock away carbon that otherwise would wind up in the atmosphere as carbon dioxide, the main greenhouse gas. Biochar reduces runoff of fertilizers by a great degree and can be a big factor in mitigating dead zones down stream from farming interests. Their report appears in ACS' Environmental Science & Technology.
Kelli Roberts and colleagues note that biochar is charcoal produced by heating wood, grass, cornstalks or other organic matter in the absence of oxygen. The heat drives off gases that can be collected and burned to produce energy. It leaves behind charcoal rich in carbon. Amazonian Indians mixed a combination of charcoal and organic matter into the soil to improve soil fertility, a fact that got the scientists interested in studying biochar's modern potential.
The study involved a "life-cycle analysis" of biochar production, a comprehensive cradle-to-grave look at its potential in fighting global climate change and all the possible consequences of using the material. It concludes that several biochar production systems have the potential for being an economically viable way of sequestering carbon — permanently storing it — while producing renewable energy and enhancing soil fertility.
- November 18, 2011, 8:26 AM
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