Earth's water cycle is changing as result of global warming and other factors. (Credit: U.S. Geological Survey)What do the Gulf of Mexico’s “dead zone,” global climate change and acid rain have in common? They’re all a result of human impacts to Earth’s biology, chemistry and geology, and the natural cycles that involve all three.

On August 4-5, 2009, scientists who study such cycles – biogeochemists — will convene at a special series of sessions at the Ecological Society of America (ESA)’s 94th annual meeting in Albuquerque, N.M. … A biogeochemical cycle is a pathway by which a chemical element, such as carbon, or compound, like water, moves through Earth’s biosphere, atmosphere, hydrosphere and lithosphere. … Researchers are discovering that biogeochemical cycles — whether the water cycle, the nitrogen cycle, the carbon cycle, or others — happen in concert with one another. Biogeochemical cycles are “coupled” to each other and to Earth’s physical features. … Now, with global warming and other planet-wide impacts, biogeochemical cycles are being drastically altered. Like broken gears in machinery that was once finely-tuned, these cycles are falling out of sync. … The “dead zone” in the Gulf of Mexico is one example. Nitrogen-based fertilizers make their way from Iowa cornfields to the Mississippi River, where they are transported to the Gulf of Mexico. Once deposited in the Gulf, nitrogen stimulates algal blooms. When the algae die, their decomposition consumes oxygen, creating an area of water roughly the size of New Jersey that is inhospitable to aquatic life. Protecting the Gulf’s fisheries–with an estimated annual value of half-a-billion dollars–relies on understanding how coupled biogeochemical cycles interact. …

Earth’s Biogeochemical Cycles, Once In Concert, Falling Out Of Sync