Nitrogen pollution of the world's oceans is harming marine ecosystems and
contributing to global warming, report two reviews published in the journal
Science.
The research, which involved dozens of scientists from around the world, shows
that human activity is dramatically altering nitrogen cycles in Earth's oceans,
soils, and atmosphere. The papers report that agricultural runoff and the
burning of fossil fuels have boosted the supply of reactive nitrogen in the open
oceans 50 percent above the normal range.
The first paper, led by Robert Duce of Texas A&M University, found that nitrogen
produced by human activity is responsible for about a third of the nitrous oxide
and a tenth of the carbon dioxide input to the world's oceans each year. The
researchers say the excess nitrogen "can deplete essential oxygen levels in the
water and has significant effects on climate, food production, and ecosystems
all over the world," according to a statement from Science.
Duce and colleagues calculate that humans account for up to three percent of the
new marine biological production annually. While the increased biological
activity sequesters CO2 from the ...