Human Alteration Of The Global Nitrogen Cycle - Issues In Ecology Back In 19freakin97

[hatrack]

Human activities are greatly increasing the amount of nitrogen cycling between the living world and the soil, water, and
atmosphere. In fact, humans have already doubled the rate of nitrogen entering the land-based nitrogen cycle, and that
rate is continuing to climb. This human-driven global change is having serious impacts on ecosystems around the world
because nitrogen is essential to living organisms and its availability plays a crucial role in the organization and functioning
of the world’s ecosystems. In many ecosystems on land and sea, the supply of nitrogen is a key factor controlling the
nature and diversity of plant life, the population dynamics of both grazing animals and their predators, and vital ecological
processes such as plant productivity and the cycling of carbon and soil minerals. This is true not only in wild or
unmanaged systems but in most croplands and forestry plantations as well. Excessive nitrogen additions can pollute
ecosystems and alter both their ecological functioning and the living communities they support.

Most of the human activities responsible for the increase in global nitrogen are local in scale, from the production and use
of nitrogen fertilizers to the burning of fossil fuels in automobiles, power generation plants, and industries. However,
human activities have not only increased the supply but enhanced the global movement of various forms of nitrogen
through air and water. Because of this increased mobility, excess nitrogen from human activities has serious and longterm
environmental consequences for large regions of the Earth.

The impacts of human domination of the nitrogen cycle that we have identified with certainty include:

· Increased global concentrations of nitrous oxide (N2O), a potent greenhouse gas, in the atmosphere as
well as increased regional concentrations of other oxides of nitrogen (including nitric oxide, NO) that
drive the formation of photochemical smog;
· Losses of soil nutrients such as calcium and potassium that are essential for long-term soil fertility;
· Substantial acidification of soils and of the waters of streams and lakes in several regions;
· Greatly increased transport of nitrogen by rivers into estuaries and coastal waters where it is a major
pollutant.

We are also confident that human alterations of the nitrogen cycle have:

· Accelerated losses of biological diversity, especially among plants adapted to low-nitrogen soils, and
subsequently, the animals and microbes that depend on these plants;
· Caused changes in the plant and animal life and ecological processes of estuarine and nearshore
ecosystems, and contributed to long-term declines in coastal marine fisheries.
National and international policies should attempt to reduce these impacts through the development and widespread
dissemination of more efficient fossil fuel combustion technologies and farm management practices that reduce the
burgeoning demand for and release of nitrogenous fertilizers.

EDIT

Human Alteration of the Global Nitrogen Cycle:
Causes and Consequences
Issues in Ecology Number 1 Spring 1997
2

EDIT

http://www.esa.org/science_resources/issues/FileEnglish/issue1.pdf

[n2doc]

1. We've known about these issues since at least the 1970's

Basicaly, we have doubled the amound of nitrogen entering the global ecosystem, including the oceans. This is messing up all sorts of things and causing all sorts of undesireable feedbacks, for example the increase in "dead zone" no oxygen areas in coastal oceans.

Carbon inputs get the most attention, but nutreint inputs also are important.

[ramapo]

2. No news here

n2doc is so correct. Most all of the major environmental issues have been known since the 1970s, the decade that saw the rise and fall of the environmental movement. That was when there was an opportunity to use our technology and talents to limit the human footprint.

Instead we went on a major binge and here we are....