Nitrogen: too much of a vital resource

The WWF science brief with lead author Jan Willem Erisman (Professor Integrated Nitrogen Studies, Earth and Climate Cluster) provides an in-depth overview of the nitrogen challenge.

05/12/2015 | 11:26 AM

It also explores options to decrease the negative impacts of excess nitrogen on biodiversity and ecosystems, while at the same time providing food security to a growing world population. Potential solutions comprise increasing nitrogen use efficiency in agriculture, reducing waste in the food chain, promoting diets with less animal protein in developed countries and a shift from fossil fuels to renewable energy sources such as solar and wind energy.

Excess nitrogen originating from chemical fertilizers, animal manure and burning of fossil fuels, are increasingly affecting soil, water and air quality. In coastal and marine ecosystems, excess nitrogen levels cause eutrophication. “An estimated 500 estuaries worldwide have turned into ‘dead zones’,” says Jan Willem Erisman. “Much of the terrestrial biodiversity is created as a result of limitations in nitrogen: organisms have adapted to the natural nitrogen poor environments in a wide variety of ways,” he adds. Excess nitrogen levels will change species composition in favour of fewer species that can withstand or thrive in these circumstances. 40% of the protected areas in the world have exceeded critical levels of nitrogen above which there is a risk of biodiversity loss.

World hypoxic and eutrophic coastal areas
Figure 1: World hypoxic and eutrophic coastal areas The map shows three types of eutrophic zones: Documented hypoxic areas – Areas with scientific evidence that hypoxia was caused, at least in part, by an overabundance of nitrogen and phosphorus. Hypoxic areas have oxygen levels low enough to inhibit the existence of marine life. Areas of concern – Systems that exhibit effects of eutrophication. These systems are possibly at risk of developing hypoxia. Systems in recovery – Areas that once exhibited low dissolved oxygen levels and hypoxia, but are now improving. Source: rs.resalliance.org/2008/01/28/mapping-coastal-eutrophication/

However, nitrogen also plays an important role in food security. The human creation of chemical nitrogen fertilizer has enabled the production of more food and a change to more protein rich diets. It has been estimated that without chemical nitrogen fertilizer, only 3 billion people would have enough food given current diets and agricultural practices. That’s less than halve of the current global population.

In recognition of the urgent need to address this issue, WWF Netherlands has funded the Professorship of Integrated Nitrogen Studies within the Faculty of Earth and Life Sciences, currently held by prof. dr. Jan Willem Erisman. The Science Brief Nitrogen: too much of a vital resource aims to give a state-of-the-art on the nitrogen issues.

Nitrogen Cascade