Nitrogen found in 75 per cent of wilderness lakes

Nitrogen pollution has been found in the vast majority of remote mountain lakes of Europe and the Rocky Mountains, spreading concern over the extent of the human carbon footprint.

The effects of pollution on remote forests, lands and lakes are largely unknown until now, as scientists have discovered traces of nitrogen pollution in three quarters of lakes in the northern hemisphere. Using an approach similar to aquatic archaeology, scientists monitored historical changes in chemical composition of bottom deposits in 36 lakes.

The results confirm the effects of increased use of nitrogen, through fossil fuels and agricultural fertilizers, with US Environmental Protection Agency projections showing that humans have already doubled the rate of nitrogen released to the biosphere since 1950. The chemical composition of the lakes is probably caused by atmospheric currents travelling from thousands of miles away.

Gordon Holtgrieve, a postdoctoral researcher at University of Washington School of Aquatic and Fishery Sciences said: “Our study is the first large-scale synthesis to demonstrate that biologically-active nitrogen associated with human society is being transported in the atmosphere to the most remote ecosystems on the planet.”

The evidence also provides an explicit chronology for entry of the Earth into the ‘Anthropocene’.