Background Knowledge of biological and climatic controls in terrestrial nitrogen (N) cycling
within and across ecosystems is central to understanding global patterns of key ecosystem …

Nitrogen is a requisite and highly demanded element for living organisms on Earth.
However, increasing human activities have greatly altered the global nitrogen cycle …

Nitrate (NO3−) concentrations in public water supplies have risen above acceptable levels
in many areas of the world, largely as a result of overuse of fertilizers and contamination by …

Nonpoint source nitrogen (N) pollution is a leading contributor to US water quality
impairments. We combined watershed N mass balances and stable isotopes to investigate …

Nitrate concentration in most aquifers in arid and semi-arid areas has increased in the past
several decades as a result of human activities. Under the predominantly oxic conditions of …

Recent advances in stable isotope measurements now allow for detailed investigations of
the sources, transformations, and deposition of reactive nitrogen (N) species. Stable …

Denitrification removes fixed nitrogen (N) from the biosphere, thereby restricting the
availability of this key limiting nutrient for terrestrial plant productivity. This microbially driven …

The discovery of the first chemically produced mass-independent isotope effect in 1983 by
Thiemens & Heidenreich opened a broad variety of applications, including physical …

Empirical critical loads for N deposition effects and maps showing areas projected to be in
exceedance of the critical load (CL) are given for seven major vegetation types in California …

Although increasing atmospheric nitrous oxide (N2O) has been linked to nitrogen loading,
predicting emissions remains difficult, in part due to challenges in disentangling diverse …