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 …

Soil microorganisms play important roles in nitrogen cycling within forest ecosystems.
Current research has revealed that a wider variety of microorganisms, with unexpected …

New techniques have identified a wide range of organisms with the capacity to carry out
biological nitrogen fixation (BNF)—greatly expanding our appreciation of the diversity and …

Atmospheric nitrogen (N) deposition is a recognized threat to plant diversity in temperate
and northern parts of Europe and North America. This paper assesses evidence from field …

Stable isotope analysis (SIA) has proven to be a useful tool in reconstructing diets,
characterizing trophic relationships, elucidating patterns of resource allocation, and …

This paper contrasts the natural and anthropogenic controls on the conversion of unreactive
N 2 to more reactive forms of nitrogen (Nr). A variety of data sets are used to construct global …

Extracellular enzymes are the proximate agents of organic matter decomposition and
measures of these activities can be used as indicators of microbial nutrient demand. We …

Nitrogen isotopic studies have the potential to shed light on the structure of ancient
ecosystems, agropastoral regimes, and human-environment interactions. Until relatively …

The relative activities of soil enzymes involved in mineralizing organic carbon (C), nitrogen
(N), and phosphorus (P) reveal stoichiometric and energetic constraints on microbial …

Anthropogenic nitrogen (N) deposition has accelerated terrestrial N cycling at regional and
global scales, causing nutrient imbalance in many natural and seminatural ecosystems …