Coastal ecologists and managers have frequently used nitrogen stable isotopes (delta15N) to trace and monitor sources of anthropogenic nitrogen (N) in coastal ecosystems. However, the interpretation of delta15N data can often be challenging, as the isotope values fractionate substantially due to preferential retention and uptake by biota. There is a growing body of evidence that carbon isotopes...

Human-induced eutrophication degrades freshwater systems worldwide by reducing water quality and altering ecosystem structure and function. We compared current total nitrogen (TN) and phosphorus (TP) concentrations for the U.S. Environmental Protection Agency nutrient ecoregions with estimated reference conditions. In all nutrient ecoregions, current median TN and TP values for rivers and lakes...

Human-induced eutrophication degrades freshwater systems worldwide by reducing water quality and altering ecosystem structure and function. We compared current total nitrogen (TN) and phosphorus (TP) concentrations for the U.S. Environmental Protection Agency nutrient ecoregions with estimated reference conditions. In all nutrient ecoregions, current median TN and TP values for rivers and lakes...

Mycorrhizal associations are generally favourable for vascular plants in nutrient-poor conditions. Still, non-mycorrhizal plants are common in high arctic and alpine areas, which are often poor in nitrogen and phosphorus. The relative proportion of mycorrhizal plants has been found to decrease along with increasing altitude, suggesting that the advantage of the mycorrhizal symbiosis may change ...

BACKGROUND In Sweden, school meals are served free of charge and Swedish law states that school meals must be nutritious. Nevertheless, data on children's energy and nutrient intake from school meals are scarce. OBJECTIVE The aim was to describe the contribution of school meals to Swedish children's nutrient and energy intake during weekdays and compare this to the reference values based on t...

interrupting the processes which control ecosystem resources has dramatic impacts on the rangeland conditions. to protect ecosystems and landscape, it needs to understand the ecosystem processes which regulate the ecosystem resources. as main components of ecosystems, patches and inter-patches play important roles in energy and materials cascade. ecologically, functional parameters such as stab...