Concentrations of phosphorus and nitrogen in surface waters are being regulated in the United States and European Union. Human activity has raised the concentrations of these nutrients, leading to eutrophication of inland waters, which causes nuisance growth of algae and other aquatic plants. Control of phosphorus often has had the highest priority because of its presumed leading role in limiti...

Climate change is expected to bring about alterations in the marine physical and chemical environment that will induce changes in the concentration of dissolved CO(2) and in nutrient availability. These in turn are expected to affect the physiological performance of phytoplankton. In order to learn how phytoplankton respond to the predicted scenario of increased CO(2) and decreased nitrogen in ...

The capacity of bacteria for degrading dissolved organic nitrogen (DON) and remineralising ammonium is of importance for marine ecosystems, as nitrogen availability frequently limits productivity. Here, we assess the capacity of a widely distributed and metabolically versatile marine bacterium to degrade phytoplankton-derived dissolved organic carbon (DOC) and nitrogen. To achieve this, we lyse...

In the past decade a series of studies have shown that the active transport of inorganic carbon and nutrients by diel vertical migration of zooplankton is an important component of the biological pump. Less well known is how excretion of dissolved organic material (DOM) by migrating zooplankton enhances this export by creating a migratory DOM pump. We measured ammonia (NH4 ) and dissolved organ...

1. Although dissolved nutrients and the quality of particulate organic matter (POM) influence microbial processes in aquatic systems, these factors have rarely been considered simultaneously. We manipulated dissolved nutrient concentrations and POM type in three contiguous reaches (reference, nitrogen, nitrogen + phosphorus) of a low nutrient, thirdorder stream at Hubbard Brook Experimental For...

Ammonium (NH4 ), nitrate+nitrite (NOx), dissolved inorganic phosphorus (DIP) and dissolved organic carbon, nitrogen and phosphorus (DOC, DON and DOP) were measured in the Altamaha River and several tributaries during a two year period from September 2000 through September 2002. Temporal variations in concentration as well as nutrient and dissolved organic matter loading from the Altamaha to the...

Abstract In this study, changes in water quality characteristics were compared before and after the construction of eight multifunctional weirs Nakdong River Basin South Korea. A cluster analysis spatial variation showed that locations classified as Cluster 1 pre-construction (sites ND7 ND8) shifted into 2 post-construction, indicating types changed weirs. Principal component factor analyses re...

This study focused on water quality for Guanting Reservoir, the possible auxiliary drinking water source of Beijing. Through remote sensing (RS) approach, water quality retrieval models were established and analyzed for eight common concerned water quality variables, including algae content, turbidity, and concentrations of chemical oxygen demand, total nitrogen, ammonia nitrogen, nitrate nitro...