Inorganic Nitrogen Deposition and Its Impacts on N:P-Ratios and Lake Productivity

Water

关键词: catchment;    lakes;    nitrogen deposition;    nitrate;    phosphorus;    stoichiometry;    productivity;   

DOI  :  10.3390/w5020327

来源: mdpi

【 摘 要 】

The pronounced increase in the cycling and deposition of biologically reactive dissolved inorganic nitrogen (DIN) over large areas globally not only cause increased concentrations of DIN in surface waters, but it will also affect nutrient ratios in rivers, lakes and coastal areas. This review addresses the flux and fate of DIN, focusing NO₃ in lakes of boreal and alpine catchments. Not only DIN-deposition, but also catchment properties strongly affect the concentrations of NO₃ in lakes, as well as NO₃:total P (TP) ratios. This ratio displays an extreme variability, and does also serve as an indicator of shift between N and P-limitation of aquatic autotrophs. A high share of forests and bogs in the catchment generally decreases NO₃:total P ratios, while alpine and subalpine catchments with sparse vegetation cover may have high NO₃:total P ratios, especially in regions with high DIN-deposition. Several empirical and experimental studies indicate a shift from an initial N to P-limitation, but for N-limited lakes, an increased growth of phytoplankton, periphytes and macrophytes may be accredited to elevated inputs of DIN. An intensified P-limitation may also be a consequence of elevated DIN-deposition. This P-limitation may again yield higher C:P-ratios in autotrophs with negative impacts on grazers and higher trophic levels.

【 授权许可】

CC BY   
© 2013 by the authors; licensee MDPI, Basel, Switzerland.