Phosphorus

About: Phosphorus is a research topic. Over the lifetime, 53120 publications have been published within this topic receiving 939731 citations. The topic is also known as: element 15 & P.

Marine nitrogen: Phosphorus stoichiometry and the global N:P cycle

Abstract: Nitrogen supply is often assumed to limit marine primary production A global analysis of total nitrogen (N) to phosphorus (P) molar ratios shows that total N:P is low (<16:1) in some estuarine and coastal ecosystems, but up to 100:1 in open oceans This implies that elements other than N may limit marine production, except in human impacted, estuarine or coastal ecosystems This pattern may reconcile conflicting enrichment studies, because N addition frequently increases phytoplankton growth where total N:P is expected to be low, but P, Fe, or Si augment phytoplankton growth in waters where total N:P is high Comparison of total N:P stoichiometry between marine and freshwaters yields a model of the form of the aquatic N:P cycle

Long-term effects of forestry managements on water quality and loading in brooks

Abstract: The concentration of suspended solids in a meso-eutrophic basin remained unchanged in the years following clear felling (1983-85). The amount of suspended solids increased upon ditching, ploughing and mounting to a mean level of 81.8 mg l -1 in 1986-88, decreased to a level of 7.8 mg l -1 for 1989-91 and 4.5 mg l -1 for 1992-94. Total phosphorus concentration increased four-fold (142 μg l -1 ) in 1983-85 following clear felling, and remained at three times the reference concentration (95.4 μg l -1 ) in 1986-88 following ditching and site preparation. Phosphate phosphorus concentration increased more than five-fold after clear felling (97.8 μg l -1 ) in 1983-85 and was more than two-fold the reference (39.5 μg l -1 ) following ditching and site preparation in 1986-88. The concentrations of total phosphorus and phosphate phosphorus returned to the level recorded in a natural slate by 1989 onwards. Total nitrogen concentrations doubled (965 μg l -1 ) upon clear felling, and remained the same after ditching and site preparation in 1986-88. Where a protective strip of forest was left between the felling site and the brook, suspended solid did no increase in response to either clear felling or ploughing of the felled area, nor were any changes observed in total phosphorus, phosphate phosphorus or nitrogen componds. The ditching of peatland down to the level of the mineral soil led to an increase in the suspended solid concentration (17.8 mg l -1 ) by a factor of more than 12 in the first three years (1983-85) and by a factor of more than four (5.7 mg l -1 ) in the following three years (1986-88) compared with the reference period. Total nitrogen, nitrate and nitrite concentrations of ground water were markedly low all the time the forests remained in their natural state, but began to rise gradually following clear felling. A high increase was recorded as a consequence of ditching and site preparation.