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.

C, N, P and S in Rivers: From Sources to Global Inputs

Abstract: Carbon, nitrogen, phosphorus and sulfur are essential elements found either as dissolved or particulate river-borne material. Their origins, their behaviours in aquatic systems, the occurrence of their specific forms, and the rates of transport by rivers are first considered in this paper. The anthropogenic influences on riverine C, N, P, and S are briefly presented. Finally the global fluvial budgets of the specific forms, including the anthropogenic loads are estimated.

Hydrocarbon production from secondarily treated piggery wastewater by the green alga Botryococcus braunii

Abstract: A laboratory study was conducted on the removal of nitrogen and phosphorus from piggery wastewater during growth of Botryococcus braunii UTEX 572, together with measurements of hydrocarbon formation by the alga. The influence was tested of the initial nitrogen and phosphorus concentration on the optimum concentration range for a culture in secondarily treated piggery wastewater. A high cell density (> 7 g L−1 d. wt) was obtained with 510 mg L−1 NO3-N. Growth increased with nitrogen concentration at the basal phosphorus concentration (14 mg P L−1). The growth rate was nearly independent (μ = 0.027 ∼ 0.030 h−1) of the initial phosphate concentration, except under conditions of phosphate deficiency (μ = 0.019 h−1). B. braunii grew well in piggery wastewater pretreated by a membrane bioreactor (MBR) with acidogenic fermentation. A dry cell weight of 8.5 mgL−1 and hydrocarbon level of 0.95 gL−1 were obtained, and nitrate was removed at a rate of 620 mg NL−1. These results indicate that pretreated piggery wastewater provides a good culture medium for the growth and hydrocarbon production by B. braunii.

A Comparison of the Structure, Primary Productivity, and Transpiration of Cypress Ecosystems in Florida

Abstract: To investigate how inputs of water and nutrients influence the structural and functional characteristics of cypress wetlands, primary productivity, respiration, transpiration, tree growth, biomass, basal area, stem density, standing stocks of phosphorus, and litterfall were measured in several kinds of Florida cypress ecosystems subjected to varying inflows of water and nutrients. A scrub cypress forest, natural and sewage-enriched cypress domes, and a cypress floodplain forest were studied. Floodwaters in these ecosystems ranged from stagnant and phosphorus poor (0.01-0.08 mg P/L) to flowing and phosphorus rich (0.66-5.86 mg P/L). Inputs of total phosphorus transported by water to these forests varied from 0.11 g P m-2 yr-1 in the scrub cypress forest to 1625 g P m-2 yr-1 in the floodplain forest. Phosphorus content of aboveground biomass (ranging from 0.25 to 4.78 g P/M2) appeared to be positively related to phosphorus inputs. Biomass and other structural characteristics of the study sites appeared to be related to stand history rather than to phosphorus inputs. For example, there was little difference in aboveground biomass between natural cypress domes (20.6-26.6 kg/M2), a sewage-enriched dome (21.7 kg/M2), and a floodplain forest (28.4 kg/M2). Aboveground biomass for the scrub cypress forest was low (3.6 kg/ m2). Net daytime photosynthesis (2.1-13.7 g C.m-2 ground surface d-1), plant respiration (0.9-10.9 g C m-2 ground surface .d-1) and an estimate of gross primary productivity increased with increasing inputs of total phosphorus. Aboveground biomass production (sum of wood production, ranging from 44 to 1080 g.m-2 yr-1, and litterfall, ranging from 224 to 941 g m-2 yr-1) increased with increasing total phosphorus inputs in the low range, but biomass production leveled in the high input range. Total water loss from cypress forests increased with increasing P inputs. Mean daily transpiration rates from the scrub cypress forest (1.0 mm) and cypress domes (3.1-3.8 mm) were lower while those from the floodplain forest (5.6 mm) were similar to evaporation rates from open water bodies. Ratios of transpiration to net daytime photosynthesis were also low (156-221 g H20/g organic matter), showing that cypress is efficient in its water use. In cypress domes and scrub cypress forest, where water may be limiting, trees appear to adjust to potential water stress through leaf morphology adaptations and minimum canopy development (leaf area index, LAI = 0.53-3.4 m2/m2). When water is not potentially limiting, as in the floodplain forest, adaptations to conserve water were lacking (e.g., LAI = 8.5 m2/m2). A dome with added sewage effluent had higher leaf biomass, leaf area index, and chlorophyll a content, and more phosphorus stored in leaves than untreated domes. Net primary productivity, litter production, and wood production increased approximately twofold over pre-effluent rates or untreated cypress domes.