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.

Laboratory Development of Permeable Reactive Mixtures for the Removal of Phosphorus from Onsite Wastewater Disposal Systems

Abstract: Laboratory batch and column studies were conducted to develop permeable reactive mixtures to remove phosphorus from the effluent of onsite wastewater disposal systems. Mixtures can be placed in situ, as horizontal or vertical reactive barriers in sediments receiving wastewater discharge, or can be used in single pass, self-contained treatment modules in alternative treatment systems. Reactive mixtures composed of silica sand, high calcium crushed limestone, and readily available metal oxides were tested to evaluate phosphorus attenuation. Iron/calcium oxides, produced from steel manufacturing, and fine-grained activated aluminum oxide outperformed other oxides tested during batch experiments. These materials removed greater than 99% of PO4 from a 10 mg/L PO4−P solution within 1 h of contact. Long-term attenuation capacities of the mixtures were assessed by continually loading bench-scale columns with a 3.3 mg/L PO4−P solution, at representative groundwater flow rates. A column containing 50 wt % silica sa...

Phosphorus limitation of forest leaf area and net primary production on a highly weathered soil.

Abstract: We tested the hypothesis that P was the nutrient limiting net primary production of a nativeMetrosideros polymorpha forest on a highly weathered montane tropical soil in Hawaii. A factorial experiment used all combinations of three fertilizer treatments: nitrogen (N), phosphorus (P) and a mix of other essential nutrients (OE), consisting primarily of mineral derived cations and excluding N and P. P addition, but not N or OE, increased leaf area index within 12 months, foliar P concentration measured at 18 months, and stem diameter increment within 18 months. Stem growth at 18 months was even greater when trees fertilized with P also received the OE treatment. N and P additions increased leaf litterfall and N and P in combination further increased litterfall. The sequence of responses suggests that increased available P promoted an increase in photosynthetic area which led to increased wood production. P was the essential element most limiting to primary production on old volcanic soil in contrast to the N limitation found on young volcanic soils.

Effect of broadcast manure on runoff phosphorus concentrations over successive rainfall events.

Abstract: Concern over eutrophication has directed attention to manure management effects on phosphorus (P) loss in runoff. This study evaluates the effects of manure application rate and type on runoff P concentrations from two, acidic agricultural soils over successive runoff events. Soils were packed into 100- x 20- x 5-cm runoff boxes and broadcast with three manures (dairy, Bos taurus, layer poultry, Gallus gallus; swine, Sus scrofa) at six rates, from 0 to 150 kg total phosphorus (TP) ha(-1). Simulated rainfall (70 mm h(-1)) was applied until 30 min of runoff was collected 3, 10, and 24 d after manure application. Application rate was related to runoff P (r2 = 0.50-0.98), due to increased concentrations of dissolved reactive phosphorus (DRP) in runoff; as application rate increased, so did the contribution of DRP to runoff TP. Varied concentrations of water-extractable phosphorus (WEP) in manures (2-8 g WEP kg(-1)) resulted in significantly lower DRP concentrations in runoff from dairy manure treatments (0.4-2.2 mg DRP L(-1)) than from poultry (0.3-32.5 mg DRP L(-1)) and swine manure treatments (0.3-22.7 mg DRP L(-1)). Differences in runoff DRP concentrations related to manure type and application rate were diminished by repeated rainfall events, probably as a result of manure P translocation into the soil and removal of applied P by runoff. Differential erosion of broadcast manure caused significant differences in runoff TP concentrations between soils. Results highlight the important, but transient, role of soluble P in manure on runoff P, and point to the interactive effects of management and soils on runoff P losses.

Migrating haemulid fishes as a source of nutrients and organic matter on coral reefs1

Abstract: Juvenile french and white grunts (Haemulon jlavolineatum and Haemulon plumierl) rest over coral colonies during the day and feed only at night in surrounding seagrass beds. We examined the amount of nitrogen, phosphorus, particulate organic carbon, and calories which these fishes deposited over the coral colonies that were their resting sites. Weight-specific rates of nitrogen excretion by grunts decreased with increasing fish size. Rates of phosphorus excretion were not related to fish size. Excretory products were rich in nitrogen (molar N:P = 48), primarily ammonium, whereas fecal material was richer in phosphorus (N:P = 8). Feces leached over half of their phosphorus content within the first day. Half of the daily excretion and defecation occurred during the first 4 h after grunts returned to the reef, in which time they doubled the amount of NH.,+ available to corals under calm conditions. Seasonal patterns of nutrient and particulate organic carbon (caloric) input to coral colonies varied with grunt biomass on the colony. The maximum input to colonies of Porites jiircata from grunts occurred during August, which coincided with the time of highest coral growth rate. Grunts deposited an average of 164 and 251 mg m-2 d-’ of particulate organic carbon (feces) on the P. furcata and Acropora palmata colonies over which they rested, an energy supplement to the colonies of 0.8 and 1.2 kcal m-2 d-l. Rates of nutrient and organic matter input from grunts are comparable to or greater than rates observed in other naturally or artificially enriched ecosystems.