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.

Photochemical transformation of allochthonous organic matter provides bioavailable nutrients in a humic lake

Abstract: Carbon, nitrogen and phosphorus associated with dissolved organic matter (DOM) form a large potential source of nutrients and energy for bacterio- and phytoplankton. The role of solar radiation in the transformation of DOM into inorganic and bioavailable forms was investigated in a humic boreal Lake Valkea-Kotinen. The concentrations of nitrate+nitrite, inorganic phosphorus and inorganic carbon increased, but those of ammonium decreased in <0.2-μm filtered hypolimnetic water during 1-day exposures to solar radiation. In epilimnetic water, solar radiation increased the concentration of ammonium at a rate equivalent to the rate of atmospheric deposition of inorganic nitrogen. When indigenous bacteria of Lake Valkea-Kotinen were inoculated into sunlight-exposed waters, bacteria achieved higher biovolume and productivity and incorporated carbon, nitrogen and phosphorus at greater rates than those grown in non-exposed waters. Bacteria mineralized dissolved organic carbon 92-375 % more in exposed than in non-exposed waters. Thus, in addition to direct photochemical mineralization, solar radiation increased metabolic mineralization of organic carbon by bacteria. Solar radiation decreased the activity of phosphomonoesterase during exposures down to <1% of the initial values. However, after 4-d bioassay the activity of phosphomonoestrase in the exposed waters exceeded that in the non-exposed water. Results showed that solar radiation transformed dissolved organic nitrogen, phosphorus and carbon into forms readily available to phyto- and bacterioplankton. The photochemical supply of nutrients increased the production of bacterioplankton and can be expected also to increase production of phytoplankton.

Impacts of biomass burning emissions and land use change on Amazonian atmospheric phosphorus cycling and deposition

Abstract: Phosphorus (P) availability constrains both carbon uptake and loss in some of the world's most productive ecosystems. In some of these regions, atmospheric aerosols appear to be an important, if not dominant, source of new P inputs. For example, previous work suggests that mineral aerosols from North Africa bring significant amounts of new phosphorus to the P-impoverished soils of the Amazon Basin. Here we use recent observations and atmospheric transport modeling to show that the Amazon Basin itself appears to be losing atmospheric phosphorus to neighboring regions as a consequence of biomass burning emissions, anthropogenic sources of mineral aerosols and primary biogenic particles. Observations suggest that biomass burning emissions and human disturbance are responsible for ∼23% of the phosphorus flux in the Amazon. Although biomass burning and disturbance may bring new phosphorus into nondisturbed regions, as a whole the Amazon appears to be losing phosphorus through the atmosphere. Phosphorus lost via atmospheric transport from the Amazon is deposited in the adjacent oceans and in other regions downwind. These results suggest that land use change within the Amazon may substantially increase phosphorus availability to the remaining undisturbed forests, and that this fertilization mechanism could potentially contribute to recent changes in carbon uptake measured in undisturbed stands, as well as fertilizing downwind ocean regions.

Effect of iron plaque outside roots on nutrient uptake by rice (Oryza sativa L.): Phosphorus uptake

Abstract: Under anaerobic conditions, ferric hydroxide deposits on the surface of rice roots have been shown to affect the uptake of some nutrients. In the present experiment, different amount of this iron plaque were induced on the roots of rice (Oryza sativa L. cv. TZ88-145) by supplying different Fe(OH)3 concentrations in nutrient solutions, and the effect of the iron plaque on phosphorus uptake was investigated. Results showed that 1) iron plaque adsorbed phosphorus from the growth medium, and that the amount of phosphorus adsorbed by the plaque was correlated with the amount of plaque; 2) the phosphorus concentration in the shoot increased by up to 72% after 72 h at concentration of Fe(OH)3 in the nutrient solution from 0 to 30 mg Fe/L, corresponding with amounts of iron plaque from 0.2 to 24.5 mg g-1 (root d. wt); 3) the phosphorus concentration in the shoots of rice with iron plaque was higher than that without iron plaque though the concentration in the shoot decreased when Fe(OH)3 was added at 50 mg Fe/L producing 28.3 mg g-1 (root d. wt) of plaque; and 4) the phosphorus concentrations in Fe-deficient and Fe-sufficient rice plants with iron plaque were the same, although phytosiderophores were released from the Fe-deficient roots. The phytosiderophores evidently did not mobilise phosphorus adsorbed on plaque. The results suggest that iron plaque on rice plant roots might be considered a phosphorus reservoir.

Mechanisms for internal loading of phosphorus in lakes

Abstract: Lake sediments play an important role in the phosphorus metabolism in lakes. The impact depends on the tendencies to retain and to release phosphorus.The internal loading will often determine the eutrophication status of the lake and the time lag for recovery after reduction of the external loading. Internal loading is most important during the summer. The potential source of phosphorus in the surficial sediments is very large in comparison to the pools in the water column. This means that even if only a very small amount is released, it will have significant impact on the phosphorus concentration in the lake water. The distribution of phosphorus forms in sediments have been investigated since the 1950s. Generally, vertical profiles of sediment phosphorus content, expressed on dry weight basis, show an increasing total content towards the sediment surface. The vertical profile continues up into the water when looking at the particulate matter. A number of environmental factors are important in the mobilisation processes. Most studies indicate that sediment bacteria have a significant role in uptake, storage and release of phosphorus including anaerobic release of iron-bound phosphorus. Several phytoplankton species have resting stages overwintering on the sediment. When growth is induced, they leave their habitat in order to shift their life-form to a pelagic one. In Lake Erken the cyanobacteria Gloeotrichia echinulata has been shown to contribute significantly to the internal loading of phosphorus during the summer.

Growth of benthic freshwater algae on dairy manures

Abstract: A potential alternative to land application of livestock manures for cropproduction is the production of algae to recover the nitrogen andphosphorus present in the manure. Compared to terrestrial plants,filamentous algae have exceedingly high growth and nutrient uptake rates. Moreover, they are capable of year-round growth in temperate climates,can be harvested on adapted farm-scale equipment, and yield a biomassthat should be valuable as an animal feed supplement. The objective of thisresearch was to evaluate algal turf scrubber (ATS) technology to removenitrogen, phosphorus and chemical oxygen demand from raw andanaerobically digested dairy manure. Laboratory-scale ATS units wereoperated by continuously recycling wastewater and adding manure effluentsdaily. ATS units were seeded with algal consortia from a nearby streamand grown using dairy manures from two different dairy farms. Algalbiomass was harvested weekly and dried prior to analysis for total Kjeldahlnitrogen, total phosphorus, and inorganic constituents. Wastewater sampleswere analyzed for total Kjeldahl nitrogen, ammonium, nitrate,orthophosphate, conductivity and chemical oxygen demand. Using atypical manure input containing 0.6–0.96 g total nitrogen day-1,the dried algal yield was approximately 5 g m-2 day-1. Thedried algae contained approximately 1.5–2% phosphorus and 5–7%nitrogen. Algal nitrogen and phosphorus accounted for 42–100% ofinput ammonium-nitrogen (33–42% of total nitrogen) and 58–100%of input total phosphorus, respectively.