Phosphorus Dynamics in Dingle Marsh, Idaho

Phosphorus mass-balance studies of Dingle Marsh, Idaho indicated that the marsh was an annual net sink for total suspended sol ids and all forms of phosphorus under consideration: total phosphorus, particulate phosphorus, total dissolved phosphorus, dissolved organic phosphorus, and orthophosphate phosphorus. During some months, however, more phosphorus was exported from the marsh than entered. Phosphorus mass-balance dynamics were compared between night and day. Total suspended solids and particulate phosphorus dynamics were controlled by sedimentation of particulate material, a physical process, and were unaffected by light conditions. Dissolved organic and ortho-phosphorus were affected by light conditions indicating, at least indirectly, that biological processes were affecting dissolved phosphorus dynamics. These phosphorus fractions were occasionally released in large amounts by the marsh at night. An in situ enclosure experiment was performed to determine major sites of phosphorus uptake/release. A twentyfour-hour rate of particulate phosphorus decrease in the enclosures could be predicted (r2=0.89) by knowing the initial concentration of total suspended solids. On a twentyfour-hour basis, periphyton, detritus, and live bulrushes tended to remove more dissolved organic phosphorus from the water than they added to it while plankton and sediments added dissolved organic phosphorus to the water. Orthophosphates were removed from the water by plankton, detritus, and periphyton with plankton dominating the changes. Live bulrushes or sediments within the bulrush system tended to be a source for orthophosphates. The open water ecosystem was a greater net source for dissolved organic phosphorus than the bulrush system. The open water system was a greater net sink, however, for orthophosphates, than was the bulrush community

Sorption and fractionation of dissolved organic matter and associated phosphorus in agricultural soil

Molibility of dissolved organic matter (DOM) strongly affects the export of nitrogen (N) and phosphorus (P) from oils to surface waters. To study the sorption an mobility of dissolved organic C and P (DOC, DOP) in soil, the pH-dependent sorption of DOM to samples from Ap, EB, and Bt horizons from a Danish agircultural Humic Hapludult was investigated and a kinetic model applicable in field-scale model tested. Sorption experiments of 1 to 72 h duration were conducted at two pH levels (pH 5.0 and 7.0) and six initial DOC concentrtions (0-4.7 mmol L-1). Most sorption/desorption occurred during the first few hours. Dissolved organic carbon and DOP sorption decreased strongly with increased pH and desorption dominated at pH 7, especially for DOC. Due to fractionation during DOM sorption/desorption at DOC concentrations up to 2 mmol L-1, the solution fraction of DOM was enriched in P indicating preferred leaching of DOP. The kinetics of sorption was expressed as a function of how far the solution DOC or DOP concentrations deviate from "equilibrium". The model was able to simulate the kinetics of DOC and DOP sorption/desorption at all concentrations investigated and at both pH levels making it useful for incorporation in field-scale models for quantifying DOC and DOP dynamics

Cycling of dissolved organic phosphorus compounds in natural waters

U.S. Department of the InteriorU.S. Geological SurveyOpe

Iron Oxide Nanoparticles: An Inorganic Phosphatase

Phosphorus is one of the most important macronutrients for the primary production. The transformation of dissolved organic phosphorus in the environment and its contribution to biological production in the different ecosystems is still a mystery. Recently, it was demonstrated that phosphate ester can be rapidly hydrolyzed in solutions containing iron oxide nanoparticles with enzyme kinetics. The catalyst is sensitive to temperature and pH changes and inhibited by tetrahedral oxyanions with an order of PO4 < MoO4 < WO4. The oxo-Fe structure in the iron oxide nanoparticles, like the metal center of natural phosphatase (e.g., purple acid phosphatase, PAP), might contribute to the observed catalytic activity. Iron oxide nanoparticles are very common and widely exist in the current earth environment, and phosphate esters are the main component of dissolved organic phosphorus in soil and waters. It is expected that iron oxide nanoparticles in aqueous environments, as an inorganic phosphatase, play a critical role for the phosphorus transformation from the view of the phosphorus cycle

Determining inorganic and organic phosphorus

The original version of this chapter was revised. The correction to this chapter is available at https://doi.org/10.1007/7651_2019_253Phosphorus (P) is a macronutrient for all microalgal species, and the main form of uptake is as orthophosphate (PO4). In this chapter we present a colorimetric method for determining the PO4 concentration and dissolved organic phosphorus (DOP) based on total phosphorus (TP) measurements. We also describe a method for determining particulate organic phosphorus (POP) based on the same principles.Peer reviewe

Concentrations and Uptake of Dissolved Organic Phosphorus Compounds in the Baltic Sea

The dissolved organic phosphorus (DOP) pool in marine waters contains a variety of different compounds. Knowledge of the distribution and utilization of DOP by phyto- and bacterioplankton is limited, but critical to our understanding of the marine phosphorus cycle. In the Baltic Sea, detailed information about the composition of DOP and its turnover is lacking. This study reports the concentrations and uptake rates of DOP compounds, namely, adenosine triphosphate (dATP), deoxyribonucleic acid (dDNA), and phospholipids (dPL), in the Baltic Proper and in Finnish coastal waters in the summers of 2011 and 2012. Both areas differed in their dissolved inorganic phosphorus (DIP) concentrations (0.16 and 0.02–0.04 μM), in the C:P (123–178) and N:P (18–27) ratios, and in abundances of filamentous cyanobacteria and of autotrophic and heterotrophic picoplankton. The mean concentrations of dATP-P, dDNA-P, and dPL-P were 4.3–6.4, 0.05–0.12, and 1.9–6.8 nM, respectively, together contributing between 2.4 and 5.2% of the total DOP concentration. The concentrations of the compounds varied between and within the investigated regions and the distribution patterns of the individual components are not linked to each other. DIP was taken up at rates of 10.1–380.8 nM d-1. dATP-P and dDNA-P were consumed simultaneously with DIP at rates of 6.9–24.1 and 0.09–0.19 nM d-1, respectively, with the main proportion taken up by the size fraction <3 μm and with DIP to be the dominant source. Groups of hydrographical and biological parameters were identified in the multiple regression analysis to impact the concentrations and uptake rates. It points to the complexity of the regulation. Our results indicate that the investigated DOP compounds, particularly dATP-P, can make significant contributions to the P nutrition of microorganisms and their use seems to be not intertwined. Therefore, more detailed knowledge of all DOP components including variation of concentrations and the utilization is required to understand the roles of DOP in marine ecosystems

Sargasso Sea phosphorus biogeochemistry : an important role for dissolved organic phosphorus (DOP)

© The Authors, 2010. This article is distributed under the terms of the Creative Commons Attribution 3.0 License. The definitive version was published in Biogeosciences 7 (2010): 695-710, doi: 10.5194/bg-7-695-2010Inorganic phosphorus (SRP) concentrations in the subtropical North Atlantic are some of the lowest in the global ocean and have been hypothesized to constrain primary production. Based upon data from several transect cruises in this region, it has been hypothesized that dissolved organic phosphorus (DOP) supports a significant fraction of primary production in the subtropical North Atlantic. In this study, a time-series of phosphorus biogeochemistry is presented for the Bermuda Atlantic Time-series Study site, including rates of phosphorus export. Most parameters have a seasonal pattern, although year-over-year variability in the seasonal pattern is substantial, likely due to differences in external forcing. Suspended particulate phosphorus exhibits a seasonal maximum during the spring bloom, despite the absence of a seasonal peak in SRP. However, DOP concentrations are at an annual maximum prior to the winter/spring bloom and decline over the course of the spring bloom while whole community alkaline phosphatase activities are highest. As a result of DOP bioavailability, the growth of particles during the spring bloom occurs in Redfield proportions, though particles exported from the euphotic zone show rapid and significant remineralization of phosphorus within the first 50 m below the euphotic zone. Based upon DOP data from transect cruises in this region, the southward cross gyral flux of DOP is estimated to support ~25% of annual primary production and ~100% of phosphorus export. These estimates are consistent with other research in the subtropical North Atlantic and reinforce the hypothesis that while the subtropics may be phosphorus stressed (a physiological response to low inorganic phosphorus), utilization of the DOP pool allows production and accumulation of microbial biomass at Redfield proportions.This research was supported by the NSF Biological Oceanography Program through awards OCE-0453023 (MWL), OCE-0451419 (STD), OCE-0452904 (JWA). We also acknowledge support for the Bermuda Atlantic Time-series Study provided by the NSF Chemical and Biological Oceanography Programs through the most recent awards OCE 0326885 and OCE 0752366. CS thanks The Charrock Foundation and Princeton Environmental Institute for her support

Dissolved Organic Phosphorus Production during Simulated Phytoplankton Blooms in a Coastal Upwelling System

Dissolved organic phosphorus (DOP) is increasingly recognized as an important phosphorus source to marine primary producers. Despite its importance, the production rate and fate of DOP is poorly understood. In this study, patterns of DOP production were evaluated by tracking the evolution of DOP during simulated phytoplankton blooms initiated with nutrient amended surface waters, relative to controls, from the Oregon (USA) coastal upwelling system. Nitrogen (N) and phosphorus (P) additions were used to decouple DOP production and hydrolysis by inducing or repressing, respectively, community alkaline phosphatase activity. In order to examine the progression of nutrient uptake and DOP production under upwelling versus relaxation conditions, two experiments were initiated with waters collected during upwelling events, and two with waters collected during relaxation events. Maximum [under (+P) conditions] and minimum [under (+N) conditions] DOP production rates were calculated and applied to in situ DOP levels to evaluate which end-member rate most closely approximates the in situ DOP production rate at the four study sites in this coastal system. Increases in DOP concentration occurred by day-5 in control treatments in all experiments. N treatments displayed increased chlorophyll a, increased alkaline phosphatase activity, and yielded lower net DOP production rates relative to controls, suggesting that DOP levels were depressed as a consequence of increased hydrolysis of bioavailable DOP substrates. Phosphorus additions resulted in a significant net production of DOP at all stations, but no increase in chlorophyll a relative to control treatments. The contrasting patterns in DOP production between treatments suggests that changes in the ambient dissolved inorganic nitrogen:dissolved inorganic phosphorus (DIN:DIP) ratio could exert profound control over DOP production rates in this system. Patterns of DOP production across the different experiments also suggest that bathymetry-driven differences in water residence times can influence DOP cycling. Taken together, these factors may impact the potential export of DOP to offshore ecosystems