Concentration of dissolved phosphates and total phosphorus in seawater near the Cape Utrish, Black Sea

Dynamics of growth of natural phytoplankton and bacterioplankton in deep seawater upwelled to the upper sea layer were studied. Seawater from the lower part of the aerobic zone of the Black Sea was shown to have high bio-productive potential and can be used as an environment for algae and bacteria cultivation.

Isotope compositions of oxygen and carbon from phosphates and Fe-Mn crusts and nodules sampled at Pacific seamounts

Results of a study of phosphates collected on Pacific Ocean seamounts using some physicochemical methods are described. Particular attention is paid to isotopic studies of both phosphates and their accompanying features. Oxygen isotopic compositions in phosphates of different genetic types were compared. Possible hydrothermal origin of phosphates is considered, and probable conditions of their formation are determined.

Specific and high-affinity binding of inositol phosphates to an isolated pleckstrin homology domain.

Pleckstrin homology (PH) domains are found in many signaling molecules and are thought to be involved in specific intermolecular interactions. Their binding to several proteins and to membranes containing 1-alpha-phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2] has been reported. A region that includes the PH domain has also been implicated in binding of phospholipase C-delta 1 (PLC-delta 1) to both PtdIns(4,5)P2 and D-myo-inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] [Cifuentes, M. E., Delaney, T. & Rebecchi, M. J. (1994) J. Biol. Chem. 269, 1945-1948]. We report herein that the isolated PH domain from PLC-delta 1 binds to both PtdIns(4,5)P2 and Ins(1,4,5)P3 with high affinity and shows the same binding specificity seen by others with whole PLC-delta 1. Thus the PH domain is functionally and structurally modular. These results demonstrate stereo-specific high-affinity binding by an isolated PH domain and further support a functional role for PH domains in the regulation of PLC isoforms. Other PH domains did not bind strongly to the compounds tested, suggesting that inositol phosphates and phospholipids are not likely physiological ligands for all PH domains. Nonetheless, since all PH-domain-containing proteins are associated with membrane surfaces, several PH domains bind to specific sites on membranes, and PH domains appear to be electrostatically polarized, a possible general role for PH domains in membrane association is suggested.

(Table 1) Chemical composition of oceanic phosphates and their selenium content

Selenium content of phosphate material from the ocean bottom ranges from 0.2 to 4.7 mg/kg. Phosphorites of various ages from the Atlantic and Pacific Oceans contain 1.0-2.4 mg/kg of selenium, phosphatized coproliths 0.7-1.2 mg/kg, fish bones 0.2-1,4 mg/kg, and bones of marine mammals 0.5-4.7 mg/kg. Recent diatom muds on the shelf of Namibia are considerably enriched in selenium (12.2-13.8 mg/kg) than phosphorites that form within them. Accumulation of selenium in phosphate material on the ocean bottom results from diagenetic reduction, causing it to be precipitated from liquid phase and to concentrate in organic components and sulfides.

(Table 2) Oxygen isotope composition of authigenic and detrital phosphates from ODL Leg 201 sites

Many (bio)geochemical processes that bring about changes in sediment chemistry normally begin at the sediment-water interface, continue at depth within the sediment column and may persist throughout the lifetime of sediments. Because of the differential reactivity of sedimentary phosphate phases in response to diagenesis, dissolution/precipitation and biological cycling, the oxygen isotope ratios of phosphate (d18OP) can carry a distinct signature of these processes, as well as inform on the origin of specific P phases. Here, we present results of sequential sediment extraction (SEDEX) analyses combined with d18OP measurements, aimed at characterizing authigenic and detrital phosphate phases in continental margin sediments from three sites (Sites 1227, 1228 and 1229) along the Peru Margin collected during ODP Leg 201. Our results show that the amount of P in different reservoirs varies significantly in the upper 50 m of the sediment column, but with a consistent pattern, for example, detrital P is highest in siliciclastic-rich layers. The d18OP values of authigenic phosphate vary between 20.2 per mil and 24.8 per mil and can be classified into at least two major groups: authigenic phosphate precipitated at/near the sediment-water interface in equilibrium with paleo-water oxygen isotope ratios (d18Ow) and temperature, and phosphate derived from hydrolysis of organic matter (Porg) with subsequent incomplete to complete re-equlibration and precipitated deeper in the sediments column. The d18OP values of detrital phosphate, which vary from 7.7-15.4 per mil, suggest two possible terrigenous sources and their mixtures in different proportions: phosphate from igneous/metamorphic rocks and phosphate precipitated in source regions in equilibrium with d18Ow of meteoric water. More importantly, original isotopic compositions of at least one phase of authigenic phosphates and all detrital phosphates are not altered by diagenesis and other biogeochemical changes within the sediment column. These findings help to understand the origin and provenance of P phases and paleoenvironmental conditions at/near the sediment-water interface, and to infer post-depositional activities within the sediment column.

Effect of phosphates on water treatment : phosphates in Illinois surface waters /

"Final report for the period June 15, 1955 to September 15, 1957 for American Association of Soap and Glycerine Producers."

Effect of phosphates on water treatment : phase III. effects of phosphates on coagulation and sedimentation of turbid waters /

"Final report for the period June 15, 1955 to September 15, 1957 for American Association of Soap and Glycerine Producers."

Les combustibles minéraux, les minerais, et les phosphates en Algérie.

Mode of access: Internet.

The mineral industry of the British Empire and foreign countries. Statistics, 1920-1922. Phosphates.

At head of title: Imperial Mineral Resources Bureau.

The mineral industry of the British Empire and foreign countries. Statistics, 1919-1921. Phosphates.

At head of title: Imperial Mineral Resources Bureau.

Phosphoric acid, phosphates and phosphatic fertilizers.

Includes bibliographies.

Researches on the arseniates, phosphates, and modifications of phosphoric acid.

"Specially noteworthy on two different grounds--firstly, because in it the relations to each other of ortho-, pyro-, and metaphosphoric acids and the corresponding salts were first pointed out; and secondly, because it formed the starting point of the idea of the basicity of acids."--Editor's pref.