Weathering phosphorus

The simulated change in the different soil phosphorus fractions (occluded, non-occluded mineral (labile plus sorbed), primary and organic) with time (Fig. 15.5b) show that volcanic ash parent phosphorus weathers quite rapidly during the first... 

This is the principal linkage between cyanobacterial blooms and eutrophication. Avoidance of cyanobacterial production does not necessarily depend upon eliminating all phosphorus inputs, but upon ensuring that optimum physical and chemical conditions for these organisms do not coincide. It is easy to understand why the biggest blooms in the UK have been in fertile lakes and reservoirs after prolonged spells of warm, dry weather in summer. 

It has been argued that phosphorus limits oceanic productivity on the million year time scale (Broecker, 1971). The reason is that essentially all phosphorus in the ocean is introduced by rivers and thus ultimately from the weathering of continental rocks. This flux is, in effect. 

Let us now determine the functional and dynamic characteristics of the fluxes of phosphorus (Table 4.4) based on analysis of existing ideas about their nature. The atmospheric cycle is governed by rock weathering, volcanic eruptions, and by the leaching of phosphorus by precipitation. From available estimates, the content of phosphorus in the lithosphere constitutes 0.093%, and the processes of weathering deliver annually to the atmosphere from 0.67 mgPcm 3 yr 1 to 5.06mgPcm-3 yr-1. Every year, volcanic eruptions contribute to the atmosphere about 0.2 106 tP. Since these processes are complicated and stochastic in nature and their models are absent, as a first approximation fluxes H and //f9 can be considered constant. 

Aluminum hydroxide is used in stomach antacids (including Maalox , Mylanta , and Delcid ), as a desiccant powder in antiperspirants and dentifrices in packaging materials as a chemical intermediate as a filler in plastics, rubber, cosmetics, and paper as a soft abrasive for brass and plastics as a glass additive to increase mechanical strength and resistance to thermal shock, weathering, and chemicals and in ceramics (HSDB 1995). Aluminum hydroxide is also used pharmaceutically to lower the plasma phosphorus levels of patients with renal failure (Budavari et al. 1989 Sax and Lewis 1987). 

To begin the discussion, we will present briefly a view of the modern carbon cycle, with emphasis on processes, fluxes, reservoirs, and the "CO2 problem". In Chapter 4 we introduced this "problem" here it is developed further. We will then investigate the rock cycle and the sedimentary cycles of those elements most intimately involved with carbon. Weathering processes and source minerals, basalt-seawater reactions, and present-day sinks and oceanic balances of Ca, Mg, and C will be emphasized. The modern cycles of organic carbon, phosphorus, nitrogen, sulfur, and strontium are presented, and in Chapter 10 linked to those of Ca, Mg, and inorganic C. In conclusion in Chapter 10, aspects of the historical geochemistry of the carbon cycle are discussed, and tied to the evolution of Earth s surface environment. 

Dissolve 16 parts gum-arabic in the least possible quantity of water, and mix with it 9 parts phosphorus iu powder (see No. 4338) then add 14 parts nitre (saltpetre), and 16 parts of either vermilion (red sulphuret of mercury), or binoxide (black oxide) of manganese, aud form the whole into a paste. Dip the matches into this pasto, and then let them dry. When quite dry they are to be dipped into a very dilute copal or lac varnish, and again dried by this means they are less likely to suffer from damp weather. 

Blooms of blue-green algae occur in appropriate weather conditions in still or slow-flowing bodies of water with high phosphorus concentrations that either occur naturally or are from a number of possible human-made sources. 

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