Carbon freshwater

Much building material has been derived from two monomineral sedimentary rocks gypsum (composed of hydrated calcium sulfate) and limestone, which consists of calcite (composed mostly of calcium carbonate). Freshwater and seawater contain dissolved calcium carbonate and calcium sulfate. Most limestone and gypsum are formed when, as a consequence of the evaporation of water, calcium sulfate and calcium carbonate precipitate out of the water solutions as either gypsum or limestone. Limestone is also formed as a result of the activity of living organisms. Many sea- and freshwater animals, such as snails, clams, and corals, as well as some water plants, draw... 

I.E. Keeley, D.R. Sandquist (1992) Carbon Freshwater Riant. Riant Cell Environ. 15, 1012-1035... 

If poUed, most aquaculturists would probably indicate a preference for well water. Both freshwater and saline wells are common sources of water for aquaculture. The most commonly used pretreatments of well water include temperature alteration (either heating or cooling) aeration to add oxygen or to remove or oxidize such substances as carbon dioxide, hydrogen sulfide, and iron and increasing salinity (in mariculture systems). Pretreatment may also include adjusting pH, hardness, and alkalinity through the appHcation of appropriate chemicals. 

The most evident damage from acid depositions is to freshwater lake and stream ecosystems. Acid depositions can lower the pH of the water, with potentially serious consequences for fish, other animal, and plant life. Lakes in areas with soils containing only small amounts of calcium or magnesium carbonates that could help neutralize acidified rain are especially at risk. Few fish species can survive the sudden shifts in pH (and the effects of soluble... 

A number of freshwater lakes were surveyed for concentrations of plutonium, the ratio of its upper to lower oxidation states, pH, and the concentration of dissolved organic carbon (DOC), which are shown in Table 11(11). 

The case of bacterial reduction of sulfate to sulfide described by Berner (1984) provides a useful example. The dependence of sulfate reduction on sulfate concentration is shown in Fig. 5-4. Here we see that for [SO ] < 5 mM the rate is a linear function of sulfate concentration but for [SO4 ] > 10 itiM the rate is reasonably independent of sulfate concentration. The sulfate concentration in the ocean is about 28 mM and thus in shallow marine sediments the reduction rate does not depend on sulfate concentration. (The rate does depend on the concentration of organisms and the concentration of other necessary reactants - organic carbon in this case.) In freshwaters the sulfate concentration is... 

The freshwater cycle is an important link in the carbon cycle as an agent of erosion and as a necessary condition for terrestrial life. Although the amount of carbon stored in freshwater systems is insignificant as a carbon reservoir (De Vooys, 1979 Kempe, 1979a), about 90% of the material transported from land to oceans is carried by streams and rivers. 

Kempe, S. (1979a). Carbon in the freshwater cycle. In "The Global Carbon Cycle" (B. Bolin, E. T. Degens, S. Kempe and P. Ketner, eds), pp. 317-342. Wiley, New York. 

Rich JJ, GM King (1998) Carbon monoxide oxidation by bacteria associated with the roots of freshwater macrophytes. Appl Environ Microbiol 64 4939-4943. 

The martensitic alloys contain 12 to 20 percent chromium with controlled amounts of carbon and other additives. Type 410 is a typical member of this group. These alloys can be hardened by heat treatment, which can increase tensile strength from 550 to 1380 MPa (80,000 to 200,000 Ibf/in ). Corrosion resistance is inferior to that of austenitic stainless steels, and martensitic steels are generally used in mildly corrosive environments (atmospheric, freshwater, and organic exposures). In the hardened condition, these materials are very susceptible to hydrogen embrittlement. 

Copper compounds are used routinely and widely to control freshwater snails that serve as intermediate vectors of schistosomiasis and other diseases that afflict humans (Hasler 1949 NAS 1977 Rowe and Prince 1983 Winger etal. 1984 Al-Sabri etal. 1993). These compounds include copper sulfate, copper pentachlorophenate, copper carbonate, copper-tartaric acid, Paris green (copper arsenite-acetate), copper oxide, copper chloride, copper acetyl acetonate, copper dimethyl dithiocar-bamate, copper ricinoleate, and copper rosinate (Cheng 1979). Also, many species of oyster enemies are controlled by copper sulfate dips. All tested species of marine gastropods, tunicates, echinoderms, and crabs that had been dipped for 5 seconds in a saturated solution of copper sulfate died if held in air for as little as a few seconds to 8 h mussels, however, were resistant (MacKenzie 1961). 

Winberg, S., R. Bjerselius, E. Baatrup, and K.J. Doving. 1992. The effect of Cu(II) on the electro-olfactogram (EOG) of the Atlantic salmon (Salmo salar L) in artificial freshwater of varying inorganic carbon concentrations. Ecotoxicol. Environ. Safety 24 167-178. 

In water, the free zinc ion is thought to coordinate with six water molecules to form the octahedral aquo ion (Zn(H20)6)2+ in the absence of other complexing or adsorbing agents (Spear 1981). In freshwater, zinc exists almost exclusively as the aquo ion at pH >4 and <7 (Campbell and Stokes 1985). In freshwater at pH 6, the dominant forms of dissolved zinc are the free ion (98%) and zinc sulfate (2%) at pH 9 the dominant forms are the monohydroxide ion (78%), zinc carbonate (16%), and the free ion (6% USEPA 1987). In typical river waters, 90% of the zinc is present as aquo ion, and the remainder consists of ZnHC03+, ZnC03, and ZnS04 (Spear 1981). 

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