Oceans control

This chapter overlaps considerably with the only two others from this Treatise I have had the pleasure to read Chapters 6.04 and 6.19. My chapter is distinguished, I suppose, by the perspective of a geochemical ocean modeler, attempting to integrate new field observations into the context of the ocean control of the pco of the atmosphere. 

The surface temperature of the ocean, controlled by the mixing in the upper layers of the water, plays an important role in regulating the heat exchange between the atmosphere and ocean. Unfortunately, these exchange processes are not sufficiently known to determine quantitatively the role of the ocean in the global heat transport. Thus, further work remains to be done to clarify this point which is of great importance for climate research. 

Calvert, S.E., 1987. Oceanic controls on the accumulation of organic matter in marine sediments. In Brooks, J. and Fleet, A.J. (eds), Marine petroleum source rocks. Geol. Soc. Spec. Publ., 26, Blackwell, Oxford, pp. 137-151. 

The fundamental control on the chemical contribution of the ocean to climate is the rate of gas exchange across the air-sea interface. The flux, F, of a gas across this interface, into the ocean, is often written as... 

Burns, R.S. (1995) The Use of Artificial Networks for the Intelligent Optimal Control of Surface Ships, IEEE Journal of Oceanic Engineering, 20(1) Special Issue Advanced Control Signal Processing for Oceanic Applications, 20(1), pp. 66-72. 

Grimble, M.J., Patton, R.J. and Wise, D.A. (1979) The design of dynamic ship positioning control systems using extended Kalman filtering techniques, IEEE Conference, Oceans 79, CA, San Diego. 

Although the relationship of sediment adsorption to water concentration appears to be a controlling feature of shallow water systems such as lakes and coastal shelf water, the open ocean is more likely to contain soluble plutonium which seems to be unaffected by particulate matter. This is particularly evident in two oceanographic studies. Bowen et al have discovered a stratum of plutonium in the North Pacific at about 500m that has not changed depth appreciably from 1973 to 1980. How it arrived at this depth is subject to conjecture but it appears to be soluble plutonium which is not settling(17). Fukai et al have delineated plutonium maxima in the Mediterranean Sea which seem to be due to soluble species(18). Comparison of americium to plutonium ratios in this... 

The most important type of mixed solution is a buffer, a solution in which the pH resists change when small amounts of strong acids or bases are added. Buffers are used to calibrate pH meters, to culture bacteria, and to control the pH of solutions in which chemical reactions are taking place. They are also administered intravenously to hospital patients. Human blood plasma is buffered to pH = 7.4 the ocean is buffered to about pH = 8.4 by a complex buffering process that depends on the presence of hydrogen carbonates and silicates. A buffer consists of an aqueous solution of a weak acid and its conjugate base supplied as a salt, or a weak base and its conjugate acid supplied as a salt. Examples are a solution of acetic acid and sodium acetate and a solution of ammonia and ammonium chloride. 

Ear from being just the processing of water on Earth, this cycle is the basis for a wide range of meteorologic, geochemical, and biological systems. Water is the transport medium for all nutrients in the biosphere. Water vapor condensed into clouds is the chief control on planetary albedo. The cycling of water is also one of the major mechanisms for the transportation of sensible heat (e.g. in oceanic circulation) and latent heat that is released when water falls from the air. 

Rainwater and snowmelt water are primary factors determining the very nature of the terrestrial carbon cycle, with photosynthesis acting as the primary exchange mechanism from the atmosphere. Bicarbonate is the most prevalent ion in natural surface waters (rivers and lakes), which are extremely important in the carbon cycle, accoxmting for 90% of the carbon flux between the land surface and oceans (Holmen, Chapter 11). In addition, bicarbonate is a major component of soil water and a contributor to its natural acid-base balance. The carbonate equilibrium controls the pH of most natural waters, and high concentrations of bicarbonate provide a pH buffer in many systems. Other acid-base reactions (discussed in Chapter 16), particularly in the atmosphere, also influence pH (in both natural and polluted systems) but are generally less important than the carbonate system on a global basis. 

On the average, the air over roughly half of the Earth s surface has an upward velocity and half has a downward velocity. This frontal activity (Section 7.5.3) and the interactions of marine air with the cold ocean surface result in about half of the Earth being covered by clouds and half being clear. As will be discussed in Chapter 17, this large fractional cloud cover is extremely important to the Earth s climate because it controls the planetary albedo (reflectivity). 

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