Oxygen in ocean

Would you expect to find more dissolved oxygen in ocean water around the North Pole or in ocean water close to the equator Why ... 

The distribution of oxygen in ocean waters contains information about primary production. For example, the amount of excess oxygen present in the seasonal thermocline in the Pacific was long ago used to suggest that " C-based estimates of primary production were severely underestimating levels of primary production in the ocean (Shulenberger and Reid, 1981). Oxygen deficiencies in deeper waters have been used to estimate levels of export production (Jenkins, 1982). 

Eutrophication can be defined as the addition of nitrates and phosphates to the land through the use of fertilizers and soil conditioners. Eutrophication is a very common pollutant from fertilizers in farming or from natural causes. Eutrophication can deplete oxygen in ocean and freshwater lakes causing algae and phytoplankton blooms in the water. 

Oxygen is the most abundant element on earth The earths crust is rich in carbonate and sili cate rocks the oceans are almost entirely water and oxygen constitutes almost one fifth of the air we breathe Carbon ranks only fourteenth among the elements in natural abundance but trails only hydro gen and oxygen in its abundance in the human body It IS the chemical properties of carbon that make it uniquely suitable as the raw material forthe building blocks of life Let s find out more about those chemi cal properties... 

The solubility of oxygen in water with a salt content up to 1 mol L is only dependent on the temperature. The oxygen concentrations in equilibrium with air amount to (in mg L- ) 0°C, 14 10°C, 11 20°C, 9 and 30°C, 7. The depth of water has no effect in the case of ships. In Hamburg harbor in summer, 7.3 mg L are measured in depths up to 7 m. The value can be much lower in polluted harbors and even fall to zero [8]. In the open sea, constant values are found at depths of up to 20 m. With increasing depth, the Oj content in oceans with low flow rates decreases [12] but hardly changes at all with depth in the North Sea [13]. 

The overall reaction is exothermic but required the use of an electric arc furnace which, even with relatively cheap hydroelectricity, made the process very expensive. The severe activation energy barrier, though economically regrettable, is in fact essential to life since, in its absence, all the oxygen in the air would be rapidly consumed and the oceans would be a dilute solution of nitric acid and its salts. [Dilution of HN03(1) to HNOafaq) evolves a further 33.3kJmol at 25 C.l... 

Fig. 21.3 Vertical sections showing distribution of temperature, salinity, and oxygen in the Pacific Ocean, approximately along the meridian of I70°W. (After Sverdrup, H. U., Oceanography for Meteorologists, Allen and Unwin (1945))...

Straight-chain detergents don t work in hard water. Phosphates were added to detergents to soften the water, but phosphates are excellent fertilizer for algae in rivers and oceans. The algae blooms deplete the oxygen in the water, which in turn kills fish. Phosphates were replaced with other water softeners such as sodium carbonate and EDTA. 

Platt, T. and Harrison, W. G. (1985). Biogenic fluxes of carbon and oxygen in the ocean. Nature 318,55-58. 

To determine whether his Pacific samples were in fact representative of other oceans, Patterson and a Japanese colleague, Mitsunobu Tat-sumoto, began developing profiles of the lead in ocean layers in Atlantic and Mediterranean waters. Patterson hated ocean-going field trips he often became violently seasick, once so seriously that he had to be given oxygen. Because the ships were coated with leaded paints and compounds, sampling was tricky, too. Despite the problems, Patterson could see that, as in the Pacific, lead was concentrated in the upper portions of the Atlantic and Mediterranean. 

Methanogens, may be the Earth s oldest organisms, produce methane from carbon dioxide and hydrogen. They can survive only in an anaerobic (i.e., oxygen-free) environment and have been found in ocean trenches, in mud, in sewage, and in cow s stomachs. 

Fig. 20a. 6. Response curve of a Ru-fluorescence complex based oxygen optical sensor to oxygen in gas mixture. Courtesy of Ocean Optics, Inc.

Depth profiles of (a) salinity (%o), (b) dissolved oxygen (ml /L), and (c) percent saturation of dissolved oxygen in the Southeastern Atlantic Ocean (9°30 W 11°20 S). Samples were collected in March 1994. Dotted lines represent the curves generated by the one-dimensional advection-diffusion model (see text for details). The values of Dz, Vz, and J are the ones that best fit the data. Data are from Java Ocean Atlas (http /odf.ucsd.edu/joa). Values of percent saturation of oxygen less than 100 reflect the effects of aerobic respiration. Values greater than 100 indicate a net input, such as from photosynthesis. (See companion website for color version.)... 

Annual percent saturation of dissolved oxygen in (a) surface waters (Om) and (b) 50 m water depth. Source-. From Garcia, FI. E., et al. (2006). World Ocean Atlas 2005, Volume 3 Dissolved Oxygen, Apparent Oxygen Utilization, and Oxygen Saturation. NOAA Atlas NESDIS 63, U.S. Government Printing Office, p. 342. 

The following section will discnss the carbon, nitrogen, oxygen, and snlfur isotope composition of dissolved and particulate compounds in ocean and fresh waters. The isotopic compositions of dissolved components in waters of different origins depend... 

The present ocean is depleted in by at least 6%c relative to the total reservoir of oxygen in the crust and mantle. Muehlenbachs and Clayton (1976) presented a model in which the isotopic composition of ocean water is held constant by two different processes (1) low temperature weathering of oceanic crust which depletes... 

Rakestraw NM, Rudd DP, Dole M (1951) Isotopic composition of oxygen in air dissolved in Pacific Ocean water as a function of depth, J Am Chem Soc 73 2976... 

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