Oceans surface waters

One form of solar heat does offer interesting possibilities and is refeiTcd to as OTEC (Ocean-Thermal Energy Conversion). The OTEC power plant principle uses the solar heat of ocean surface water to vaporize ammonia as a working fluid in a Rankine cycle. After the fluid is expanded in the turbine, it is condensed by the 22°C colder... 

The turnover time of carbon in biota in the ocean surface water is 3 x 10 /(4 + 36) x lO yr 1 month. The turnover time with respect to settling of detritus to deeper layers is considerably longer 9 months. Faster removal processes in this case must determine the turnover time respiration and decomposition. 

An important example of non-linearity in a biogeochemical cycle is the exchange of carbon dioxide between the ocean surface water and the atmosphere and between the atmosphere and the terrestrial system. To illustrate some effects of these non-linearities, let us consider the simplified model of the carbon cycle shown in Fig. 4-12. Ms represents the sum of all forms of dissolved carbon (CO2, H2CO3, HCOi" and... 

Many hydrologic reservoirs can be further subdivided into smaller reservoirs, each with a characteristic turnover time. For example, water resides in the Pacific Ocean longer than in the Atlantic, and the oceans surface waters cycle much more quickly than the deep ocean. Similarly, groundwater near the surface is much more active than deep reservoirs, which may cycle over thousands or millions of years, and water frozen in the soil as permafrost. Typical range in turnover times for hydrospheric reservoirs on a hillslope scale (10-10 m) are shown in Table 6-4 (estimates from Falkenmark and Chapman, 1989). Depths are estimated as typical volume averaged over the watershed area. 

Over 20% of the world s open ocean surface waters are replete in light and major nutrients (nitrate, phosphate, and silicate), yet chlorophyll and productivity values remain low. These so-called "high-nitrate low-chlorophyll" or HNLC regimes (Chisholm and Morel, 1991) include the sub-arctic North Pacific (Martin and Fitzwater, 1988 Martin et al, 1989 Miller et al, 1991), the equatorial Pacific (Murray et al, 1994 Fitzwater et al, 1996) and the southern Ocean (Martin et al.,... 

Oceanic surface waters are efficiently stripped of nutrients by phytoplankton. If phytoplankton biomass was not reconverted into simple dissolved nutrients, the entire marine water column would be depleted in nutrients and growth would stop. But as we saw from the carbon balance presented earlier, more than 90% of the primary productivity is released back to the water column as a reverse RKR equation. This reverse reaction is called remineralization and is due to respiration. An important point is that while production via photosynthesis can only occur in surface waters, the remineralization by heterotrophic organisms can occur over the entire water column and in the underlying sediments. 

Oceanic circulation. The process of ocean circulation described earlier yields an ocean circulation pattern that results in progressively older deep water as the water passes, in sequence from the Atlantic, Indian, to the Pacific Ocean. Surface water returns relatively quickly to the place of origin for the deep water. 

Emerson, S., Quay, P., Karl, D. et al. (1997). Experimental determination of the organic carbon flux from open-ocean surface waters. Nature 389, 951-954. 

Oceanic surface water is everywhere supersaturated with respect to the two solid calcium carbonate species calcite and aragonite. Nevertheless carbonate precipitation is exclusively controlled by biological processes, specifically... 

Fig. 11-24 Carbon-14 in the troposphere and the ocean surface water 1962-1981. values for ocean surface water during this period range from 0-15% with no trend over time. (Modified with permission from R. Nydal and K. Lovseth (1983). Tracing bomb in the atmosphere. /. Geophys. Res. 88, 3621-3642, American Geophysical Union.)...

PFOA observations To evaluate MPI-MCTM model results observational data of PFOA from ship cruises in the Atlantic, Indian and Pacific Oceans were taken from literature (summarised in Yamashita et al (2008)). The data was collected between 2002 and 2006 in a global ocean monitoring initiative. Samples were taken from ocean surface water. Vertical profiles were sampled in the Labrador sea, the Mid Atlantic ocean, the South Pacific ocean and the Japanese sea, where water probes were done at several depths down to 5500 m. The limit of quantification for PFOA was determined as 6 pg/L. 

The oceanic distribution of cobalt is similar to that of manganese, although cobalt concentrations are 10-100 times smaller maximum concentrations are 100-300 pM in surface waters, decreasing to 10 pM at depths below 1000 m. As concentrations of cobalt in seawater are so low, it may become biolimiting in open ocean surface waters. 

Tsunogai and Nozaki [6] analysed Pacific Oceans surface water by consecutive coprecipitations of polonium with calcium carbonate and bismuth oxychloride after addition of lead and bismuth carriers to acidified seawater samples. After concentration, polonium was spontaneously deposited onto silver planchets. Quantitative recoveries of polonium were assumed at the extraction steps and plating step. Shannon et al. [7], who analysed surface water from the Atlantic Ocean near the tip of South Africa, extracted polonium from acidified samples as the ammonium pyrrolidine dithiocarbamate complex into methyl isobutyl ketone. They also autoplated polonium onto silver counting disks. An average efficiency of 92% was assigned to their procedure after calibration with 210Po-210Pb tracer experiments. 

The 6180 in Byrd core melted ice as a function of depth has been measured by mass spectrometry [4,5]. Since the 6180 scale depends on the temperature of the ocean water that developed into snow flakes [6], accurate dating of the core itself is necessary to reveal the temperature history of the ocean surface water. Oeschger et al., [7] measured the 14C contents of C02 extracted from 3 tons of ice melted i n situ, at depths of 100, 175, 270, and 380 m near the Byrd site, their 14C ages for 270- and 380-m depths are 1300 700 and 3000 500 years, respectively. 

Despite the intriguing results suggesting a kinetically limiting surface adsorption of Fe in oceanic surface waters [192], few other experiments have been performed that specifically examine the kinetics of the metal adsorption process. Among other complications, kinetic control of the transport would be expected to cause undersaturation of the carriers that could could produce a gradient of variable [metal]/[ligand] that would affect the overall flux. This would appear to be an area that is ripe for future research. 

One with concentrations of metals corresponding to open-ocean surface water with an information value for total iron concentration. 

Nutrient calibration solutions in seawater are commonly prepared by dissolving known amounts of pre-dried, solid, primary standard salts in low-nutrient seawater. Low-nutrient seawater must be collected from oligotrophic open-ocean surface water to minimize background nutrient... 

The relationship between the rate constant for ligand-metal binding kf) and the concentration of free metal ion [M"+] in oceanic surface waters for the biologically essential trace metals. Data plotted from Table 1 in Hudson, J. M and F. M. M. Morel (1993). Deep Sea Research, 40, 129-150. 

Incident solar energy is absorbed by the surface water of the oceans. Ocean surface temperatures in excess of 26°C occur near the equator. Pure water has a maximum density at a temperature of 4°C. The chilled water tends to settle to the depths of the ocean. The combination of the warmed ocean surface water and cold deep ocean water provides the thermodynamic condition needed to operate a heat engine called ocean thermal energy conversion (OTEC). A typical closed-cycle OTEC Rankine cycle using a working fluid such as ammonia or a freon is suggested. 

The ocean surface water is warm (27° C at equator) and deep ocean water is cold (5°C at 2000 m depth). If a vapor cycle operates between these two thermal reservoirs, is water or refrigerant a better choice as the working fluid for this power plant ... 

Heat source fluid = warm ocean surface water, ri=26°C, Pi = 101kPa, T2 = 22°C, and p2=101kPa Heat sink fluid = cold deep ocean water, T3 = 5°C, p3 = 101kPa, T4 = 9°C, and p4=101kPa... 

Heat source fluid = warm ocean surface water, ri=26°C, i = 101kPa, T2 = 20°C, and 2=101kPa... 

Sea level rise. With increasing surface temperatures the average sea level will rise because of three factors melting of polar ice caps, receding of glaciers, and thermal expansion of the ocean surface waters. Combining all three factors,... 

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