Transport and oceans

Borole DV, Krishnaswami S, Somayulu BLK (1982) Uranium isotopes in rivers, estuaries and adjacent coastal sediments of western India Their weathering, transport and oceanic budget. Geochim Cosmochim Acta 46 125-137... 

Equations (4.1) through (4.18) are supplemented in each cell of the spatial division of the ocean surface with initial conditions (Table 4.3). The boundary conditions for Equations (4.11) through (4.18) are zero. The calculation procedure to estimate sulfur concentration consists of two stages. First, at each time moment th for all cells Qiy, Equations (4.1)-(4.18) are solved by the quasi-linearization method, and all reservoirs of sulfur are estimated for ti+x = tf + At, where time step At is chosen from the convergence state of the calculation procedure. Then, at moment t(+1 using the climate unit of the global model these estimates are specified with account of the atmospheric transport and ocean currents over time At. 

MultiwaU. shipping sacks are suitable for transport in aU kinds of carriers from tmcks to seafaring vessels. Particular care must be taken to prevent the storage of objects with sharp projections adjacent to the bags in case of doubt, it is advisable to line the enclosure with kraft paper of a basis weight >23 kg. Additional rules for the transportation of multiwaU sacks are contained in appHcable tariff specifications and should be consulted for rail, tmck, and ocean-going shipments. 

Water Transport Barges, scows, and special boats have been used in the past to transport sohd wastes to processing locations and to seaside and ocean disposal sites, but ocean disposal is no longer practiced by the United States. Although some self-propelled vessels (such as U.S. Navy garbage scows and other special boats) have been used, most common practice is to use vessels towed by tugs or other special boats. 

Owing to the stability of the uranyl carbonate complex, uranium is universally present in seawater at an average concentration of ca. 3.2/rgL with a daughter/parent activity ratio U) of 1.14. " In particulate matter and bottom sediments that are roughly 1 x 10 " years old, the ratio should approach unity (secular equilibrium). The principal source of dissolved uranium to the ocean is from physicochemical weathering on the continents and subsequent transport by rivers. Potentially significant oceanic U sinks include anoxic basins, organic rich sediments, phosphorites and oceanic basalts, metalliferous sediments, carbonate sediments, and saltwater marshes. " ... 

FIGURE 18-15 Because fossil fuel reserves are limited, they must be extracted from wherever they are found. This platform is used to extract petroleum from beneath the ocean. The natural gas accompanying it cannot easily be transported, and so it is burned off. 

In gridpoint models, transport processes such as speed and direction of wind and ocean currents, and turbulent diffusivities (see Section 4.8.1) normally have to be prescribed. Information on these physical quantities may come from observations or from other (dynamic) models, which calculate the flow patterns from basic hydrodynamic equations. Tracer transport models, in which the transport processes are prescribed in this way, are often referred to as off-line models. An on-line model, on the other hand, is one where the tracers have been incorporated directly into a d3mamic model such that the tracer concentrations and the motions are calculated simultaneously. A major advantage of an on-line model is that feedbacks of the tracer on the energy balance can be described... 

Transport in water is an important mechanism for transfer of biogeochemical elements between the atmosphere, land, and oceans. In particular, rain is the primary means of removal from the atmosphere for many substances, and rivers (and to some extent groundwater) convey weathering products and runoff from the land surface to the oceans. 

Unlike other biogeochemical elements, phosphorus does not have a significant atmospheric reservoir. Thus, while some amount of phosphorus is occasionally dissolved in rain, this does not represent an important link in the phosphorus cycle. River runoff is the primary means of transport between the land surface and oceans, and unlike the other elements discussed. 

Zauker, F. and Broecker, W. S. (1992). Influence of interocean fresh water transports on ocean thermohaline circulation. /. Geophys. Res. 97, 2765-2773. 

The subsequent fate of the assimilated carbon depends on which biomass constituent the atom enters. Leaves, twigs, and the like enter litterfall, and decompose and recycle the carbon to the atmosphere within a few years, whereas carbon in stemwood has a turnover time counted in decades. In a steady-state ecosystem the net primary production is balanced by the total heterotrophic respiration plus other outputs. Non-respiratory outputs to be considered are fires and transport of organic material to the oceans. Fires mobilize about 5 Pg C/yr (Baes et ai, 1976 Crutzen and Andreae, 1990), most of which is converted to CO2. Since bacterial het-erotrophs are unable to oxidize elemental carbon, the production rate of pyroligneous graphite, a product of incomplete combustion (like forest fires), is an interesting quantity to assess. The inability of the biota to degrade elemental carbon puts carbon into a reservoir that is effectively isolated from the atmosphere and oceans. Seiler and Crutzen (1980) estimate the production rate of graphite to be 1 Pg C/yr. 

Recent revisions to the boundary conditions (ice-sheet topography and sea surface temperatures) have added uncertainty to many of the GCM calculations of the past two decades. Moreover, all of these calculations use prescriptions for at least one central component of the climate system, generally oceanic heat transport and/or sea surface temperatures. This limits the predictive benefit of the models. Nonetheless, these models are the only appropriate way to integrate physical models of diverse aspects of the Earth systems into a unified climate prediction tool. 

It has been recognized for some time that fluids in motion, such as the atmosphere or the ocean, disperse added materials. This properly has been exploited by engineers in a variety of ways, such as the use of smoke stacks for boiler furnaces and ocean ontfalls for the release of treated wastewaters. It is now known that dilution is seldom the solution to an enviromnental problem the dispersed pollutants may accumulate to undesirable levels in certain niches in an ecosystem, be transformed by biological and photochemical processes to other pollntants, or have nnanticipated health or ecological effects even at highly dilute concentrations. It is therefore necessary to rmderstand the transport and transformation of chemicals in the natural environment and through the trophic chain ctrlminating in man. 

Th AS A TRACER FOR PARTICLE TRANSPORT AND SEDIMENT PROCESSES IN THE COASTAL OCEAN... 

The short4ived particle reactive radionuclides of the U/Th series also have enormous potential for tracking particle source and transport in ocean margins. Mass balances comparing inventories in sediments with supply can be used to determine import or export of particles to an area. Such approaches are increasingly important in understanding the fates of particle-reactive contaminants whose sources are often enhanced in the coastal ocean. Studies of especially when supplemented by other... 

Water vapor enriched in oxygen-16 is transported by wind in the atmosphere from the sea to land. When the water vapor condenses and precipitates as rain, snow, or hail, the water becomes rich in oxygen-16. Eventually the oxygen-16 rich water is incorporated into rivers, lakes, glaciers, and polar ice, which are, therefore, also rich in oxygen-16. Thus the isotopic composition of groundwater and the water of rivers, lakes, and glaciers is not the same as in seas and oceans. 

The Water Cycle. The evaporation of water from land and water surfaces, the transpiration from plants, and the condensation and subsequent precipitation of rain cause a cycle of transportation and redistribution of water, a continuous circulation process known as the hydrologic cycle or water cycle (see Fig. 86). The sun evaporates fresh water from the seas and oceans, leaving impurities and dissolved solids behind when the water vapor cools down, it condenses to form clouds of small droplets that are carried across the surface of the earth as the clouds are moved inland by the wind and are further cooled, larger droplets are formed, and eventually the droplets fall as rain or snow. Some of the rainwater runs into natural underground water reservoirs, but most flows, in streams and rivers, back to the seas and oceans, evaporating as it travels. 

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