Estuarine processes

Methylgermanium species also behave conservatively in estuaries. As with the oceans, concentrations vary directly with salinity, concentrations being very low in freshwaters, whether or not the river is polluted. Again, it appears that estuarine processes do not methylate or demethylate germanium species9. 

Fig. 11. Estuarine processes affecting organic matter input to the oceans.

McHugh, 3.L., 1976. Estuarine fisheries are they doomed In M. Wiley (ed.) Estuarine Processes. Academic Press, New York, Vol. 1, pp. 15-27. 

Schubel, J.R., and Hirschberg, D.J. (1978) Estuarine graveyard and climatic change. In Estuarine Processes (Wiley, M., ed.), pp. 285-303, Academic Press, New York. 

Martin, J. M., and V. V. Gordeev. 1986. "River input to ocean system a reassessment." In Estuarine processes Application to the Tagus estuary, eds. Unesco and CAN, pp. 203-240. 

Hedges, J. I., and Keil, R. G. (1999). Organic geochemical perspectives on estuarine processes Sorption reactions and consequences. Mar. Chem. 65, 55-65. 

Haines, E., Chalmers, A., Hanson, R., and Sherr, B. (1977). Nitrogen pools and fluxes in a Georgia salt marsh. In Estuarine Processes, Vol. 11. Circulation, Sediments, and Transfer of Material in the Estuary. Academic Press, Inc., New York. pp. 241—254. 

The purpose of this study was to obtain information regarding the speciation of cadmium (Cd), lead (Pb), and copper (Cu) in an estuary area. Only the distribution of metal in the soluble fraction (size smaller than 0.45 pm) will be investigated in this paper. The Seine estuary was chosen in order to study the effects of estuarine processes on the behaviour of metals and organic-matter carried by rivers discharging into very high tides (such tides produce considerable water displacement). 

The specific dissipation due to wave power is strongly dependent on water depth and, therefore, will have sharply defined bounds in most estuaries. It Is determined by the depth, the available fetch, and the intensity of the winds having sufficient duration to raise a fully developed sea. For Long Island Sound the wave-dominated zone is that in water shallower than 18 m this constitutes 54% of the total area of the Sound. Within the wave-dominated zone the particle motion due to waves at the water surface is more effective in exciting sediment from the bottom than other causes of water movement. Large quantities of sediment may be set in motion by the waves and relatively small currents can then effect substantial transport of the material so excited. An example of an estuary in which wave-excited sediment is an important fraction of the total sediment available for estuarine processes is the Tay, where wave erosion followed by overland flow on bare mudflats exposed on the ebb of the tide results in large sediment concentrations in the water of the estuary (Buller et al., 1975). 

The further development of mathematical representations of estuarine processes should proceed simultaneously with investigations of both specific sedimentary processes and regional sedimentary systems. For the model proposed here some of the specific processes that deserve attention in the future include the processes that control the rate of formation of marine mud at the base of the surficial layer of agglomerates and the relationship between the eddy-diffusion coefficient for sand transport and fluctuations in the water velocity. The study of specific processes tell us little about the long-term manifestations of these processes. For this there is the need to develop comprehensive descriptions of estuarine sedimentary systems and to begin to contrast and compare sediment budgets in different coastal areas. 

Atema, J., 1976. Sublethal effects of petroleum fractions on the behavior of the lobster, Homarus americanus, and the mud snail, Nassarius obsoletus. In M. Wiley (Editor), Estuarine Processes, 1. Uses, Stresses and Adaptation to the Estuary. Academic Press, London, pp. 302—312. 

Morris, J. T. 2000. Effects of sea-level anomalies on estuarine processes. In J. E. Hobbie (ed.) Estuarine Science A Synthetic Approach to Research and Practice, pp. 107-127. 

The broad range of scales of variability of estuarine processes requires that quality controls also include data types complementaiy to fixed in situ sensors. Of particular interest are data collected from on-board sensors during vessel surveys, and an increasing range of remote sensing techniques. 

In order to appreciate and understand the ocean chemistry of the lanthanides, one must be aware of the central role of rivers and estuaries in shaping the input of lanthanides to the sea. Rivers are the major source of lanthanides to the oceans, and modification of lanthanide fluxes to the ocean via riverine and estuarine processes will constitute an important aspect of this review. 

---