Tidal range

Figure 5.9. Comparison of the technical electricity generation potential with the realisable mid-term potential for tidal and wave energy in Europe. For the estimate of the technical tide potential, exploitable sites with a mean tidal range above 3 m are included.

Tidal barriers utilise the rise and fall of the tide (the tidal range) to trap seawater at high tide in a reservoir behind a barrage. As the water leaves or enters the reservoir in a constrained duct, submerged hydroturbines generate electricity, as in conventional hydropower. There is only one significant tidal barrier power plant, which is at La Ranee, Brittany, in France. 

Kim, S.K., Lee, D.S., Oh, J.R., Kahng, S.H., 2000a. Effects of extreme tidal range on characteristics of polychlorinated biphenyl distribution in sediment of industrial Incheon North Harbor, Korea. Environ. Toxicol. Chem. 19, 2448-2456. 

If the DMS inventory in Salt Pond is at steady state in summer (5), production should approximately balance removal. Tidal removal of DMS to Vineyard Sound is minimal. Outflow from Salt Pond is thought to be primarily surface water, and using a maximum tidal range of 0-0.2 m/d and a mean surface water concentration of 10 nmol/L, we calculate an export rate of less than 2 /imol/m2/d. The water-air flux of DMS may be calculated using the two film model of liss and Slater (22 flux = -ki C, ). With the same surface water DMS concentration (C ) and an estimated mass transfer coefficient (ki) for DMS of 1.5 cm/h, the projected flux of DMS from the pond into the atmosphere would be 4 /unol/m2/d. This compares with the range of estimated emissions from the ocean of 5-12 /imol/m2/d (1). 

Macrotidal coastal and oceanic systems with a high mean tidal range greater than 4 m. 

Mesotidal coastal and oceanic systems with an average tidal range of 2 to 4 m. 

Table 3 Mean and maximal tidal ranges in the Black Sea, cm [3]...

The differences between these reefs probably reflect differences in their structural framework and variations in wave characteristics and tidal range in the two environments. Anaerobic reactions in reef interstitial waters may not progress far if reef structures are open and well flushed. If, however, the systems are nearly closed, little fresh reactant will enter via seawater exchange and mass transfer will be limited by the reactants trapped in the reef interstitial waters. An important conclusion of Sansone s studies was that thermodynamic disequilibrium among dissolved species such as CH4 and S04 implies microzonation of chemical reactions. Microzonation resulting in slight differences in reef interstitial water compositions may account for the coexistence of different cement mineralogies in reef structures. 

Tidal power can use either conventional or new technology to extract energy from the tides. It is usually best deployed in areas where there is a high tidal range, which includes many areas of the United Kingdom as well as the United States, New Zealand, and parts of the west coast of India. 

Thong, K.L., Sasekumar, A. and Marshall, N. (1993) Nitrogen concentrations in a mangrove creek with a large tidal range, Peninsular Malaysia. Hydrobiologia, 254, 125-132. 

Under exceptional circumstances, when the FBI has a very narrow vertical range and/or tidal amplitude is very small, it is possible to estimate the elevation of a former mean sea-level to +0.08 m (Antonioli et al. 1999), or +0.25 m (Lambeck 2002). However in most instances, FBIs occupy a comparatively wide interval within the intertidal zone and/or a large tidal range expands the vertical interval over which an FBI can survive. This commonly increases the uncertainty in relating a fossil FBI with a palaeo sea-level to a metre or more, usually sufficient to obscure any fine structure that might be present in a regional sea-level curve. 

Fig. 7. Ranges of elevation in which different plant species occur on a salt marsh near Guilford, Connecticut. Datum is mean sea level (MSL). The tidal ranges shown are the highest astronomical tide (HAT), mean high-water springs (MHWS), and mean high-water neaps (MHWN).

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