Other Enclosed Seas

It is particularly instructive to compare the Baltic Sea with the Mediterranean Sea. The two inland seas of course differ with respect to size (area and depth) and climate, but of more principal interest are the differences in exchange with the open 

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Local conditions may modify this profoundly in special areas. In the Arctic and Antarctic, and where there is dilution by large rivers, the salinity may be considerably less, and it may vary greatly according to season. Salinity is well below normal in the Baltic, and may fall nearly to zero at the head of the Gulf of Bothnia. In enclosed seas like the Mediterranean, Black Sea and Red Sea, on the other hand, where there is rapid evaporation, salinity may reach 40 parts per thousand. The total salt content of the inland Dead Sea is 260 g/kg compared to 37 g/kg for the Atlantic Ocean. 

According to Perillo (1995, p. 4), an estuary is defined as a semi-enclosed coastal body of water that extends to the effective limit of tidal influence, within which sea water entering from one or more free connections with the open sea, or any other saline coastal body of water, is significantly diluted with fresh water derived from land drainage, and can sustain euryhaline biological species from either part or the whole of their life cycle. ... 

Corals animals of the Cnidaria phylum (formerly Coe-lenterata), with a calcareous skeleton. Sea anemones and jellyfishes are Cnidaria without skeletons Dentine also called ivory, the inner hard tissue of the tooth. The bulk of a tooth is made up of dentine Enamel the outer layer covering the tooth Frustule the siliceous shell or exoskeleton of a diatom. It is composed of two valves (epitheca and hypotheca), one overlapping the other, like a pill box and its cover Mollusks invertebrates having a soft unsegmented body usually enclosed in a shell. Mollusca mainly includes Bivalvia, Gastropoda, and Cephalopoda... 

Other sources of pollution include the use of organomercury-containing fungicides in wood pulp for paper-making. Effluent from such processing plants has contaminated rivers. Predatory fish (for the same reason as predatory birds) also tend to contain relatively higher levels of mercury than non-predatory fish, especially those from enclosed, relatively non-tidal areas like the Mediterranean Sea. 

Diffusion of Tc and other fission products such as Cs and -Eu as well as the actinides Np, Am and natural uranium was studied in a sample of a sediment from an enclosed brackish water bay of the Baltic Sea. Under oxidizing conditions TcOq did not interact with the sediment to any large degree. Deeper laying sediments were depleted of oxygen and showed negative redox potentials. In this case the apparent diffusivity of Tc 0 =5-10 m -s was low compared to compacted clay with >a=8 -10 " m- s", indicating a reduction of TcOq [30]. 

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