Anti-estuarine

The concentration of dissolved nutrients in the deep waters of the Eastern Mediterranean is much lower than those in other oceans of the world, and when these are mixed into the surface waters they support very low primary productivity. The basic reason for this ultra-oligotrophic status is that the Mediterranean has an anti-estuarine (reverse thermohaline) circulation in which nutrient-depleted surface waters flow into the western basin at the Straits of Gibraltar and then on into the eastern basin at the Straits of Sicily. The deeper counter current consists of Levantine Intermediate Water (LIW) which contains a significant amount of dissolved nutrients. 

The Mediterranean is situated at the northern boundary of the desert climatic belt. As a result there is a significant net loss of water from the basin. The Mediterranean in general, and the Eastern Mediterranean in particular, has a large excess of evaporation over precipitation. This results in an anti-estuarine (reverse thermohaline) circulation. Low salinity water flows into the Mediterranean basin from the eastern North Atlantic. This water flows in within the upper water layers at the Straits of Gibraltar. The salinity of this surface water is 36.15. The surface water moves to the west generally following the coast of North Africa. It then flows through the Straits of Sicily. However, the flow of... 

The Straits of Sicily represent a physical barrier which lies at the entrance to the Eastern Mediterranean. It is approximately 500 m deep and represents a significant control on the biogeochemical processes occurring within the eastern basin. There also is an anti-estuarine circulation through these straits because evaporation exceeds precipitation in the eastern basin. A surface and subsurface flow of modified Atlantic waters, low in nutrients, flows eastwards into the eastern basin while LIW with relatively higher nutrients flows westwards out of the basin. This is the fundamental feature that causes the Eastern Mediterranean as a whole to be oligotrophic. 

Martin JM, Nijampurkar V, Salvation F (1978b) Uranium anti Thorium isotope behavior in estuarine systems. In Biogeochemistry of estuarine sediments. UNESCO, p 111-127 Mathieu D, Bemat M, Nahon D (1995) Short-lived U and Th isotope distribution in a tropical laterite derived from Granite (Pitinga river basin, Amazoitia, Brazil) application to assessment of weathering rate. Earth Planet Sci Lett 136 703-714... 

Anti-fouling tests were carried out on brush coated plastic laminate panels which had been given a primary coating of anti-corrosion paint. Performance was measured by visual observations of the panels after prolonged immersion (4 - 12 months) in a known high-fouling estuarine environment. 

Tin Weak evidence for ultratrace essentiality in rats Organotin compounds used as bacteriostatsand fungistats its use in anti-foulant boat paints now discouraged because of danger to estuarine and marine life. ... 

Butyltins are mainly investigated in bivalve or mollusc tissues, e.g. oysters, because of the anthropogenic contamination of water with anti-fouling paints. Harbour or estuarine areas are of main concern, as the major contamination stems from boat hull painting, and estuaries are common grounds for oyster or shellfish farming. 

TBT, being an organotin compound, is of particular importance for sediment samples, as this species is the main component in anti-fouling paints for boats, and thus can be found in substantial amounts in harbour and estuarine sediments. Organotin compounds also accumulate in mussels, and organotin speciation can be carried out using similar methods for both types of samples. ... 

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