Arctic areas Ocean

The Antarctic area at the extreme South and the Arctic area at the extreme North complete the classical zonation of the oceans (George 1979). I have added a fiirther commodious zonation, the Internal Seas. 

Saltwater fish Maintaining the proper saline (salt) concentration is important to the health of saltwater fish. In the ocean, the presence of salt in arctic areas keeps the water from freezing, allowing aquatic life to be sustained. 

Freezing estuaries can be found all around the Arctic Ocean and also in sub-arctic areas in the Atlantic and the Pacific Oceans. The ice conditions in estuaries can be quite dramatic with rapid freezing and melting. During out-flow events, cold and brackish siuface water may form a thin layer which may accelerate the freezing. On the other hand, during stormy inflow events with warm ocean water, even a thick ice-cover may melt fast. For a review of ice covered estuaries see Omstedt (1997). 

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. 

Over the past decade, plastic debris has become a common feature of beaches and coastal waters adjoining populated areas of Europe (36-38), the Mediterranean (39-41), North and Central America (42-44) and New Zealand (45). Plastics are also present in the open ocean both near the major shipping lanes and in the most remote regions of the world (the Arctic (46), the Benguela Current (47), the Cape Basin area of the South Atlantic (48), the Humboldt Current in the South Pacific (49), and the Antarctic (50, 51). 

PFCs have been detected in environmental and biological samples being widespread around the world including water, soils and sediments, human samples, and even in remote areas such as the Arctic (atmosphere [34], Arctic Ocean [35], biological samples [36, 37] and few reviews have been published [38, 39]) or Antarctic (biological samples as penguins or seals [40, 41]). 

Despite the restrictions to usage and production there still remain extensive amounts of DDT and its metabolites in the environment. Traces of DDT were detected all around the world, including regions where there are no direct sources, such as open ocean waters [Tanabe and Tatsukawa (1983),Iwata et al (1993)], the Arctic [Patton et al (1989)], and high mountain areas [Villa et al (2003)]. 

Temperatures low enough to prevent any form of life do not occur on Earth. The coldest areas, the Antarctic and Arctic, were considered in Chapters 7.12 and 7.11. High pressures in the oceans also do not prevent wide forms of life, rich of unusual secondary metabolites (Chapter 9). 

Concentrations of PFAs have been determined in a range of biota from the North American Great Lakes (Tables 12-16 and Fig. 9). Concentrations of PFAs in the biota of the Great Lakes were similar to those from other urbanized and industrialized areas of North America and Europe [16,94,98-100]. However, they are less than those in wildlife in more remote locations such as the open ocean or Arctic and Antarctic [ 17,88,89,95,101 ]. 

The entire area of the Arctic Ocean is only 3.8% of the world s total ocean surface, but its role in C02 absorption varies from 23% to 38% (16.7GtCyr l-... 

PCNs have recently been reported in ambient air from Europe, North America and the Arctic [204, 210,237, 238]. The concentrations are generally higher in urbanized areas compared to remote areas. The average PCN concentration in Chicago air (winter 1995) was reported to be 68 pg m 3 compared to 12 pg m 3 in air from the East Arctic Ocean (summer 1996) [210, 238]. The PCN concentrations in e. g., Chicago air are approximately one order of magnitude lower than typical PCB values for urban centers [210]. The main part of the CNs in ambient air from background locations is found in the gas phase (98%) and only small amounts on the particles (2%) [237]. Mainly tri- to pentaCNs are found in the gas phase and predominantly hexa- to octaCN in the particle phase [210]. 

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