CHAPTER 2: PERSPECTIVE 



It is important that each pollution incident be viewed in the 

 context of the environment in which it occurred. Only then can the 

 significance of pollution incidents and the importance of studies be 

 recognized. This chapter provides some environmental considerations 

 which attempt to place the Tsesis incident into perspective. 



The Tsesis spill obviously has implications for the Baltic, where 

 the spill took place; in addition, a discussion is provided which com- 

 pares the situation with environmental conditions in Alaska, the focus 

 of which was the underlying justification for U.S. support. 



2.1 Baltic Perspective 



(Ragnar Elmgren, Lars Westin, Olle Linden) 



During the last decade a number of valid studies on various effects 

 of oil spills in marine environments have been carried out. These 

 studies have dealt with extremely large and spectacular spills as well 

 as spills of a more normal size. In few instances, however, have more 

 than a few aspects of a spill been studied, and often the concern has 

 been with littoral systems or bird populations. Few studies have at- 

 tempted to illustrate the total effect of an oil spill on all the var- 

 ious parts of the ecosystem (COMS, 1978; Kuhnhold, 1978). The Tsesis 

 study was an attempt to do so and also represents one of the few studies 

 carried out in the Baltic or in brackish waters in general. 



The Baltic Sea is one of the largest areas of brackish water in the 



2 

 world, with a surface area of 366,000 km . It is the largest extensive 



area of low but stable salinity, mostly within the p-mesohaline range 



(5-10 °/oo S = 0.5 - 1% salinity). The fluctuations of the surface 



salinity are small in spite of occasional powerful injections of North 



Sea water, which greatly affect the salinity of the deeper Baltic waters 



A salinity gradient exists from north to south, from 2-3 /oo S, in the 



innermost Bothnian Bay, to about 15-20 /oo S in Kiel Bay. Tides are 



almost entirely absent. 



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