8.6 Abiotic Processes of Decomposition of Some Organic Contaminants 339 



8.6.1 Solar Oxidation of Benzo(a)pyrene 341 



8.6.2 Influence of Ultraviolet Radiation on the Fate of PCBs 343 



Chapter 8 References 347 



Chapter 9: ECOTOXICOLOGY 353 



9.1 Effects of Pollutants on Plankton Communities 355 



9. 1 . 1 Investigation of Negative Effects and Critical Concentrations of Some Toxic 

 Substances on the Plankton Community 357 



9. 1 .2 Effects of Hexachlorocyclohexane on Nitrogen Cycling in Natural Plankton 

 Communities 364 



9.2 Toxicity of Sediments to Test Organisms 371 



9.2.1 Acute Toxicity Testing of Sediments 369 



Chapter 9 References 377 



Chapter 10: MARINE BIRDS 379 



10.1 Water Masses and Seabird Distributions in the Southern Chukchi Sea 381 



10.2 Associations Between Seabirds and Water Masses in the Northern Bering Sea 388 



Chapter 10 References 397 



Summary 399 



General Conclusions 405 



Appendix A 407 



