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Most sites experienced episodic hypoxia , which is a precursor to development of seasonal hypoxia . ( 20 ) The large number of sites partially reflects the fact that the Baltic Sea is one of the most data rich regions of the world with no tidal mixing and complex bottom topography creating conditions favorable for hypoxia , although these are only the " monitored areas " and many more hypoxic sites probably exist in the Baltic Sea coastal zone .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Anatomy 
Text: {0} 
Answer:
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