Chapter 1 The Hypoxic Environment

摘要: Low dissolved oxygen environments occur in a wide range of aquatic systems, and vary temporal frequency, seasonality, persistence. While there have always been naturally occurring low habitats, anthropogenic activities related primarily to organic nutrient enrichment led increases hypoxia anoxia both freshwater marine systems. Lakes coastal areas with seasonal stratification tend be highly sensitive the consequences enrichment. Many systems that are currently hypoxic were not reported concentrations when first studied. The rapid rise number lagged about 20 years behind increased use industrial fertilizer. future status its for fishes will depend on combination climate change (primarily from warming, altered patterns wind, currents, precipitation) land expanded agriculture loadings). If next 50 humans continue modify degrade as previous years, human population pressure likely main driving factor spreading dead zones factors secondary. Climate forcing, however, make more susceptible development through direct effects stratification, solubility oxygen, metabolism, mineralization rates, particularly lakes semienclosed areas.