Rivers are warming and losing oxygen faster than oceans. Of nearly 800 rivers studied, warming occurred in 87% and oxygen loss occurred in 70%. Within the next 70 years, river systems, especially in the American South, are likely to experience periods with such low levels of oxygen that the rivers could “induce acute death” for certain species of fish and threaten aquatic diversity at large. Declining oxygen in rivers, or deoxygenation, also drives the emission of greenhouse gases and leads to release of toxic metals. Most Americans reside within a mile of a river or stream. I’m guessing that if studies of lakes are done, they will find the same thing.
www.psu.edu/news/research/story/rivers-rapidly-warming-losing-oxygen-aquatic-life-may-be-risk-study-finds/