Heat waves, storms and floods affect the thermal regime and biogeochemical functioning of lakes and rivers . Extreme heat waves lead to abnormally high water temperatures  and reduce the mixing of lakes , causing a decrease in oxygen and deep-water oxygen renewal . Ectotherms such as fish and invertebrates are particularly susceptible to such temperature and oxygen stress . Their metabolic demands increase with rising temperature and a suitable habitat is eroded due to both high temperatures and lower oxygen concentrations in lakes and rivers. Till et al.  attributed 502 fish kill events in the Wisconsin lakes  to warmer summers in lakes that experienced abnormally high water temperatures. Such events are predicted to double by 2041-2059 and increase four-fold by 2081-2099 compared to historical levels . This anticipated increase in die-offs may facilitate warm-water fish species displacing cool-water species . Floods mobilise nutrients and sediment, and aid dispersal of invasive species in rivers , while drought extremes reduce river connectivity, threatening biodiversity in rivers  .
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report