List four catastrophic events:

avalanche, earthquake, flood, forest fire, hurricane, lightning, tornado, tsunami and volcanic eruption.

Explanation: Here extra catastrophic events

Hurricane Katrina , the indian ocean tsunami,

Pangaea , and a volcanic eruption

poor water quality affects most estuarine organisms, including commercially important fish and shellfish. the pollutants that have the greatest impact on the health of estuaries include toxic substances like chemicals and heavy metals, nutrient pollution (or eutrophication), and pathogens such as bacteria or viruses.