[Ecology] Summary of ‘Ecology of a Changing Planet’, Chapter 12

Open-ocean productivity is generally less than 100 g C/m^2/year, but upwellings and continental shelf areas may be two to three times as productive.

Coral reefs are closed nutrient systems that maintain high rates of productivity under oligotrophic conditions. Under eutrophic conditions they may be outcompeted by other organisms like algae and zooplanktons.

Water bodies can be vertically thermally stratified into epilimnion, thermocline and hypolimnion.

Old lakes are lost through geological factors and hydrarch succession, and new lakes are formed by glaciers, rivers, chemical dissolution, and volcano activity.

Different communities of aquatic life will be found according to the nutrient levels and temperature and oxygen profiles of lakes.