Lake Stratification and Eutrophication: How Summer Layers Drive Algal Blooms #2173131 (License: Personal Use)

This diagram illustrates thermal stratification in lakes during summer, where the warmer, less dense epilimnion floats atop the cooler, denser hypolimnion, preventing vertical mixing. As organic matter sinks and decomposes in the hypolimnion, bacteria consume dissolved oxygen and release ammonium and phosphorus-nutrients that, when upwelled or mixed later, trigger phytoplankton and cyanobacteria blooms. Cyanobacteria gain a competitive edge by fixing atmospheric nitrogen when other nutrients are limited.

Used in environmental science education, water quality reports, and ecology web content to explain eutrophication, dead zones, and seasonal algal bloom dynamics; matches user intent for understanding lake health, climate impacts, or managing reservoirs.