What primarily influences the shift from blue-green dominance to desirable green algae?

The shift from blue-green dominance to desirable green algae is primarily influenced by nutrient pollution. Blue-green algae, or cyanobacteria, often thrive in conditions rich in nutrients, particularly phosphorus and nitrogen. When these nutrients are present in high concentrations, they can lead to algal blooms dominated by blue-green species, which can be harmful to aquatic ecosystems.

In contrast, desirable green algae, such as those from the Chlorophyta group, typically flourish under different nutrient regimes that are less conducive to blue-green algae dominance. When nutrient levels are balanced and not excessively high, the conditions favor the growth of green algae over blue-green fractions. This transition can occur as improvements are made in managing nutrient inputs, whether through reducing agricultural runoff or implementing better waste management practices.

Aeration methods, fish predation, and water clarity can have effects on algae in aquatic systems, but their roles are secondary compared to the fundamental influence of nutrient status. For instance, while fish predation may help control algal populations by affecting zooplankton dynamics, it does not directly address nutrient levels. Similarly, aeration methods can improve water clarity and oxygen levels but do not necessarily change the prevailing nutrient conditions. Water clarity can influence light availability for growth, but again, it is the