Good discussion. I have a couple comments about comments above.
1. Apr 22 2:52 - Ted says- "Bill the only time I see over aeration (overcirculation) a problem is if over heating the water can cause a problem for cool and cold water types Also turns over once per day can be a problem in establishing a bloom when fertilizing for such." I assume Ted means cool-cold water types of fish. But there are usually a lot of other organisms that thrive in the cool-cold water conditions. As the pond warms or cools the composition of the community changes especially the smaller species such as bacteria, algae and invertebrates. Changes happen by species increasing and decreasing based on ambient conditions. When conditions become severe or extreme even largest species (fish) are lost (fish kills). One negative impact that aeration has on blooms is it moves surface algae deep into the water column where sunlight is low or dark. No light no photosynthesis. Another negative is water movement. Many bloom forming species like still or calm water. Moving water tends to slow their reproductive rate which can be good or bad or neutral - depending. Some plankonic species are 'okay' with moving water. However most prefer somewhat calmer conditions. Blooms can definately occur in aerated ponds. The amount or strength of aeration (turns/day) can be important.
2. Apr 22 4:10, g1fiddle says "Let's assume no fertilizer...I thought aeration would provide additional oxygen to facilitate these blooms." For clarification: Oxygen is not really used by plants for photosynthesis. For photosynthesis, plants use carbon dioxide, some nutrients and water in the presence of sunlight to make food, i.e. grow, reproduce, storage. Small amounts of oxygen are used by plants (blooms) continuously for respiration ("breathing") and metabolic activity. During normal conditions plants produce a lot more oxygen than they use. The oxygen primarily benefits all those consumers of oxygen mostly animals/bacteria; the heterotrophs (heterotrophic) as Amanda mentioned.
3. Amanda says Apr 25 - 9:18 -" Water treatment plants, for example, are aerated to the max since the goal is nutrient reduction. I suspect that if you underaerate, the extra nutrients may encourage cyanobacteria over more tasty algae like diatoms and green algae." Good observation. Current research says, it is the ratio or proportion of nutrients in the water column that determines or favors certain species of algae. Thousands of types/species of algae are present, many have 'favorite' nutrient conditions or a special balance where they thrive. As the nutrient balance changes so change the algae. If seeded into the system, certain species will bloom when the nutrient balance and other conditions (temp, day length, etc.) favor their growth.
As Ted indicates above, all this bloom-aeration stuff is a complex interaction of many variables.
Last edited by Bill Cody; 04/25/11 10:14 AM.
