Pond Boss Forums GENERAL QUESTIONS Pond Boss question about reservoir vs pond

Our local COE reservoir (Beaver) has adequate oxygen for striped bass even at 100 foot plus depths. How is that possible when a pond might have little oxygen at 9 feet? Can't just be wind action, can it?

Excellent question. Folks routinely fish those depths in the Great Lakes. I will be interested in the answer as well.

I thought this would be a question about how is a reservoir different than a lake or pond. When is a water body a reservoir and not a lake or pond?

The question 'at hand': "adequate oxygen for striped bass even at 100 foot plus depths. How is that possible when a pond might have little oxygen at 9 feet?"

This is a limnology type of question and the answer lies in 'lake' productivity and plankton. In fewer terms, the basis of this answer is fertility, how enriched is the water with nutrients - aka eutrophy, enrichment. The more enriched the lake/pond the more plants that it grows. More plants, including phytoplankton and zooplankton there are present, the more ultimate food materials there are for feeding fish - productivity, more fish biomass per acre that is present.

Plants have life cycles and the life span of plankton is short - usually days or weeks, infrequently months. The more plankton there is the more death that occurs and the dead biomass of these organisms sinks. As they sink through the water column they are decomposing - using oxygen. More plankton occurs in enriched water thus there is more plankton death using oxygen as they sink into the deep water.

Low plankton density, nutrient poor, means not much dead plankton rains down into the deep, cold, oxygen rich water (hypolimnion) produced from the spring turnover. Comparatively low plankton density means very slow loss of oxygen in the deeper water. When there is a large volume of deep water and low 'rain out' of dead plankton the DO then lasts all summer until the fall turnover when the deep water is then reoxygenated.

Lakes/ponds that are fertile with heavy plankton blooms almost always lose the oxygen in the deep layer sometimes as shallow as 6 to 9ft. This depends mostly on volume of deep water (hypolimnion) and amount of dead plankton raining down into it. A common exception in my area are abandoned, steep sided, deep stone quarries. Characteristics are low fertility, clear water, low plankton, small littoral area, and low fish biomass/ac due to low productivity. Littoral areas usually generate a lot of dead organisms that decompose using DO. Trout can live all summer in the deepest cold layers of these deep, low nutrient water, stone quarries.

The deep water of Lake Erie now has a summer 'dead zone' i.e. no oxygen. This is due to too much dead plankton, dead biomass, and plants sinking into the deep zone during the summer. Too much dead stuff is a result of too much fertility that grows too much stuff that dies, sinks, and uses DO.

Good information.

very interesting stuff!