If I aerate to reduce the muck on the bottom
does this also reduce the amount of weeds that grow in the pond?If this does reduce the amount
of muck on the bottom how big of an area does it
take care of or does it depend on the system you use.

Hi Kelly -
A good aeration system properly sized for your pond will help to elimate the muck and help control plant and algae growth. By introducing oxygen to the bottom of your pond, aerobic bacteria as well as other benthic organisms will be able to exist and eat away at the organic matter that has accumulated over time. Aerobic bacteria grow and eat 30 times faster than anaerobic bacteria. During this digestion process, CO2 is formed and if properly aerated is pushed up to the surface and released into the atmosphere. If the aeration is not adequate, the CO2 will be mixed into the water column and along with water and sunlight will enable aquatic plants and algae to thrive. Plants also need nutrients such as iron, phosphorus, manganese and nitates. Oxidation limits these nutrients by changing them into their insoluble state therefore rendering them unavailable for plant consumption.
The amount of muck reduced is an unknown at this point. I do know of a large lake in Michigan which is measuring muck reduction since they installed aeration last summer, but I do not have the results yet. The main thing is to find an aeration system that will circulate the entire volume of water in your pond atleast one time per day. Once adequately aerated, all the benefits of a healthy pond will come along.

I think carbon dioxide (CO2), although very important to plant photosynthesis, is very rarely a limiting factor for plant growth in a pond ecosystem. Production of CO2 by diffusion from the atmosphere and by respiration of all living things (plants, and bacteria (decay) plus animals up through fish), is a continual process. Rarely is CO2 ever limiting enough even with aeration to cause significiant reductions of plant growth. Other chemical factors usually become limiting to plant growth before the concentrations of CO2. In buffered waters, CO2 concentrations are usually mediated by dissociation of bicarbonate and carbonate to form an equilibrum. Excess amounts of CO2 are more likely to occur in weakly buffered waters (low alkalinity). It is a well known fact that plant productivity is usually low in alkalinity or weakly buffered waters despite the likelhood of increased concentrations of dissolved CO2.

CO2 concentrations in most lakes and ponds are usually greater than the CO2 conc than that of the atmosphere and these waters release some CO2 by diffusion into the atmosphere.

Aeration is a very good process for maintaining a healthy pond or lake but I am not so sure that aeration is able to limit plant growth by reducing the amount of CO2.

Bill :

Thanks for your comments on CO2 in the pond. It got me to thinking about how little I had seen on the subject. I found the following SRAC Fact Sheet on the subject. A very good read on the matter. It reinforced what you posted as well as the importance of enough alkalinity and aeration and the possible problems of using hydrated lime ( which I don't use but I think some on the forum do).This article does a good job of tying the factors together. ewest

http://srac.tamu.edu/tmppdfs/7107322-468fs.pdf

Here is another fact sheet tying many water quality factors together.

http://srac.tamu.edu/tmppdfs/7107322-464fs.pdf

ewest - thanks for the additional reference for CO2. The discussion was informative about the relationship between dissolved oxygen and CO2.