Eastland...

You can think of a pond bottom like a septic tank. In fact, there is a thread about using septic chemicals to reduce pond sludge on this site. Anaerobic bacteria can decompose sludge, but are very inefficient at doing it. When you add aeration to the pond, aerobic bacteria as well as anaerobic bacteria are able to decompose the organic sludge. This makes the decomposition many times more efficient. Some people have even posted about adding One Flush to their ponds that have aeration and have had noticeable results.

Water dries, rocks crumble, and trees die. The only thing that is eternal is the reputation we leave behind.
- Ancient Viking Proverb