Facultative Ponds (Cont.)

Remember that the two layers, or strata, of a facultative pond are the aerobic zone and the anaerobic zone. The depth of each zone will vary based on the environment conditions, such as ambient temperature and wind speed. While most processes within the two strata work independently of one another, there is complex interaction between these two separate communities. The exchange of soluble organic matter and nutrients connects them.

In the aerobic zone, algae utilize sunlight, carbon dioxide, nutrients, and ammonia. Algae emit dissolved oxygen as a by-product of this process. The dead algae cells then become part of the organic food matter of the ecosystem. The aerobic bacteria utilize oxygen and influent organic matter.

In the anaerobic zone, bacteria utilize influent organic matter. They emit water, carbon dioxide, nutrients, ammonia, alkalinity, hydrogen sulfide, and methane as waste products. First, acid forming bacteria break down organic matter in organic acids, then methane producing bacteria feed or the organic acids and convert them to carbon dioxide, water, and methane gas.