Population Dynamics of Copepoda and Cladocera in an Iowa farm pond, Summer 1973

Abstract

The problem. To calculate rates for birth, death, and natural increase of zooplankton found in an unpolluted artificial pond. This will serve as a basis for comparisons with other bodies of water to show man's effect upon one of the most basic of all ecosystems. Procedure. Water samples were collected with a Kemmerer Water Sampler and poured into a plankton net for concentrating the organisms. They were killed in 4% formalin and counted keeping records of species numbers, sex, and reproductive condition. Abiotic factors were also measured and recorded. Findings. The greatest concentration of organisms was always located at the 2.5 meter depth. Species' densities did fluctuate directly with primary productivity after a certain lag period. but no other factor was found to have an influence upon the zooplankton location or density. Conclusion. All of the populations varied greatly, but food had the greatest direct effect upon the densities. Recommendations. It would be necessary to conduct a long term study of the same pond so that a complete understanding could be obtained of development, growth. and extinction of the various populations. For a complete understanding of the zooplankton community, techniques involving evaluations of competition, predation and interreactions between populations should be developed and included.