Designing a Closed Ecological System to Support Animal Populations for Greater than Thirty Days: Palm Sized Ecosystems
The study of closed ecological systems (CES) has wide implications for study of ecological interactions both on earth and in space. Our design problem was to create closed ecological systems that were able to support animal grazer populations for greater than thirty days. CES were developed for freshwater and marine systems, in 75 mL Tissue culture flasks. Systems were studied under various influences, such as different light levels, and after the introduction nutrients into the systems. Results from saltwater systems observed under varying light levels suggest that six hours of light per day was adequate and longer light periods were not beneficial. Results from the nutrient introduction experiment indicate that nitrogen was a limiting factor in the health and survival of Daphnia in freshwater CES, but phosphorus was not.
Most chapters of this book concern interactions of land and water masses, or land-water energy exchanges involving primary and secondary trophic levels. In this chapter I review one example of a land-water interaction at the tertiary trophic level: use of terrestrial invertebrates as food by fish, primarily members of the Salmonidae family. Salmonids (salmon, trout, whitefish, grayling) constitute one of the most important families of sport and commercial fishes, especially in North America, England, and northern Eurasia.