ASGSB 1998 Annual Meeting Abstracts

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THE DESIGN AND FUNCTION OF A CLOSED MARINE ECOSYSTEM FOR SPACE FLIGHT. J.R. Ascher¹, O. Van den Ende², and D. Thomas³. ¹Chemistry Dept., University of South Florida, Tampa, FL; ²Bionetics Corporation, Kennedy Space Center, FL; ³Dept. Of Biological Sciences, University of Idaho, Moscow, ID.

Closed systems are good models for ecosystems on the earth, a very large closed system, or for systems used for life support in a closed environment, such as in a space station.

Our first objective was to create a passive closed marine ecosystem for space flight using existing hardware. After devising a system, we used Nannochloris oculata, Gracilaria , and Artemia salina to determine the optimum Artemia density with a constant amount of both algae.

A Plant Growth Chamber, used in previous shuttle flights, was modified to support a closed marine system by lining with a sealed bag. In the first trial three densities of Artemia were used and the optimum density was 93 Artemia per liter of solution. The first trial was run with the capability of removing solution for chemical analysis. Light and temperature were controlled. Algal cell concentration, pH and ammonia levels were measured. Artemia population was determined. In the second trial the optimum density of Artemia was placed into each chamber and the bag was completely sealed and kept at 25 C to simulate space flight conditions.

In trial 1 survival rates went down as population density of Artemia went up, and the differences were statistically significant. In trial 2 the survival rate of Artemia was higher than any of the three groups in trial 1. Nannochloris oculata concentrations increased as Artemia population decreased. Variations in pH and ammonia levels were not statistically significant between groups.

The results of this experiment indicate that a closed marine ecosystem could be successfully sustained on earth in existing space flight hardware with only a light source. Further tests are indicated to assure the stability of the experimental design in micro-gravity. (Supported by the NASA Space Life Sciences Training Program.)

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