Technical Note: Low Cost Mesocosms Design for Studies of Tropical Marine Environments

Abstract. Mesocosms are an alternative to in situ ocean environmental studies which are very difficult to implement due to the challenges that the aquatic environment impose. The design of a mesocosm should consider as many variables as possible of the ecosystem to be studied, in order to obtain results that are similar to those that would be obtained in the environment. The effects of tropical climatic conditions on a mesocosm enclosure were studied in order to evaluate their possible influence on the biological community. The mesocosm was equipped with an electric marine thruster as a means of avoiding stratification in the water contained in it. Also, the system is submerged in water to increase the thermal inertia and maintain the temperature variations within reasonable ranges. The design does not include auxiliary forcing cooling systems. The results revealed the influence of climatology on the mesocosms’ temperature and showed the feasibility of the proposed design in tropical environments. With high variations of ambient temperature (> 20 ºC, during the day), the variations in the mesocosm temperature were only 3 ºC. The range of temperature variations were similar to those that occur in certain tropical environments.