Abstrato

Design and Fabrication of a Hypoxia-Inducing Chamber for Simulation Studies in Environmental Bio-monitoring Using Chironomus larvae

Anupama Ronad and Nath BB

The larvae of the aquatic Chironomid midge (Diptera, Chironomidae) are known to survive in freshwater habitats exposed to stress especially that of hypoxic stress. Hence, a study of the effect of alterations in the levels of dissolved oxygen on the physiology of the larvae could help in establishing them as potential sensitive bio indicators for monitoring such freshwater habitats. A simple inexpensive and non-cumbersome experimental set-up unlike commercially available sophisticated set-ups was designed and fabricated in the lab. The validation of this set-up was carried out and alterations in the hemoglobin levels in the larvae of the tropical midge species Chironomus ramosus exposed to hypoxic conditions were studied. It was observed that there was an increase in the level of hemoglobin on exposure to hypoxic conditions and the findings were further validated by studying the expression of hemoglobin gene at various time points during exposure to hypoxia. These findings suggest that the device designed could be used as an inexpensive and effective method for generating and maintaining the desired levels of dissolved oxygen as compared to several of the chemical and physical methods generally used. Further, this would be useful in studies to be done for the monitoring of hypoxia in freshwater habitats using Chironomus hemoglobin as a biomarker.