SEASONAL VARIATIONS IN THE PHYSICO-CHEMICAL AND BIOLOGICAL PROPERTIES OF A TROPICAL SHALLOW POND

Abstract

NASAR, S.A.K. and JAYASHREE DATTA-MUNSHI (Ecol. Res. Lab., Post-Graduate Dept. Zool., Bhagalpur Univ., Bihar, India) Seasonal variations in the physico-chemical and biological properties of a tropical shallow pond. Jap. J. Ecol. 24,255-259 (1974) The physico-chemical factors of a tropical fresh water shallow pond in Bhagalpur (India) have been studied along with seasonal variations of plankton and discussed in the present communication. (1) Basing upon the abiotic environmental characteristics and the biotic nature, the shallow pond surveyed can be judgd to be one of the "eutrophic" water areas. (2) The considerable fluctuation of dissolved okygen has been correlated with the seasonal changes of macrophytic biomass of the pond. (3) The absence of free CO_2 and abundance of macrophytes, plankton and air-breathing fishes indicate that free CO_2 is not a conditioning factor for their production and growth. (4) Phosphate in the pond soil was not entirely absorbed by the profuse growth of macrophytes even during the intensive photosynthesis. (5) The fishes found in the pond are mostly air-breathing and provided with accessory respiratory organs. Some of the weed fishes have indirect food relation with the macrophytes, because they harbour all types of live food organimsms of fishes. These fishes also use the macrovegetation for shelter and breeding purposes. (6) Such type of ponds infested with macrophytes is suitable for the inhabitation of air-breathing fishes.