Rising temperature due to global warming is fatal for life on earth

Aqua culture is becoming a popular business these days and accordingly, freshwater prawn farming has become a precious sector. The production of Macrobrachium rosenbergii (a giant prawn) jumped from 26, 588 MT in 1991 to 118, 501 MT in 2000, globally¹. But unfortunately, prawns have to face different stressors during culture condition, which restrains their yield².

Temperature virtually influences all levels of membrane permeability, biological organization, cellular, tissue and organ function as well as integration in the whole organism. Increasing temperature up to a certain limit supports aquaculture by decreasing the time needed to produce marketable sized animals as well as more generations in a year. However, exceeding threshold limit, temperature is lethal and can cause stress in the organism that consequently leads towards permanent cellular alterations³.

Temperature of this planet is amplifying day by day due to global warming therefore; biological responses of different organisms should be assessed in case of changing environmental conditions. In aquatic life, gills are considered as fundamental structures, as they are involved in gaseous exchange and excretion of nitrogenous compounds⁴ as well.

Hence, these structures can be efficiently used to study environmental changes on the test animals. Accordingly, a new research was carried out to study the cellular alteration of M. rosenbergii gills in response to thermal acclimation at three different temperatures (25, 30 and 35°C) and exposure to thermal extremes as well by using transmission electron microscopy⁵.

Tested prawns were exposed to a steady rate of increase or decrease (0.3°C/min) until critical thermal maxima and critical thermal minima were reached. Afterwards, research team dissected the gills and processed them for transmission electron microscopy, both at the end of acclimation period as well as at critical thermal limits⁵.

This study exhibited that cellular integrity gets changed in the gills, in response to thermal acclimation and exposure to thermal extremes. Conclusively, it is obvious that exposure to mounting temperatures (35°C and above) for longer duration because of global warming and climatic alteration scan lead towards respiratory stress and breakdown of compensatory general adaptive syndrome (GAS) and eventually endanger M. rosenbergii.

Key words: aqua culture, freshwater prawns, Macrobrachium rosenbergii, gills, global warming, general adaptive syndrome, thermal acclimation

References:

1. FAO, 2002. Fisheries statistics-Aquaculture production 2000. Food and Agriculture Organization, Rome.
2. Manush, S.M., A.K. Pal, T. Das and S.C. Mukherjee, 2005. Dietary high protein and vitamin C mitigate stress due to chelate claw ablation in Macrobrachium rosenbergii males. Comp. Biochem. Physiol. Part A: Mol. Integr. Physiol., 142: 10-18.
3. Egginton, S. and B.D. Sidell, 1989. Thermal acclimation induces changes in subcellular structure of fish skeletal muscle. Am. J. Physiol., 256: 1-9.
4. Sayer, M.D.J. and J. Davenport, 1987. The relative importance of the gills to ammonia and urea excretion in five seawater and one freshwater teleost species. J. Fish. Biol., 31: 561-570.
5. S.M. Manush, A.K. Pal, T. Das, N. Chatterjee, K. Sarma and S.C. Mukherjee, 2007. Ultrastructural Alterations in the Gills of Macrobrachium rosenbergii Acclimated to Three Temperatures. Asian J. Cell Biol., 2: 1-10.