Effects of different pCO2 concentrations on marine bacterial community structure, Eastern Harbor, Alexandria, Egypt
The direct effect of an elevated CO2 concentration range (280, 385, 550, 750 and 1050 µatm) on the marine bacterial counts and dominancy of species were examined. Our results demonstrated that the variation in glucose consumption corresponding to the incubation period (h) of bacterial community structure showed that glucose degradation as a carbon source for bacteria is in good consistency with the total bacterial count pattern. Glucose uptake and oxygen consumption are increased by increasing the temperature from 28 to 35°C and also by increasing pCO2 from nowadays pCO2 (385µatm) to (1050 µatm). The highest consumption of glucose and oxygen was recorded in consistence with the dominancy of glucose degrading bacteria. The dominant bacterial species isolated from the Eastern Harbor, Alexandria, Egypt were counted and genetically identified. The total bacterial count (CFU/ml) increased linearly with increasing different pCO2 at 35°C from 280 and 1050, respectively. Total bacterial count (CFU/ml) at different pCO2 increased linearly with the incubation temperature (28-35°C). There were seven bacterial isolates from the Eastern Harbor with codes (HW1-HW7). They were affiliated according to their 16S rDNA to Bacillus cereus HW1, Psychrobacter maritimus HW2, Shima marina HW3, Pseudoalteromonas atlanticaHW4, Bacillus horikoshii HW5, Oceanicola marinus HW6 and Oceanicola nanhaiensis HW7, respectively. Oceanicola nanhaiensis HW7 exhibited fluctuation in hydrolytic activities against several carbon sources. The highest activity was for lipase followed by agarase, while the lowest activity was for cellulase. This It is also concluded that ocean acidification will impact bacterial organic matter degradation by changing reaction velocities of extracellular enzymes.
Ibrahim HAH, El-Sayed WMM, Shaltout NA, El-Shorbagi EK, 2014: Effects of different pCO2concentrations on marine bacterial community structure, Eastern Harbor, Alexandria, Egypt, Life Sci J 2014;11(10):781-789. Article.