(b) Mean rainfall (mm) in Dec, 2010/Oct, 2011- data obtained from

(b) Mean rainfall (mm) in Dec, 2010/Oct, 2011- data obtained from Bureau of Meteorology, Government of Australia In Central Queensland, spring and this website summer seasons (November, 2010 to March, 2011) are accompanied by heavy rainfall. Figure 8 (b)

shows the mean rainfall of each month from Dec, 2010 to Oct 2011. Figure 8 (a) showed the turbidity levels of the pond water varied over the range 8–76 NTU during the period Dec, 2010- Oct, 2011. Comparing the data from Figure 8 (a) and (b), it can be determined that the turbidity EPZ015666 molecular weight levels were lowest (8–16 NTU) during the summer period which is linked to heavy rainfall conditions, with a high mean rainfall of 180 mm in Jan, 2011. During winter minimal rainfall was observed with a low in August of 22 mm of around rain when the turbidity level was high, at 76 NTU. So it is logical to interpret from these observations that the summer season will provide

better microbial photocatalytic inactivation over the winter period due to a combination of high sunlight and lower turbidity. Discussion This study has showed that there was a relatively small effect of pH 7.0 and pH 9.0 on microbial inactivation. pH 5.0 showed a different result in Figure 2 with a lower initial counts. As, the acceptable range of a healthy aquaculture system is within the pH range of 6.5 to 9 [14], the findings from Figure 2 at pH levels of 7.0 and 9.0 demonstrates that there is no major Amisulpride pH effect against A. hydrophila inactivation over this pH range. Rincon and Pulgarin [18] suggested NVP-HSP990 research buy that

modifications of water pH between 4 and 9 had no effect on photocatalytic batch culture solar disinfection of E. coli. However, the catalyst would be more negatively charged at high pH and the result is therefore not as might be predicted on the basis of charge alone, indicating that other factors must be involved. To clarify the reduced initial count at pH 5.0 in Figure 2, a longer-term storage experiments was performed over 9 h (Figure 3) to find out the survival capacity of A. hydrophila at pH levels of 5.0, 7.0 and 9.0. This illustrated that in darkness, pH 5.0 negatively affected the survival of A. hydrophila. Some previous aquaculture studies provided evidences that low pH levels are not suitable for growth and survival of fish species [6, 13, 42]. Therefore, the result at pH 5.0 is of less direct relevance to aquaculture systems, since this is not within the usual range of operations. Fresh water ponds, tanks and cages provided 60% of the total aquaculture production of the world in 2008 [43]. Similarly, coastal ponds and tanks also produce fish, molluscs, crustaceans etc. In warm regions, prawns and shrimps mainly dominate the world’s total aquaculture production, 58% of which comes from brackish water supply [44].

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