| With the increasing destruction of the ecological environment,the acidification of seawater has been paid more and more attention,which has brought negative effects to marine organisms.The Cyclina sinensis were fed on 3 independent water cycle system,whose p H were 8.3(control group)and 7.4±0.05,7.7±0.05(treatment group),to study the effects of different levels of a cidification of seawater on Respiratory metabolism,energy budget,immune system and growth survival.And the p H of treatment group were regulated by rushing into air and carbon dioxide.The study could provide a theoretical basis for the breeding of C.sinensis to cope with the increasing acidification of seawater.The results are as follows:1 The changes of oxygen consumption rate and ammonia excretion rate index in the acidification period of 0 d,10 d,20 D,30 d and 40 d were determined and the O :N value was calculated to study the effects of seawater acidification on respiratory metabolism of Cyclina sinensis.The results show that the oxygen consumption rate decreased with rising p H,and lower p H of water promoted the ammonia excretion rate of C.sinensis;O :N value decreased with the decreasing of p H.The resultes indicating that the energy was supplied by its protein in the late of seawater acidification of C.sinensis culture.But with the acidification stress time increaseing,it will regulate its metabolism to adapt to sea acidification..2 The clearance rate,assimilation rate were determined and scope for growth was calculated to study the effects of seawater acidification on energy budget of Cyclina sinensis.The results showed that with the increas ing of acidification time,the filtration rate was significantly reduced,and there were significant difference at 10 d and 30 d(P<0.05).Assimilation rate was inhibited by acidification,the results showed that assimilation rate of treatment group were increasing firstly and then decreasing with the increasing acidification time,but there was no significant difference comparing to control group(p H8.3)(P>0.05).The Scope for growth(SFG)was effected significantly by acidification.The difference between the control group(p H7.4 and 7.7)and the control group(p H8.3)was significant(P<0.05).Energy budget was negative,because the respiratory metabolism of C.sinensis strengthen at 30 d.It more clearly expressed acidification negative impacts on the energy budget of C.Sinensis by using the energy balance diagram depicts the accumulation of energy metabolism in each period the proportion of C.Sinensis.3 The cell immunity,humoral immunity and antioxidant enzymes were determined to study the effects of seawater acidification on immune system of Cyclina sinensis.In view of cellular immunity,the total number of cells,the stability of cell membrane and the effect of phagocytosis were measured.The total number of blood cells decreased with the increas ing of acidification,and the difference was significant(P<0.05).In the short term,the acidification of seawater promoted the stability of blood cell membrane,and increased the stability of cell membrane.The phagocytic effect was similar to that of the total number of blood cells.It decreased with the decreasing of p H,there was significant difference only at 21 d(P<0.05).In exploring the seawater acidification on humoral immunity of C.sinensis,lysozyme,ALP and ACP were measured.The results showed that lysozyme also decreased with the increasing of acidification,but the difference was not significant(P>0.05).Acid phosphatase(ACP)and alkaline phosphatase(ALP),although both belong to phosphatase,showed different trends in seawater acidification.The main difference was that at 28 d ACP decreased,an the control group was higher than that of treatment group.ALP was contrary to,ACP at 28 d.The reasons may be: the decreasing of p H induced ALP activity to resist the decreasing of p H of water environment,which was a self stress performance..However,the difference of both were not significant(P>0.05).The influence of ocean acidification on antioxidant indexes of C.sinensis,superoxide dismutase(SOD),the determination of catalase(CAT)and malondialdehyde(MDA)were determined.SOD and CAT were affected by different degrees of acidification.At the initial stage of acidification,the SOD activity was increased,and the activity of SOD decreased in the later stage.However,the change of CAT was opposite,it decreased at 21 d and then rised at the 28 d.The lipid peroxidation productmalondialdehyde(MDA)reduced significantly In the latter period of the experiment(P<0.05).However,it can not be concluded that the decrease of MDA was caused by the acidification,which may be due to the transient increasing of CAT activity or the non enzymatic reaction.4 The cumulative death number,shell length and shallweight were determined to study the effects of seawater acidification on survival of Cyclina sinensis.The results showed that there was death firstly at treatment group of p H7.4.With the strengthening of seawater acidification,the cumulative number of deaths increased,it was a positive correlation.The mortality rate were p H7.4>p H7.7>p H8.3;The shell length and weight were decreasing with the acidification incraesing.There was a significant inhibitory effect of acidification on the growth of C.sinensis.Within a certain range of ocean acidification will affect the survival and metabolism of C.sinensis,but these effects were not fatal.Thus,ocean acidification has a negative effect on respiration metabolism,energy budget,immune system,growth and survival of Cyclina sinensis. |
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