Seawater carbonate chemistry and hatching rate, malformation rate, metamorphosis rate and shell growth of the Pacific abalone in a laboratory experiment

The hatching process of the Pacific abalone Haliotis discus hannai was prolonged at a pH of 7.6 and pH 7.3, and the embryonic developmental success was reduced. The hatching rate at pH 7.3 was significantly (10.8%) lower than that of the control (pH 8.2). The malformation rates at pH 7.9 and pH 8.2 were less than 20% but were 53.8% and 77.3% at pH 7.6 and pH 7.3, respectively. When newly hatched larvae were incubated for 48 h at pH 7.3, only 2.7% of the larvae settled, while more than 70% of the larvae completed settlement in the other three pH treatments. However, most 24 h old larvae could complete metamorphosis in all four pH treatments. Overall, a 0.3-unit reduction in water pH will produce no negative effect on the early development of the Pacific abalone, but further reduction in pH to the values predicted for seawater by the end of this century will have strong detrimental effects.

本研究针对太平洋鲍（Haliotis discus hannai）的早期发育开展实验，结果显示：当水体pH分别为7.6与7.3时，其孵化进程显著延长，胚胎发育成功率随之下降。pH 7.3组的孵化率较对照组（pH 8.2）显著降低10.8%。pH 7.9与pH 8.2组的幼体畸形率均低于20%，而pH 7.6与pH 7.3组的畸形率分别高达53.8%与77.3%。将初孵幼体在pH 7.3水体中培育48小时后，仅2.7%的幼体完成附着，其余三个pH处理组的幼体附着率均超过70%。但在所有四个pH处理组中，培育24小时的幼体均可顺利完成变态发育。综合来看，水体pH降低0.3个单位不会对太平洋鲍的早期发育产生负面影响，但若将pH进一步降至本世纪末海水pH预测值，则会对其产生强烈的不利影响。