Effects of seawater acidification on early development of the intertidal sea urchin Paracentrotus lividus, seawater carbonate chemistry and biological processes

The effect of pH ranging from 8.0 to 6.8 (total scale - pHT) on fertilization, cleavage and larval development until pluteus stage was assessed in an intertidal temperate sea urchin. Gametes were obtained from adults collected in two contrasting tide pools, one showing a significant nocturnal pH decrease (lowest pHT = 7.4) and another where pH was more stable (lowest pHT = 7.8). The highest pHT at which significant effects on fertilization and cleavage were recorded was 7.6. On the contrary, larval development was only affected below pHT 7.4, a value equal or lower than that reported for several subtidal species. This suggests that sea urchins inhabiting stressful intertidal environments produce offspring that may better resist future ocean acidification. Moreover, at pHT 7.4, the fertilization rate of gametes whose progenitors came from the tide pool with higher pH decrease was significantly higher, indicating a possible acclimatization or adaptation of gametes to pH stress.

本研究针对一种潮间带温带海胆，探究了范围为8.0至6.8的总pH值（pHT）对其受精、卵裂以及至长腕幼虫（pluteus）阶段的幼体发育的影响。本研究从两处特征迥异的潮池采集成年海胆，获取其配子：其中一处潮池夜间pH显著下降，最低pHT为7.4；另一处潮池pH较为稳定，最低pHT为7.8。对受精与卵裂产生显著影响的最高pHT阈值为7.6。与之相反，幼体发育仅在pHT低于7.4时才会受到影响，该阈值与多种潮下带物种的相关报道数值相当或更低。这表明栖息于胁迫性潮间带环境的海胆，其后代或可更好地抵御未来海洋酸化。此外，在pHT为7.4的条件下，亲本采自pH降幅更大的潮池的配子，其受精率显著更高，这表明配子或已对pH胁迫产生了适应性驯化或遗传适应。