Extensive research has shown that the early life stages of marine organisms are sensitive to ocean acidification (OA). Less is known, however, on whether larval settlement and metamorphosis may be affected, or by which mechanisms. These are key processes in the life cycle of most marine benthic organisms, since they mark the transition between the free swimming larval stage to the benthic life. We investigated whether OA could affect the larval settlement success of the sea urchin Evechinus chloroticus, a key coastal species with ecological, economic and cultural importance in New Zealand. We performed four settlement experiments to test whether reduced seawater pH (ranging from 8.1 to 7.0, at an interval of ∼0.2 pH units) alters larval settlement and metamorphosis success. Our results show that settlement success was not significantly reduced when the larvae were exposed to a range of reduced seawater pH treatments (8.1–7.0) at time of settlement (direct effects). Similarly, when presented with crustose coralline algae (CCA) pre-conditioned in different seawater pH of either pH 8.1 or 7.7 for 28 days, larval settlement success remained unaltered (indirect effects). We conclude that competent larvae in this species are resilient to OA at time of settlement. Further research on a range of taxa that vary in settlement selectivity and behaviour is needed in order to fully understand the effects of OA on the life cycle of marine invertebrates and the consequences it might have for future coastal marine ecosystems.

大量研究表明，海洋生物的早期生命阶段对海洋酸化（OA）敏感。然而，关于幼虫的沉降和变态是否会受到影响或受何种机制的影响知之甚少。这些是大多数海洋底栖生物生命周期中的关键过程，因为它们标志着自由游泳幼体阶段到底栖生物之间的过渡。我们调查了OA是否会影响海胆Evechinus chloroticus的幼虫沉降成功，Evechinus chloroticus是新西兰的一种具有生态，经济和文化重要性的重要沿海物种。我们进行了四个沉降实验，以测试降低的海水pH值（范围从8.1至7.0，间隔约为0.2 pH单位）是否会改变幼体的沉降和变态成功。我们的结果表明，在沉降时，将幼体暴露于一系列降低的海水pH处理（8.1-7.0）下，沉降成功不会显着降低（直接影响）。同样，当在不同的海水pH值pH值8.1或7.7中预先处理的硬壳珊瑚藻（CCA）放置28天时，幼虫的定居成功率仍保持不变（间接影响）。我们得出的结论是，定居时该物种的幼虫对OA具有抵抗力。为了充分了解OA对海洋无脊椎动物生命周期的影响及其对未来沿海海洋生态系统的后果，需要对定居点选择性和行为各不相同的一系列分类单元进行进一步研究。0）结算时（直接影响）。同样，当在不同的海水pH值pH值8.1或7.7中预先处理的硬壳珊瑚藻（CCA）放置28天时，幼虫的定居成功率仍保持不变（间接影响）。我们得出的结论是，定居时该物种的幼虫对OA具有抵抗力。为了充分了解OA对海洋无脊椎动物生命周期的影响及其对未来沿海海洋生态系统的影响，需要对定居点选择性和行为不同的一系列分类单元进行进一步研究。0）结算时（直接影响）。同样，当在不同的海水pH值pH值8.1或7.7中预先处理的硬壳珊瑚藻（CCA）放置28天时，幼虫的定居成功率仍保持不变（间接影响）。我们得出的结论是，定居时该物种的幼虫对OA具有抵抗力。为了充分了解OA对海洋无脊椎动物生命周期的影响及其对未来沿海海洋生态系统的后果，需要对定居点选择性和行为各不相同的一系列分类单元进行进一步研究。我们得出的结论是，定居时该物种的幼虫对OA具有抵抗力。为了充分了解OA对海洋无脊椎动物生命周期的影响及其对未来沿海海洋生态系统的后果，需要对定居点选择性和行为各不相同的一系列分类单元进行进一步研究。我们得出的结论是，定居时该物种的幼虫对OA具有抵抗力。为了充分了解OA对海洋无脊椎动物生命周期的影响及其对未来沿海海洋生态系统的后果，需要对定居点选择性和行为各不相同的一系列分类单元进行进一步研究。