The Swire Institute of Marine Science and Area of Ecology and Biodiversity, School of Biological Sciences, The University of Hong Kong, Hong Kong SAR, China.
Institute for Climate and Carbon Neutrality, The University of Hong Kong, Hong Kong SAR, China.
Glob Chang Biol. 2022 Oct;28(19):5781-5792. doi: 10.1111/gcb.16339. Epub 2022 Aug 3.
With rising ocean temperatures, extreme weather events such as marine heatwaves (MHWs) are increasing in frequency and duration, pushing marine life beyond their physiological limits. The potential to respond to extreme conditions through physiological acclimatization, and pass on resistance to the next generation, fundamentally depends on the capacity of an organism to cope within their thermal tolerance limits. To elucidate whether heat conditioning of parents could benefit offspring development, we exposed adult sea urchins (Heliocidaris erythrogramma) to ambient summer (23°C), moderate (25°C) or strong (26°C) MHW conditions for 10 days. Offspring were then reared at constant temperature along a thermal gradient (22-28°C) and development was tracked to the 14-day juvenile stage. Progeny from the MHW-conditioned adults developed through to metamorphosis faster than those of ambient conditioned parents, with most individuals from the moderate and strong heatwaves developing to the larval stage across all temperatures. In contrast, the majority of offspring from the control summer temperature died before metamorphosis at temperatures above 25°C (moderate MHW). Juveniles produced from the strong MHW-conditioned adults were also larger across all temperatures, with the largest juveniles in the 26°C treatment. In contrast, the smallest juveniles were from control (current-day summer) parents (and reared at 22 and 25°C). Surprisingly, initial survival was higher in the progeny of MHW exposed parents, even at temperatures hotter than predicted MHWs (28°C). Importantly, however, there was substantial mortality of juveniles from the strong MHW parents by day 14. Therefore, while carryover effects of parental conditioning to MHWs resulted in faster growing, larger progeny, this benefit will only persist beyond the more sensitive juvenile stage and enhance survival if conditions return promptly to normal seasonal temperatures within current thermal tolerance limits.
随着海洋温度的升高，海洋热浪（MHWs）等极端天气事件的频率和持续时间都在增加，这使得海洋生物超出了它们的生理极限。通过生理适应来应对极端条件并将抵抗力传递给下一代的潜力，从根本上取决于生物体在其温度容忍极限内的应对能力。为了阐明父母的热驯化是否能使后代的发育受益，我们将成年海胆（Heliocidaris erythrogramma）暴露于环境夏季（23°C）、温和（25°C）或强烈（26°C）的海洋热浪条件下 10 天。然后，将后代在恒定温度下沿着温度梯度（22-28°C）进行培养，并跟踪其发育至 14 天的幼体阶段。与环境条件下的亲代相比，来自 MHW 条件下的亲代的后代更快地发育到变态期，大多数来自温和和强烈热浪的个体在所有温度下都发育到幼虫阶段。相比之下，在 25°C 以上的温度下（温和 MHW），来自对照夏季温度的大多数后代在变态前死亡。来自强烈 MHW 条件下的亲代的幼体在所有温度下也更大，在 26°C 处理下的幼体最大。相比之下，最小的幼体来自对照（当前夏季）亲代（在 22 和 25°C 下饲养）。令人惊讶的是，即使在比预测的 MHW 更热的温度下，暴露于 MHW 的亲代后代的初始存活率也更高。然而，重要的是，强烈 MHW 亲代的幼体在第 14 天有大量死亡。因此，虽然亲代对 MHW 的驯化的后续效应导致生长更快、更大的后代，但只有在更敏感的幼体阶段之后，并且在当前温度容忍极限内的季节温度迅速恢复正常的情况下，这种益处才会持续并提高存活率。
