Short-term and latent post-settlement effects associated with elevated temperature and oxidative stress on larvae from the coral Porites astreoides
Short-term and latent post-settlement effects associated with elevated temperature and oxidative stress on larvae from the coral Porites astreoides
复制标题
与高温和氧化应激对珊瑚滨珊瑚幼虫相关的短期和潜在的定居后影响
作者：
C. Ross;R. Ritson;K. Olsen;V. Paul
在过去30年中，整个加勒比地区的珊瑚礁正在经历前所未有的珊瑚覆盖率下降，珊瑚补充是一个可能有助于珊瑚种群恢复的过程。为了更好地了解气候变化对珊瑚幼虫生态学的影响，对滨珊瑚幼虫进行了研究，以确定高温和相关氧化应激的即时和沉降后的影响。将星状滨珊瑚幼虫暴露于27 °C（环境温度）和+3.0 °C（高温）海水中24 h，然后测定一系列生理参数以确定亚致死胁迫的程度。在+3.0 °C处理后，与维持在27 °C的对照相比，幼虫在PSII的最大量子产率（Fv/Fm）或呼吸需求方面没有显示出显著差异。添加微摩尔浓度的过氧化氢不影响呼吸或光化学效率。与对照相比，幼虫中的过氧化氢酶活性在暴露于升高的温度后增加（> 60%）。短期幼虫的生存和解决和变态不受温度升高或H2 O2处理。然而，当在田间的沉降瓦片上部署4天大的沉降幼鱼后24天检查时，暴露于高温的沉降幼鱼的存活率下降99%，而对照幼鱼的存活率下降90%。这些结果表明，短期暴露于某些应激源可能对珊瑚生理学的影响很小，对幼虫的生存，定居和变态没有影响。然而，由于定居后的死亡率，这些压力可能会导致珊瑚招聘显着减少。
Coral reefs across the Caribbean are undergoing unprecedented rates of decline in coral cover during the last three decades, and coral recruitment is one potential process that could aid the recovery of coral populations. To better understand the effects of climate change on coral larval ecology, the larvae of Porites astreoides were studied to determine the immediate and post-settlement effects of elevated temperature and associated oxidative stress. Larvae of Porites astreoides were exposed to 27 °C (ambient) and +3.0 °C (elevated temperature) seawater for a short duration of 24 h; then, a suite of physiological parameters were measured to determine the extent of sublethal stress. Following the +3.0 °C treatment, larvae did not show a significant difference in maximum quantum yield of PSII (Fv/Fm) or respiratory demand when compared to controls maintained at 27 °C. The addition of micromolar concentrations of hydrogen peroxide did not impact respiration or photochemical efficiency. Catalase activity in the larvae increased (>60 %) following exposure to elevated temperature when compared to the controls. Short-term larval survival and settlement and metamorphosis were not affected by increased temperature or the H2O2 treatment. However, the settled spat that were exposed to elevated temperature underwent a 99 % reduction in survival compared to 90 % reduction for the control spat when examined 24 days following the deployment of 4-day-old settled spat on settlement tiles in the field. These results show that short-term exposure to some stressors might have small impacts on coral physiology, and no effects on larval survival, settlement and metamorphosis. However, due to post-settlement mortality, these stressors can cause a significant reduction in coral recruitment.