The effects of trans-generational exposure to ocean warming and acidification on life history and physiological traits in a marine polychaete

Human-assisted, trans-generational exposure to ocean warming and acidification has been proposed as a conservation and/or restoration tool to produce resilient offspring. To improve our understanding of the need for and the efficacy of this approach, we characterised life history and physiological responses in offspring of the marine polychaete Ophryotrocha labronica exposed to predicted ocean warming (OW: + 3 °C), ocean acidification (OA: pH -0.5) and their combination (OWA: + 3 °C, pH -0.5), following the exposure of their parents to either control conditions (within-generational exposure) or the same conditions (trans-generational exposure). Trans-generational exposure to OW fully alleviated the negative effects of within-generational exposure to OW on fecundity and egg volume and was accompanied by increased metabolic activity. While within-generational exposure to OA reduced juvenile growth rates and egg volume, trans-generational exposure alleviated the former but could not restore the latter. Surprisingly, exposure to OWA had no negative impacts within- or trans-generationally. Our results highlight the potential for trans-generational laboratory experiments in producing offspring that are resilient to OW and OA. However, trans-generational exposure does not always appear to improve traits, and therefore may not be a universally useful tool for all species in the face of global change.

人工调控的海洋变暖（ocean warming, OW）与酸化（ocean acidification, OA）跨代暴露策略，已被提议作为培育抗逆子代的保护或修复工具。为深化对该策略必要性与应用效果的认知，本研究以海洋多毛类（polychaete）*Ophryotrocha labronica*为实验对象，设置两类亲代预处理：亲代暴露于对照条件（对应子代仅自身承受胁迫的代内暴露组），或亲代暴露与子代相同的胁迫条件（对应亲代与子代均承受胁迫的跨代暴露组）；随后将各组子代分别暴露于预测的海洋变暖（OW：升温3℃）、海洋酸化（OA：pH降低0.5）及其复合胁迫（OWA：升温3℃、pH降低0.5）环境，最终表征子代的生活史与生理响应特征。
跨代暴露于海洋变暖，可完全抵消代内暴露于海洋变暖对繁殖力与卵体积的负面影响，同时伴随代谢活性的提升。尽管代内暴露于海洋酸化会降低幼体生长速率与卵体积，但跨代暴露可缓解前者的负面影响，却无法修复后者。令人意外的是，复合胁迫OWA无论在代内还是跨代暴露条件下，均未产生负面影响。
本研究结果表明，跨代暴露实验在培育耐海洋变暖和酸化的子代方面具有应用潜力。但跨代暴露并非总能提升相关性状，因此在全球变化背景下，该策略并非适用于所有物种的通用工具。