While acute stressors can be detrimental, environmental stress conditioning can improve performance. To test the hypothesis that physiological status is altered by stress conditioning, we subjected juvenile Pacific geoduck, Panopea generosa, to repeated exposures of elevated pCO₂ in a commercial hatchery setting followed by a period in ambient common garden. Respiration rate and shell length were measured for juvenile geoduck periodically throughout short-term repeated reciprocal exposure periods in ambient (~550 μatm) or elevated (~2400 μatm) pCO₂ treatments and in common, ambient conditions, 5 months after exposure. Short-term exposure periods comprised an initial 10-day exposure followed by 14 days in ambient before a secondary 6-day reciprocal exposure. The initial exposure to elevated pCO₂ significantly reduced respiration rate by 25% relative to ambient conditions, but no effect on shell growth was detected. Following 14 days in common garden, ambient conditions, reciprocal exposure to elevated or ambient pCO₂ did not alter juvenile respiration rates, indicating ability for metabolic recovery under subsequent conditions. Shell growth was negatively affected during the reciprocal treatment in both exposure histories; however, clams exposed to the initial elevated pCO₂ showed compensatory growth with 5.8% greater shell length (on average between the two secondary exposures) after 5 months in ambient conditions. Additionally, clams exposed to the secondary elevated pCO₂ showed 52.4% increase in respiration rate after 5 months in ambient conditions. Early exposure to low pH appears to trigger carryover effects suggesting bioenergetic re-allocation facilitates growth compensation. Life stage-specific exposures to stress can determine when it may be especially detrimental, or advantageous, to apply stress conditioning for commercial production of this long-lived burrowing clam.

中文翻译：

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短期暴露于酸化海水中的太平洋象拔蚌帕诺豌豆幼鱼的代谢恢复和代偿性壳生长

尽管急性压力源可能有害，但环境压力调节可以改善性能。为了检验生理状况会因压力调节而改变的假说，我们在商业孵化场中对太平洋象拔蚌幼年大熊猫Panopea generosa反复暴露了升高的p CO ₂，然后在环境普通花园中放置了一段时间。在环境（〜550μatm）或升高（〜2400μatm）的p CO _2中，在整个短期反复的相互反复暴露周期中，定期测量幼年象鸭的呼吸速率和壳长暴露后5个月的治疗以及一般的环境条件。短期暴露期包括最初的10天暴露期，然后在环境中暴露14天，然后再进行6天的对等暴露期。最初暴露于升高的p CO ₂相对于环境条件显着降低了呼吸速率25％，但未检测到对壳生长的影响。在公共花园中放置14天后，环境条件下，相互接触升高的或环境中的p CO ₂不会改变青少年的呼吸速率，这表明在随后的条件下能够进行代谢恢复。在两种接触史中，在对等处理期间，壳的生长均受到不利影响。然而，蛤s暴露于最初的升高在环境条件下5个月后，p CO ₂显示出补偿性生长，壳长（两次二次暴露之间的平均值）增加了5.8％。另外，暴露于升高的次级蛤蜊p CO ₂在环境条件后5个月显示出呼吸率52.4％的增加。早期暴露于低pH值似乎会触发残留效应，表明生物能的重新分配促进了生长补偿。生命阶段特定的压力暴露可以确定何时将应力调节应用于这种长寿命穴居蛤的商业化生产可能特别有害或有利。