Institute of Physiology, Christian-Albrechts-University Kiel, Kiel, Germany.
Department of Collective Behaviour, Max Planck Institute for Ornithology, Radolfzell, Germany.
Acta Physiol (Oxf). 2018 Oct;224(2):e13075. doi: 10.1111/apha.13075. Epub 2018 May 9.
Experimental simulation of near-future ocean acidification (OA) has been demonstrated to affect growth and development of echinoderm larval stages through energy allocation towards ion and pH compensatory processes. To date, it remains largely unknown how major pH regulatory systems and their energetics are affected by trans-generational exposure to near-future acidification levels.
Here, we used the common sea star Asterias rubens in a reciprocal transplant experiment comprising different combinations of OA scenarios, to study trans-generational plasticity using morphological and physiological endpoints.
Acclimation of adults to pH 7.2 (pCO 3500 μatm) led to reductions in feeding rates, gonad weight and fecundity. No effects were evident at moderate acidification levels (pH 7.4; pCO 2000 μatm). Parental pre-acclimation to pH 7.2 for 85 days reduced developmental rates even when larvae were raised under moderate and high pH conditions, whereas pre-acclimation to pH 7.4 did not alter offspring performance. Microelectrode measurements and pharmacological inhibitor studies carried out on larval stages demonstrated that maintenance of alkaline gastric pH represents a substantial energy sink under acidified conditions that may contribute up to 30% to the total energy budget.
Parental pre-acclimation to acidification levels that are beyond the pH that is encountered by this population in its natural habitat (eg, pH 7.2) negatively affected larval size and development, potentially through reduced energy transfer. Maintenance of alkaline gastric pH and reductions in maternal energy reserves probably constitute the main factors for a reduced juvenile recruitment of this marine keystone species under simulated OA.
实验模拟近未来海洋酸化（OA）已被证明会通过离子和 pH 补偿过程的能量分配来影响棘皮动物幼虫阶段的生长和发育。迄今为止，人们对于主要 pH 调节系统及其能量学如何受到跨代暴露于近未来酸化水平的影响，仍然知之甚少。
在这里，我们使用常见的海星 Asterias rubens 进行了一项互惠移植实验，该实验包含不同的 OA 情景组合，使用形态和生理终点来研究跨代可塑性。
成年海星适应 pH 7.2（pCO3500 μatm）会降低摄食率、性腺重量和生殖力。在中度酸化水平（pH 7.4；pCO2000 μatm）下，没有明显的影响。父母在 pH 7.2 下预适应 85 天，即使幼虫在中等和高 pH 条件下生长，也会降低发育速度，而在 pH 7.4 下预适应不会改变后代的表现。对幼虫阶段进行微电极测量和药理学抑制剂研究表明，在酸化条件下维持碱性胃 pH 值是一个巨大的能量消耗，可能占总能量预算的 30%。
父母在其自然栖息地遇到的 pH 值以外的酸化水平下进行预适应（例如，pH 7.2）会对幼虫的大小和发育产生负面影响，可能是通过减少能量传递。维持碱性胃 pH 值和减少母体能量储备可能是模拟 OA 下这种海洋关键物种幼体数量减少的主要因素。
