Acid-base physiology over tidal periods in the mussel Mytilus edulis: size and temperature are more influential than seawater pH

Ocean acidification (OA) studies to date have typically used stable open-ocean pH and CO2 values to predict the physiological responses of intertidal species to future climate scenarios, with few studies accounting for natural fluctuations of abiotic conditions or the alternating periods of emersion and immersion routinely experienced during tidal cycles. Here, we determine seawater carbonate chemistry and the corresponding in situ haemolymph acid-base responses over real time for two populations of mussel (Mytilus edulis) during tidal cycles, demonstrating that intertidal mussels experience daily acidosis during emersion. Using these field data to parameterise experimental work we demonstrate that air temperature and mussel size strongly influence this acidosis, with larger mussels at higher temperatures experiencing greater acidosis. There was a small interactive effect of prior immersion in OA conditions (pHNBS 7.7/pCO2 930 µatm) such that the haemolymph pH measured at the start of e...迄今为止的海洋酸化（OA）研究通常采用稳定的开阔海域pH与CO₂数值，预测潮间带物种对未来气候情景的生理响应，仅有少量研究考虑了非生物条件的自然波动，或是潮汐周期中潮间带生物常规经历的暴露与浸没交替过程。本研究针对两个紫贻贝（Mytilus edulis）种群，在潮汐周期内实时测定了海水碳酸盐化学特征及其对应的原位血淋巴酸碱响应，证实潮间带贻贝在暴露阶段会每日出现酸化应激。利用这些野外数据为实验研究设定参数后，我们证实气温与贻贝体型对该酸化应激存在显著影响：在更高温度下，体型更大的贻贝会经历更为严重的酸化应激。此前在OA条件（pHNBS 7.7/pCO₂ 930 µatm）下的预浸没过程存在微弱的交互效应，使得暴露阶段初期测得的血淋巴pH值……