Southern California Coastal Water Research Project, Costa Mesa, California 92626, United States.
National Institute of Biology, Marine Biological Station, 6330 Piran, Slovenia.
Environ Sci Technol. 2022 Jun 21;56(12):9015-9028. doi: 10.1021/acs.est.2c00010. Epub 2022 May 11.
Coastal-estuarine habitats are rapidly changing due to global climate change, with impacts influenced by the variability of carbonate chemistry conditions. However, our understanding of the responses of ecologically and economically important calcifiers to pH variability and temporal variation is limited, particularly with respect to shell-building processes. We investigated the mechanisms driving biomineralogical and physiological responses in juveniles of introduced (Pacific; ) and native (Olympia; ) oysters under flow-through experimental conditions over a six-week period that simulate current and future conditions: static control and low pH (8.0 and 7.7); low pH with fluctuating (24-h) amplitude (7.7 ± 0.2 and 7.7 ± 0.5); and high-frequency (12-h) fluctuating (8.0 ± 0.2) treatment. The oysters showed physiological tolerance in vital processes, including calcification, respiration, clearance, and survival. However, shell dissolution significantly increased with larger amplitudes of pH variability compared to static pH conditions, attributable to the longer cumulative exposure to lower pH conditions, with the dissolution threshold of pH 7.7 with 0.2 amplitude. Moreover, the high-frequency treatment triggered significantly greater dissolution, likely because of the oyster's inability to respond to the unpredictable frequency of variations. The experimental findings were extrapolated to provide context for conditions existing in several Pacific coastal estuaries, with time series analyses demonstrating unique signatures of pH predictability and variability in these habitats, indicating potentially benefiting effects on fitness in these habitats. These implications are crucial for evaluating the suitability of coastal habitats for aquaculture, adaptation, and carbon dioxide removal strategies.
由于全球气候变化，沿海-河口生境正在迅速变化，其影响受到碳酸盐化学条件可变性的影响。然而，我们对生态和经济上重要的钙化生物对 pH 值变化和时间变化的响应的理解是有限的，特别是在贝壳形成过程方面。我们在为期六周的流动实验条件下，研究了在引入（太平洋；）和本地（奥林匹亚；）牡蛎幼体中驱动生物矿化和生理响应的机制，这些实验条件模拟了当前和未来的条件：静态对照和低 pH（8.0 和 7.7）；低 pH 与波动（24 小时）幅度（7.7 ± 0.2 和 7.7 ± 0.5）；以及高频（12 小时）波动（8.0 ± 0.2）处理。牡蛎在包括钙化、呼吸、清除和生存在内的重要过程中表现出生理耐受性。然而，与静态 pH 条件相比，贝壳溶解显著增加，这是由于更长时间暴露于较低 pH 条件下的累积效应，其溶解阈值为 pH7.7 时的 0.2 幅度。此外，高频处理引发了更大的溶解，可能是因为牡蛎无法应对变化的不可预测频率。实验结果被推断为几个太平洋沿海河口存在条件的背景，时间序列分析表明这些生境中 pH 可预测性和变异性具有独特特征，表明这些生境可能对适应和二氧化碳去除策略具有潜在的益处。这些影响对于评估沿海生境对水产养殖、适应和二氧化碳去除策略的适宜性至关重要。
