Abstract Natural cycles in the seawater partial pressure of carbon dioxide (CO2) in the Gulf of Maine, which vary in surface waters from ~250 to 550 µatm seasonally, provide an opportunity to observe how the life cycle and phenology of the shelled pteropod Limacina retroversa responds to changing food, temperature and carbonate chemistry conditions. Distributional, hydrographic, and physiological sampling suggest that pteropod populations are located in the upper portion of the water column (0–150 m) with a maximum abundance above 50 m. Gene expression and shell condition measurements show that the population already experiences biomineralization stress in the winter months when measured aragonite saturation state was at a seasonal low (though slightly oversaturated), reinforcing the usefulness of this organism as a bio-indicator for pelagic ecosystem response to ocean acidification. There appear to be two reproductive events per year with one pulse timed to coincide with the spring bloom, the period with highest respiration rate, fluorescence, and pH, and a second more extended pulse in the late summer and fall when saturation states remain high and fluorescence begins to decline. During the fall there is transcriptomic evidence of lipid storage for overwintering, allowing the second generation to survive the period of low food and aragonite saturation state. Based on these observations we predict that in the future pteropods will likely be most vulnerable to changing CO2 regionally during the fall reproductive event when CO2 concentration already naturally rises and when there is the added stress of generating lipid stores.

中文翻译：

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与生命周期和碳酸盐化学相关的缅因湾翼足类 Limacina reversa 生理学和壳条件的季节性变化

摘要 缅因湾二氧化碳 (CO2) 海水分压的自然循环，在地表水中季节性变化从 ~250 到 550 µatm，为观察带壳翼足类动物 Limacina retroversa 的生命周期和物候学提供了机会对不断变化的食物、温度和碳酸盐化学条件做出反应。分布、水文和生理采样表明翼足类种群位于水体的上部（0-150 m），最大丰度超过 50 m。基因表达和壳条件测量表明，当测量的文石饱和状态处于季节性低点（尽管略微过饱和）时，该种群在冬季已经经历了生物矿化压力，加强这种生物作为远洋生态系统对海洋酸化反应的生物指标的有用性。每年似乎有两次繁殖事件，一次脉冲与春季开花相吻合，这是呼吸率、荧光和 pH 值最高的时期，第二次延长的脉冲发生在夏末和秋季，此时饱和状态仍然很高且荧光开始下降。在秋季，有转录组学证据表明脂质储存可用于越冬，使第二代能够在低食物和文石饱和状态期间存活下来。