Seawater carbonate chemistry and energy status in the periwinkle Littorina littorea during experiments, 2011

In the future, marine organisms will face the challenge of coping with multiple environmental changes associated with increased levels of atmospheric Pco2, such as ocean warming and acidification. To predict how organisms may or may not meet these challenges, an in-depth understanding of the physiological and biochemical mechanisms underpinning organismal responses to climate change is needed. Here, we investigate the effects of elevated Pco2 and temperature on the whole-organism and cellular physiology of the periwinkle Littorina littorea. Metabolic rates (measured as respiration rates), adenylate energy nucleotide concentrations and indexes, and end-product metabolite concentrations were measured. Compared with values for control conditions, snails decreased their respiration rate by 31% in response to elevated Pco2 and by 15% in response to a combination of increased Pco2 and temperature. Decreased respiration rates were associated with metabolic reduction and an increase in end-product metabolites in acidified treatments, indicating an increased reliance on anaerobic metabolism. There was also an interactive effect of elevated Pco2 and temperature on total adenylate nucleotides, which was apparently compensated for by the maintenance of adenylate energy charge via AMP deaminase activity. Our findings suggest that marine intertidal organisms are likely to exhibit complex physiological responses to future environmental drivers, with likely negative effects on growth, population dynamics, and, ultimately, ecosystem processes.未来，海洋生物将面临应对与大气二氧化碳分压（Pco2）升高相关的多重环境变化的挑战，例如海洋变暖和酸化。为预测生物能否应对此类挑战，亟需深入解析生物响应气候变化的生理与生化调控机制。本研究针对滨螺（Littorina littorea）的整体生理及细胞生理，探究了升高的Pco2与温度的影响。本研究测定了代谢速率（以呼吸速率为表征指标）、腺苷酸能量核苷酸浓度与指数，以及终产物代谢物浓度。与对照组相比，滨螺在升高的Pco2条件下呼吸速率下降31%，在Pco2升高与温度升高的联合处理组中呼吸速率下降15%。酸化处理组中呼吸速率下降与代谢抑制及终产物代谢物浓度升高相关，表明生物对厌氧代谢的依赖程度上升。升高的Pco2与温度对总腺苷酸核苷酸含量亦存在交互效应，该效应显然可通过腺苷酸脱氨酶（AMP deaminase）活性维持腺苷酸能荷（adenylate energy charge）得到补偿。本研究结果表明，海洋潮间带生物对未来环境驱动因子可能呈现复杂的生理响应，这或将对生长、种群动态乃至最终的生态系统过程产生负面影响。