Physiological Effects of carbon dioxide on marine invertebrates

大气中二氧化碳(CO2)浓度的增加使整个浅海海洋酸化，从而迫使所有海洋生物生活在日益酸性的环境中。在本研究中，我们评估了海水CO_2浓度升高对太平洋对虾的长期影响。对虾在空气中含有1,000 ppmv和1,900 ppmv(预计在2100年和2300年左右出现的大气二氧化碳浓度)的平衡海水中饲养30周和15周，以研究对生存、生长、摄食、蜕皮和繁殖的影响。两个CO_2组的存活率均显著低于各自的对照组(1000ppmv组的最终存活率为55%，对照组为95%；1900ppmv组为65%，对照组为95%)。与对照相比，1900ppmv的对虾生长受到显著抑制，但摄食没有受到影响。相比之下，暴露在1000ppmv的30周内，无论是生长还是摄食都没有受到影响，而在18周后，蜕皮的频率明显高于对照组。此外，1000ppmv组的五只雌性中只有一只产卵一次，而所有对照雌性(n=6)的产卵量是对照组的1-3倍。目前的结果表明，预测的未来海水CO_2状况可能会通过对死亡、生长和繁殖产生负面影响来减少对虾数量。如果其他甲壳类动物受到类似的影响，未来的海洋生态系统可能会通过改变海洋食物网的基本成分而发生巨大变化。

The increasing atmospheric concentration of carbon dioxide (CO_2) has been acidifying the whole neritic ocean, thereby driving all marine organisms to live in increasingly acidic environments. In the present study, we evaluated the long-term effects of increased seawater CO_2 on the marine shrimp Palaemon pacificus. Shrimps were reared in seawater equilibrated with air containing 1,000 ppmv and 1,900 ppmv (parts per million by volume) CO_2, the atmospheric CO_2 concentration predicted to occur around the year 2100 and 2300, for 30 and 15 weeks, respectively, to investigate effects on survival, growth, feeding, moulting and reproduction. Survival was significantly suppressed in both CO_2 groups compared to the respective controls (the final survival of the 1,000 ppmv group 55%, control 95% ; 1,900 ppmv 65%, control 95%). Growth of the 1,900 ppmv shrimps was significantly depressed compared to the control although feeding was unaffected. In contrast, both growth and feeding were unaffected by the 30-week exposure to 1,000 ppmv, while moulting became significantly more frequent than in the control after 18 weeks. In addition, only one of the five females in the 1,000 ppmv group bore eggs once, compared with 1 to 3 times of egg production in all control females (n=6). The present results demonstrate that the predicted future seawater CO_2 conditions would possibly reduce shrimp population through negatively affecting mortality, growth, and reproduction. If other crustaceans are similarly affected, the future marine ecosystem may be drastically altered through changing the essential constituents of the marine food web.