Physiological Effects of carbon dioxide on marine invertebrates

大气中CO_2浓度的增加使整个浅海酸化，从而使所有海洋生物生活在日益酸性化的环境中。本文研究了海水CO_2浓度升高对太平洋白虾（Palaemon pacificus）的长期影响。在含1,000 ppmv和1,900 ppmv（百万分之一体积）CO_2（大气CO_2浓度预计在2100年和2300年左右）的海水中分别饲养30周和15周，以研究其对对虾存活、生长、摄食、蜕皮和繁殖的影响。与相应的对照组相比，两个CO_2组的存活率均受到显著抑制（1，000 ppmv组的最终存活率为55%，对照组为95% ; 1，900 ppmv组为65%，对照组为95%）。与对照组相比，1，900 ppmv组虾的生长显著受抑制，但摄食未受影响。相比之下，生长和喂养都不受30周暴露于1，000 ppmv的影响，而蜕皮在18周后比对照组明显更频繁。此外，1,000 ppmv组的5只雌性中只有1只产卵一次，而所有对照雌性（n=6）的产卵量为1至3倍。研究结果表明，未来海水CO_2浓度的升高可能会对对虾的死亡率、生长和繁殖产生负面影响，从而导致对虾种群数量减少。如果其他甲壳类动物也受到类似影响，未来的海洋生态系统可能会因改变海洋食物网的基本组成部分而发生巨大变化。

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.