Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, USA.
Ann Rev Mar Sci. 2009;1:169-92. doi: 10.1146/annurev.marine.010908.163834.
Rising atmospheric carbon dioxide (CO2), primarily from human fossil fuel combustion, reduces ocean pH and causes wholesale shifts in seawater carbonate chemistry. The process of ocean acidification is well documented in field data, and the rate will accelerate over this century unless future CO2 emissions are curbed dramatically. Acidification alters seawater chemical speciation and biogeochemical cycles of many elements and compounds. One well-known effect is the lowering of calcium carbonate saturation states, which impacts shell-forming marine organisms from plankton to benthic molluscs, echinoderms, and corals. Many calcifying species exhibit reduced calcification and growth rates in laboratory experiments under high-CO2 conditions. Ocean acidification also causes an increase in carbon fixation rates in some photosynthetic organisms (both calcifying and noncalcifying). The potential for marine organisms to adapt to increasing CO2 and broader implications for ocean ecosystems are not well known; both are high priorities for future research. Although ocean pH has varied in the geological past, paleo-events may be only imperfect analogs to current conditions.
大气中二氧化碳（CO2）浓度不断升高主要是由于人类燃烧化石燃料所致，这降低了海水 pH 值，并导致海水碳酸盐化学发生大规模变化。海洋酸化这一过程在实地数据中有充分记录，如果未来不大幅减少二氧化碳排放，这一过程在本世纪内还将加速。酸化改变了海水化学形态和许多元素及化合物的生物地球化学循环。一个众所周知的影响是降低了碳酸钙饱和度，这影响了从浮游生物到底栖软体动物、棘皮动物和珊瑚等多种形成贝壳的海洋生物。在高二氧化碳条件下的实验室实验中，许多钙化物种的钙化和生长速度都有所下降。海洋酸化还导致一些光合作用生物（包括钙化和非钙化生物）的碳固定率增加。海洋生物适应不断增加的二氧化碳的潜力以及对海洋生态系统的更广泛影响尚不清楚；这些都是未来研究的重点。尽管海洋 pH 值在地质历史上有所波动，但古事件可能只是当前情况的不完美模拟。
