Seawater carbonate chemistry and biological processes of Pandalus borealis during experiments, 2011

Ocean acidification (OA) resulting from anthropogenic emissions of carbon dioxide (CO2) has already lowered and is predicted to further lower surface ocean pH. There is a particular need to study effects of OA on organisms living in cold-water environments due to the higher solubility of CO2 at lower temperatures. Mussel larvae (Mytilus edulis) and shrimp larvae (Pandalus borealis) were kept under an ocean acidification scenario predicted for the year 2100 (pH 7.6) and compared against identical batches of organisms held under the current oceanic pH of 8.1, which acted as a control. The temperature was held at a constant 10°C in the mussel experiment and at 5°C in the shrimp experiment. There was no marked effect on fertilization success, development time, or abnormality to the D-shell stage, or on feeding of mussel larvae in the low-pH (pH 7.6) treatment. Mytilus edulis larvae were still able to develop a shell in seawater undersaturated with respect to aragonite (a mineral form of CaCO3), but the size of low-pH larvae was significantly smaller than in the control. After 2 mo of exposure the mussels were 28% smaller in the pH 7.6 treatment than in the control. The experiment with Pandalus borealis larvae ran from 1 through 35 days post hatch. Survival of shrimp larvae was not reduced after 5 wk of exposure to pH 7.6, but a significant delay in zoeal progression (development time) was observed.由人为二氧化碳（CO₂）排放引发的海洋酸化（OA）已经导致表层海水pH值下降，且预计未来还将进一步降低。由于二氧化碳在低温环境下溶解度更高，因此亟需研究海洋酸化对冷水环境生物的影响。本实验选取紫贻贝（Mytilus edulis）幼体以及北方长额虾（Pandalus borealis）幼体作为研究对象，将其置于预测为2100年的海洋酸化场景（pH 7.6）中培养，并以维持在当前海洋pH值8.1的同批次生物作为对照组。紫贻贝实验的培养温度恒定为10℃，虾类实验的培养温度则恒定为5℃。在低pH（pH 7.6）处理组中，紫贻贝幼体的受精成功率、发育时长、D形幼虫期畸形率以及摄食情况均未受到显著影响。尽管实验海水对于文石（aragonite，CaCO₃的一种矿物形态）处于不饱和状态，但紫贻贝幼体仍可形成贝壳，但低pH处理组幼体的体型显著小于对照组。暴露培养2个月后，pH 7.6处理组的紫贻贝体型较对照组小28%。北方长额虾幼体实验的培养周期为孵化后1至35天。在pH 7.6环境中暴露5周后，虾类幼体的存活率未出现下降，但观察到其溞状幼体发育进程（发育时长）出现显著延迟。