Collaborative Research: Ocean Acidification-Category 1: Effects of pCO2 and pH on Photosynthesis, Respiration and Growth in Marine Phytoplankton

大约三分之一的二氧化碳排放溶解在海洋表面沃茨中，增加了海水的酸度（海洋酸化现象）。海水酸化的生物影响之一是浮游植物生长的变化，而浮游植物是海洋食物网的基础。然而，据报告，二氧化碳浓度增加对浮游植物生长的影响各不相同，包括增加、无影响或减少。该项目的目标是了解海洋浮游植物对二氧化碳浓度和酸度增加的生理反应。这些知识将使人们有可能评估并最终预测浮游植物生态和海洋生产力的未来变化。有待检验的假设是，二氧化碳的增加和酸度的增加（pH值的下降）都会影响海洋浮游植物的生长。假设1）二氧化碳水平升高将导致更高的光合效率，2）海水pH值较低将减少浮游植物必须花费以维持其正常内部pH值的能量。将进行实验以测试浮游植物物种之间光合和呼吸生理的差异是否会导致对二氧化碳浓度和海洋酸度的不同反应。这些假设将在实验室实验和补充实地研究中进行测试，使用质谱技术和分子标记分析来追踪碳和氧代谢。在新泽西沿海沃茨、百慕大群岛和加州附近的铁限制沃茨进行自然浮游植物的现场实验。更广泛的影响这个项目解决了社会上非常关注的问题，将为本科生提供研究经验，并为研究生和博士后研究员提供培训。来自当地大专院校的暑期实习生将参与该项目。 将为初中和高中学生和教师编制一套关于气候变化和海洋酸化的问题导向学习材料。主要调查人员将与气候中心合作，这是一个非营利组织，为网络，电视台和其他向公众提供信息的媒体内容做准备。

Approximately one third of carbon dioxide emissions dissolve in the surface waters of the ocean and increase its acidity (the phenomenon of ocean acidification). Amongst the biological effects of seawater acidification are changes in the growth of phytoplankton, organisms that are the basis for marine food-webs. However, variable effects on phytoplankton growth of increasing carbon dioxide concentration have been reported, including an increase, no effect or a decrease. The objective of this project is to understand the physiological response of marine phytoplankton to increasing concentrations of carbon dioxide and acidity. This knowledge will make it possible to assess, and eventually predict, future changes in phytoplankton ecology and ocean productivity. The hypothesis to be tested is that the increase in carbon dioxide and the increase in acidity (a decrease in pH) both influence the growth of marine phytoplankton. It is postulated 1) that elevated carbon dioxide levels will lead to a higher photosynthetic efficiency, and 2) that a lower pH of seawater will decrease the energy that phytoplankton must spend to maintain their normal internal pH. Experiments will be carried out to test if differences in photosynthetic and respiratory physiology between phytoplankton species will result in different responses to carbon dioxide concentration and ocean acidity. These hypotheses will be tested in laboratory experiments and complementary field studies, using mass spectrometric techniques and the analysis of molecular markers to trace carbon and oxygen metabolism. Field experiments with natural phytoplankton will be carried out in New Jersey coastal waters, Bermuda, and iron-limited waters off California.Broader ImpactsThis project, which addresses an issue of significant concern to society, will provide research experiences for undergraduates and training for graduate students and a postdoctoral fellow. Summer interns from local junior colleges will participate in the project. A problem-based learning package on climate change and ocean acidification targeting middle and high school students and teachers will be developed. The principal investigators will work with Climate Central, a nonprofit organization that prepares media content for the web, television stations and other outlets that provide information to the public.