两种大型经济海藻响应CO2升高与温度变化的光合生理机制

Marine macroalgae, being as primary producers, played a critical ecological role in coastal carbon cycle. The global warming proceed was accompanied by elevated atmospheric CO2. Ocean acidification (OA) was finally induced as well as the continuous rise of sea surface temperature. These significant changes obviously affected the ecological conditions of macroalgae growth and cultivation. This proposal selected cultivated economic seaweed species in southern China, Pyropia haitanensis and Gracilariopsis lemaneiformis, as the experimental materials. The selected species were cultured both at indoor- and outdoor-controlled conditions. Then the mechanistic responses of growth, photosynthetic carbon acquisitions, nitrogen assimilation, biochemical components and quality characteristics of algae to elevated CO2, temperature change and their synergistic effects were extensively investigated. Simultaneously, the function of CO2 reduction related with seaweed cultivation would be quantitative analyzed under the background of global warming. Therefore, this proposal provided the scientific basis for the possible effect on macroalgae physiological functions, yields and quality characteristics. Furthermore, the theoretical and technical supports were supplied for algae in response to the global climate change.

大型海藻作为主要初级生产者，在近岸海域碳循环中起着非常重要的生态作用。全球暖化与大气CO2浓度升高相伴而生，直接后果是引起海水酸化和海洋表层温度升高。这些气候变化显著影响海藻生长和栽培的环境生态条件。本项目选择我国南方海域主要栽培经济海藻——坛紫菜和龙须菜为研究对象，通过实验室内与室外受控培养相结合，探讨经济海藻生长与光合无机碳利用、氮吸收同化、生化组分及品质性状对CO2浓度升高、温度变化耦合作用的响应机制；同时，定量分析在全球变暖背景下栽培经济海藻在CO2生物削减方面的作用，为栽培海藻重要生命过程的变动、及其对产量与品质特征的可能影响提供科学依据，并为近岸海藻栽培实践提供重要理论和技术支撑。

随着工业化进程加快、森林植被破坏及化石燃料过度燃烧等原因，大气中CO2浓度呈现出持续快速增长的趋势。海洋作为碳汇能够吸收大气中的CO2，维持海水中碳酸盐系统的新平衡。大型经济海藻在我国南方近岸海域大量种植，是海洋生态系统中重要的初级生产者，在削减大气CO2浓度及减缓全球变暖方面发挥着重要作用。随着近岸海域富营养化等环境问题的相继出现，关于近海栽培经济海藻的CO2利用与其它重要环境因素相互耦合的生命功能变动的生理机制研究还鲜有报道。针对上述各种环境因素耦合效应的生命功能变动机制，本项目主要对两种大型经济海藻（龙须菜和坛紫菜）如何响应大气CO2升高与温度变化的光合生理机制展开研究。在研究过程中，详细分析龙须菜和坛紫菜的生长、光合放氧速率、暗呼吸速率、抗氧化酶活性及生化组分特征等的变化，阐述了两种海藻应对大气CO2升高和温度变化或其它环境因子变化的生理生态学响应机制。目前该项目已发表论文5篇。本项目所取得的成果对于阐释重要栽培经济海藻光合作用及相关重要代谢过程对气候变化的响应机制，定量评估我国海藻栽培业在大气CO2生物削减及减缓全球气候暖化方面的贡献提供科学依据。