National Key Research and Development Program, 2016-2021, Leading PI: Yao Zhang
课题1 中涉及的输出埋藏到沉积物的颗粒有机碳，课题1 和2 同时涉及的不易降解的惰性溶解有机碳分子，以及课题2 中涉及的人为活动、陆源输入，将通过课题3的沉积记录（生物标记物和碳、氢同位素），重建地史过程中的海洋碳汇演变，从而古今链接研究近海碳库变动与过去历史上全球变化事件的关系。
Ocean is the largest carbon pool on earth, serving as the buffer of global climate change, absorbing about 1/3 of CO2 produced by human activities. Carbon sink captured by marine ecosystem is called the "Blue Carbon Sink" (hereinafter referred to as "blue carbon"), which is one of the most important mechanisms for the sea to store carbon. The initial form of blue carbon is visible plant carbon sequestration in the coastal zone. As a matter of fact, the invisible microorganisms (phytoplankton, bacteria, archaea, and protozoa), which have always been ignored, account for 90% of the marine biomass and constitute the main component of blue carbon. The marginal sea covers one third of the total territory of China, and it is of urgent need to explore the immense potential of carbon sinks. This project aims at the key processes and mechanisms of the carbon sequestration in coastal ecosystems and ways to increase ocean carbon sink.
An increasing carbon sink, on the one hand, refers to increasing the sinking and burial of particle organic carbon (POC) in sediments; and on the other hand, it is about increasing the production of refractory dissolved organic carbon (RDOC) mediated by microorganisms (the overall amount of the RDOC pool is equal to that of CO2 in the atmosphere). This project is comprised of four subprojects.
Subproject 1 (PI: Yao Zhang, Xiamen University) focuses on community structure and ecosystem function in the carbon cycle, with an emphasis on key processes concerning the POC sinking and the RDOC production.
Subproject 2 (PI: Qiu Cui, Qingdao Institute of Bioenergy and Bioprocess Technology, CAS) focuses on physiological and molecular mechanisms of ocean carbon sinks, such as uptake, transformation, and release of carbon-containing chemical compounds by microorganism at the gene and protein levels. This subproject also focuses the impact of human activities and input of terrestrial nitrogen and phosphorus on the above processes.
Subproject 3 (PI: Meixun Zhao, Ocean University of China) focuses at re-establishing the evolution process of ocean carbon sinks in geologic history with sedimentary records, which should record organic carbon from burial of sinking POC in sediments studied in subject 1, the RDOC molecules studied in both subproject 1 and 2, and the human activities and input of terrestrial sources studied in subproject 2, and aims at the relationship between ocean carbon sinks and global climate changes in ancient oceans.
Based on field investigation, theoretical analysis and historical representation of the subproject 1, 2, and 3, subproject 4 (PI: Jiaguo Qi, Zhejiang University) aims at establishing scenario models for carbon sink dynamics under global warming situation, and providing theoretical and technical foundations for engineering ocean carbon sequestration in the future.
This project is featured in its interdisciplinary cooperation and integration. Potential breakthroughs are especially expected in the following aspects: (1) key processes and regulatory mechanisms of ocean carbon sink and its relationship with environment and global climate changes; (2) an index system for carbon storage including a series of physical-chemical and biological indices and parameters and main core measurements protocols; (3) demonstrations of increasing carbon sink and engineering carbon sequestration in the ocean. These outputs will support the sustainable development of marine ecosystem and national carbon emissions trading.