弱光层异养过程对海洋储碳的影响:进展、挑战和展望

Effects of heterotrophic processes in the twilight zone on oceanic carbon sequestration:advances,challenges and perspectives

海洋是地表系统最大的碳库和重要碳汇区。海洋生物泵通过一系列复杂的生物地球化学过程将CO_(2)转化成颗粒有机碳(Particulate Organic Carbon,POC)并输送到深海,是海洋储碳的重要途径。弱光层(真光层底部到1000 m)的生物异养过程消耗了超过70%从真光层输出的POC通量,决定了生物泵的储碳效率,因此准确定量弱光层的再矿化速率对评估海洋碳汇有重要意义。本文针对海洋生物泵储碳问题,聚焦弱光层异养过程对海洋储碳的影响机制,对全球弱光层再矿化定量工作进行评述,综合分析弱光层POC的衰减、再矿化等问题,并展望了相关新技术的应用。

Ocean is the largest carbon pool on Earth and has huge potential for the carbon sink.The biologically-mediated transfer of particulate organic carbon (POC) to the deep sea,aka oceanic biological carbon pump,is a key pathway for oceanic carbon sequestration.The heterotrophic processes in the twilight zone (typically defined as the depth between the bottom of the euphotic zone and 1 000 m) consume more than 70% of the POC exported from the euphotic zone,and determine the carbon sequestration efficiency of the biological carbon pump.Therefore,quantification of the remineralization rate in the twilight zone is essential for the ocean budget assessment.Aiming at the carbon storage problem of marine biological pump,this paper focuses on the influence mechanism of heterotrophic processes in the twilight zone on marine carbon storage,reviews the global studies for remineralization rate estimation in the twilight zone,comprehensively analyzes the attenuation and remineralization of POC in the twilight zone,and looks forward to the application of relevant novel technologies.