Unveiling the secrets of diatom-mediated calcification:Implications for the biological pump  

作　　者：Yiwen PAN Yifan LI Chen-Tung Arthur CHEN Zong-Pei JIANG Wei-Jun CAI Yunwen SHEN Zesheng DING Qixian CHEN Yanan DI Wei FAN Chenba ZHU Ying CHEN 

机构地区：[1]Ocean College,Zhejiang University,Zhoushan 316021,China [2]Hainan Institute of Zhejiang University,Sanya 570203,China [3]Department of Oceanography,Sun Yat-Sen University,Gaoxiong 80424,China [4]School of Marine Science and Policy,University of Delaware,Newark DE 19716,USA [5]Carbon Neutral Innovation Research Center,Xiamen University,Xiamen 361005,China

出　　处：《Science China Earth Sciences》2024年第9期2895-2909,共15页中国科学（地球科学英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.42188102&42176036);the Zhejiang Provincial Natural Science Foundation of China(Grant No.LD24D060002);the Science and Technology Program of Zhoushan City(Grant No.2022C81002);the Fundamental Research Funds for the Central Universities,and the Ocean Negative Carbon Emission(ONCE)。

摘　　要：Siliceous diatoms are one of the most prominent actors in the oceans,and they account for approximately 40%of the primary production and particulate organic carbon export flux.It is believed that changes in carbon flux caused by variations in diatom distribution can lead to significant climate shifts.Although the fundamental pathways of diatom-driven carbon sequestration have long been established,there are no reports of CaCO_(3) precipitation induced by marine diatom species.This manuscript introduces novel details regarding the enhancement of aragonite precipitation during photosynthesis in Skeletonema costatum in both artificial and natural seawater.Through direct measurements of cell surfaces via a pH microelectrode and zeta potential analyzer,it was determined that the diatom-mediated promotion of CaCO_(3) precipitation is achieved through the creation of specific microenvironments with concentrated[CO_(3)^(2-)]and[Ca^(2+)]and/or the dehydrating effect of adsorbed Ca^(2+).Based on this mechanism,it is highly plausible that diatom-mediated calcification could occur in the oceans,an assertion that was supported by the significant deviation of total alkalinity(TA)from the conservative TA-salinity mixing line during a Skeletonema costatum bloom in the East China Sea and other similar occurrences.The newly discovered calcification pathway establishes a link between particulate inorganic and organic carbon flux and thus helps in the reassessment of marine carbon export fluxes and CO_(2) sequestration efficiency.This discovery may have important ramifications for assessing marine carbon cycling and predicting the potential effects of future ocean acidification.

关 键 词：Diatom bloom Skeletonema costatum CALCIFICATION Biological carbon pump Counter carbonate pump 

分 类 号：Q948.8[生物学—植物学]