雅浦海沟沉积有机碳垂向分布及其指示意义  

Vertical distribution of sedimentary organic carbon in the Yap Trench and its implications

作　　者：吴彬 李栋[1,2] 赵军[1,2] 刘诚刚[1,2] 孙承君[3] 陈建芳[1,2] 潘建明[1,2] 韩正兵[1,2] 胡佶[1,2] WU Bin;LI Dong;ZHAO Jun;LIU Cheng-gang;SUN Cheng-jun;CHEN Jian-fang;PAN Jian-ming;HAN Zheng-Bing;HU Ji(Laboratory of Marine Ecosystem and Environment,Second Institute of Oceanography,State Oceanic Administration,Hangzhou 310012,China;Key laboratory of Marine Ecosystem and Biogeochemistry,State Oceanic Administration,Hangzhou 310012,China;Marine Ecology Center,First Institute of Oceanography,State Oceanic Administration,Qingdao 266237,China)

机构地区：[1]国家海洋局第二海洋研究所海洋生态与环境实验室,浙江杭州310012 [2]国家海洋局海洋生态系统与生物地球化学重点实验室,浙江杭州310012 [3]国家海洋局第一海洋研究所海洋生态中心,山东青岛266237

出　　处：《中国环境科学》2018年第9期3502-3511,共10页China Environmental Science

基　　金：国家自然科学基金青年科学基金项目(41606090);国家重点基础研究发展计划(973计划)项目(2015CB755904);国家海洋局第二海洋研究所基本科研业务费专项(JG1516)

摘　　要：利用蛟龙号载人深潜器采集了西太平洋雅浦海沟沉积柱样,分析了总有机碳(TOC)、δ^(13)C、粒度和比表面积(SSA)等参数,结合端元混合模型、降解模型及主成分分析(PCA),探讨不同来源有机碳(OC)垂向分布及其影响因素,估算了TOC降解速率、累积速率及通量.结果表明,雅浦海沟TOC%均值为(0.31%±0.10%),与浅海环境相当.由于外源OC主要赋存于粉砂等大粒径颗粒物以及微生物的分解作用,TOC%与粉砂%正相关,与SSA值及粘土比例负相关.微生物来源OC是TOC的主要贡献者(52%±21%),其次为海源(37%±19%)和陆源(11%±4%)OC,3种来源OC含量均随深度增加而降低.PCA结果指出,微生物来源与外源OC相对贡献间不耦合,表明海底地下水输送的OC可能是海沟微生物的重要营养源.主导沉积物中TOC垂向分布的难降解OC降解速率约为0.0012a^(-1),略高于普通大洋环境,但较浅海环境更低.雅浦海沟TOC累积速率为1.8×10^(-5)gC/(cm^2·a),沉降通量为2.2×10~9g C/a.Sediment core from the Yap Trench located in the west Pacific Ocean was collected by manned deep-sea research submersible Jiaolong.Geochemical parameter analyses(e.g.total organic carbon(TOC),δ13C,grain size composition and specific surface area(SSA)),combined with an end-member mixing model,a degradation model and principal component analysis(PCA)were conducted in order to 1)study the vertical distribution of the organic carbon(OC)and corresponding affecting factors,2)assess the degradation and accumulation rate and the flux of the sedimentary OC in the Yap Trench.The mean TOC content of the Yap Trench was(0.31%±0.10%)and was comparable with those of the neritic sediments.Probably due to enrichment of the allochthonous organic matter in the large grain-sized particles(e.g.silt)and intense decomposition of OC by microorganisms,the TOC content was positively related with silt%and negatively related with SSA and clay%.The microorganism-derived OC was the dominant proportion of the sedimentary TOC(52%±21%),followed by the marine(37%±19%)and terrestrial(11%±4%)OC.The OC contents of those three sources all decreased downward.Based on PCA,decoupling between the microorganism-derived and the allochthonous OC indicated that the OC delivered by the submarine groundwater was probably an important nutritional supply for the microorganisms in the trench.The degradation rate of the refractory OC which dominated the vertical profile of TOC was around 0.0012a-1,slightly higher than that of the normal deep ocean but lower than the neritic environment.The accumulation rate and settling flux of TOC in the Yap Trench were around 1.8×10-5gC/(cm2·a)and 2.2×109gC/a.

关 键 词：雅浦海沟 沉积有机碳 垂向分布 来源 降解 

分 类 号：X55[环境科学与工程—环境工程]