胡利民, 石学法, 刘焱光, 白亚之, 董林森, 黄元辉. 白令海西部柱样沉积物中有机碳的地球化学特征与埋藏记录[J]. 海洋地质与第四纪地质, 2015, 35(3): 37-47. DOI: 10.3724/SP.J.1140.2015.03037
引用本文: 胡利民, 石学法, 刘焱光, 白亚之, 董林森, 黄元辉. 白令海西部柱样沉积物中有机碳的地球化学特征与埋藏记录[J]. 海洋地质与第四纪地质, 2015, 35(3): 37-47. DOI: 10.3724/SP.J.1140.2015.03037
HU Limin, SHI Xuefa, LIU Yanguang, BAI Yazhi, DONG Linsen, HUANG Yuanhui. GEOCHEMICAL CHARACTERISTICS AND BURIAL RECORDS OF ORGANIC CARBON IN THE COLUMN SEDIMENTS FROM WESTERN BERING SEA[J]. Marine Geology & Quaternary Geology, 2015, 35(3): 37-47. DOI: 10.3724/SP.J.1140.2015.03037
Citation: HU Limin, SHI Xuefa, LIU Yanguang, BAI Yazhi, DONG Linsen, HUANG Yuanhui. GEOCHEMICAL CHARACTERISTICS AND BURIAL RECORDS OF ORGANIC CARBON IN THE COLUMN SEDIMENTS FROM WESTERN BERING SEA[J]. Marine Geology & Quaternary Geology, 2015, 35(3): 37-47. DOI: 10.3724/SP.J.1140.2015.03037

白令海西部柱样沉积物中有机碳的地球化学特征与埋藏记录

GEOCHEMICAL CHARACTERISTICS AND BURIAL RECORDS OF ORGANIC CARBON IN THE COLUMN SEDIMENTS FROM WESTERN BERING SEA

  • 摘要: 基于2012年中国第5次北极科学考察专项调查获得的样品资料,重点探讨了百年来白令海西部柱样沉积物中有机碳(TOC)的地球化学特征及其埋藏记录,结果显示,基于两柱样210Pbex随深度的指数衰变趋势,整体能反映出调查区相对稳定的现代沉积环境,可获得两沉积柱约70年以来的海洋沉积环境序列。陆架区BL16柱样中TOC的垂向分布与TN及粒度具有较好的一致性,反映出有机质来源较为一致,粒度可能对沉积有机碳的赋存起控制作用;而陆坡区BL10柱样粒度相对略粗,且TOC与TN、粒度无明显相关关系,这可能与该区复杂的沉积水动力环境、有机质输入和较强的细菌微生物作用有关。两柱样上层样品(近20年以来)都不同程度表现出TOC含量增加和CaCO3含量下降,这可能指示了近期北极地区变暖和海洋酸化加剧等过程对沉积有机质的影响。计算得到两柱样沉积有机碳的埋藏通量分别为3 100 mmol C·m-2·a-1(BL16)和1 400 mmol C·m-2·a-1(BL10),通过对有机碳埋藏保存效率的分析和区域对比,认为该区较高的有机碳埋藏通量,可能主要受控于较高的上层水体初级生产力和有机碳输出效率,较为有利的沉积有机碳保存代谢机制以及较快的沉积速率等因素的共同作用。

     

    Abstract: Using the two column samples (BL16 and BL10) taken during the Fifth Chinese National Arctic Expedition Cruise at the western Bering Sea, the geochemical characteristics and burial records of total organic carbon (TOC) over the past century were studied. The results show that the depositional regime was rather stable in the study area according to the vertical distribution of 210Pb profiles and its relationship to the core depth. Therefore, the sedimentary record of the past seventy years could be established for the two short cores respectively. As in the core BL16, there is a good correlation between TOC and total nitrogen (TN) as well as grain sizes, suggesting a consistent provenance of sedimentary organic components and the control of sediment grain size over the OM burial. On the other hand, the core BL10 from the upper slope was composed of more coarser sediments where exist poor relation between TOC and TN, probably caused by the complex depositional regime, varying OM input and microorganism activity. A clear shift of TOC and CaCO3 abundance in the upper sections (about twenty years ago) were observed in both two cores, which may indicate the recent regional warming in the arctic area and ocean acidification. The TOC sequestration in the two cores were estimated as 3100 mmol C·m-2·a-1 and 1400 mmol C·m-2·a-1, respectively. After the examination of the preservation of sedimentary TOC and the regional correlation of TOC sink fluxes, the relatively higher sequestration of TOC in the study area could be constrained by the higher marine productivity, quick POC export from the upper water column, effective metabolic processing and higher sedimentation rates of the seabed.

     

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