台湾海峡西部沉积物中碳的来源及埋藏

Sources,burial fluxes of Carbon in sediments of the western Taiwan Strait

根据2005年夏季航次观测的沉积物中总有机碳(TOC)、无机碳(CaCO3)、总氮(TN)、悬浮体颗粒有机碳(POC)、沉积物粒度数据得出,台湾海峡西部表层沉积物TOC质量分数的范围为0.01～1.79,平均值为0.37±0.24,略高于20多年前台湾海峡南部海区,而低于台湾海峡中、北部海区;TOC的质量分数湾内比湾外高,近岸比远岸高,且由北向南呈斑状分布的特征。CaCO3质量分数变化于0.11～23.00之间,其质量分数呈明显斑状分布,高值区主要分布在湾外的海域。表层沉积物C/N比值范围为6.70～27.54,平均值为10.12,表明有机质来源的混合性。TOC与TN间的本底关系极为密切。表层沉积物中TOC与粒径大小呈显著的幂数关系,粒径的差异对TOC的含量影响明显,而粒级不是CaCO3含量分布的制约因子。台湾海峡南部上升流区及附近海域沉积物TOC与上层初级生产力分布并不耦合。台湾海峡西部每年埋藏于沉积物中的碳的通量为105tC。河流陆源输入、北向的沿岸流、南澳-东山外上升流以及平潭岛附近上升流对沉积物中碳的埋藏有重要影响。

Total organic carbon（TOC）,CaCO3,total nitrogen（TN）,particulate organic carbon（POC） and grain size in surface sediments of the western Taiwan Strait were analysed in 2005.TOC and CaCO3 contents varied in the ranges of 0.01～1.79 and 0.11～23.00 respectively.The average content of TOC in the surface sediments was 0.37±0.24 which larger than the TOC in the Southern Taiwan Strait,but smaller than the TOC in the center and north of Taiwan Strait in 1980s.High level of TOC content was found near-shore and decreased seaward.Region with high and low value of CaCO3 had the scattering features.The average ratio C/N which indicated the mixed sources of organic materials was 10.12.The background relationship between TOC and TN was close.The power correlation between OC and grain size was suggested that grain size was a limiting factor for TOC.But there was not a good relation between grain size and CaCO3.TOC in sediment was not coupled with primary production in water in or around the upwelling area of the southern Taiwan Straint.After calculation,burial fluxes of carbon was 105 t/a in the sediments of the western Taiwan Strait.The terrestrial input,coastal current and upwelling significantly influenced the burial fluxes of carbon in the sediment.