黄河不同粒径悬浮物中POC含量及输运特征研究

POC Content in Size-Fractioned TSS and Transportation Character in The Yellow River

悬浮物(TSS)粒径与颗粒有机碳(POC)含量关系的研究,是河流POC形态变化及输送过程和输运通量研究的基础.本研究在沉降分级法基础上,结合激光粒度仪粒度测定和多元线性回归分析的数据处理方法,对2005-06-29黄河利津站、2005-09-27黄河口低盐度区以及2006年11月兰州、潼关、花园口各站TSS样品分析发现:黄河TSS中POC与其对应的中值粒径存在良好的负指数关系,POC的极限值为0.56%,普遍低于世界其它河流;黄河不同区段站位TSS性质不同使各样品相同粒级间POC存在明显的差异,黄河口站>花园口站>兰州站>潼关站>利津站,如<8μm粒级TSS中POC依次是0.661%、0.627%、0.550%、0.505%、0.493%;黄河各粒级TSS所承载的POC量占样品POC总量的比例在不同区段各样品间极其相近,POC随TSS粒径增大显著递减,80%以上的POC集中在<16μm的TSS中,而粒径<32μm的TSS承载了95%以上的POC.可见虽然黄河自西向东横跨5000km之多,落差达4000m以上,但POC的输运规律具有一致性,TSS粒径是控制POC输运特性的主要因素.

Relationship between grain size of total suspended solids （TSS） and particulate organic carbon （POC） content is the base of studying POC transportation and flux in river. Based on sedimentation classification, POC in size-fractioned TSS of The Yellow River was studied by multiple linear regression. The results indicate that： with the median diameter increasing, POC is decreased in a logarithm tendency, the maximum is 0.56% lower than the other rivers; POC is different in the same size-fractioned TSS between characteristic sample stations： the estuary 〉 Huayuankou 〉 Lanzhou 〉 Tongguan 〉 Lijin, for example POC is 0.661%, 0.627 %, 0.550 %, 0.505 %, 0.493 % in TSS of which the grain size is 〈 8 p.m; the proportion of POC in size-fraetioned TSS has little distinction, POC is decreased remarkably with the increasing of the grain size of TSS, and more than 80% of POC is concentrated in the particles 〈 16 p.m while over 95% of POC is concentrated in particles of size 〈 32 μm. So the transportation of POC is consistent, the main control of transportation of POC is attributed to the grain size of TSS.