黄河三角洲北部悬浮体和颗粒有机碳的分布与影响因素

2008年12月对黄河三角洲北部及其毗邻海域悬浮体浓度(SSC)和颗粒有机碳(POC)进行了研究,并结合该海域水文资料,分析了该区冬季SSC和POC的空间分布特征和影响因素.结果表明,冬季研究区水体中的SSC变化范围较大(5~1064mg/L),表、底层的SSC高值区(>600mg/L)均呈条带状分布于废弃神仙沟-钓口三角洲附近海域,且随水深加大SSC快速降低(400μg/L)集中于近岸海域,渤海中部POC仅为20~50μg/L左右,但底层POC向渤海湾中部扩散范围比表层大.POC和SSC之间存在显著正相关关系,表明该海区近岸浅水区沉积物再悬浮是影响研究区POC空间分布的重要原因.冬季SSC和POC高值区与最大侵蚀区、波致底切应力>0.2N/m2的区域相对应,表明在冬季强海洋动力条件下,废弃神仙沟-钓口三角洲叶瓣前缘不仅是沉积物的“源”,也同样是颗粒有机碳的“源”.

Distribution of suspended sediment and particulate organic carbon of the northern Huanghe Delta in winter in China

In Dec.2008,a total of 137 samples were collected from 34 stations off the northern Huanghe Delta to analyze the suspended sediment concentration(SSC) and particulate organic carbon(POC).The results show that the SSC varied between 5～1064mg/L,both the surface and bottom high SSC zone(>600mg/L) located parallel to the coastline along the delta coast of the abandoned Diaokou-Shenxiangou river mouth.The SSC decreased dramatically seaward with increasing water depth.The POC ranged from 17 to 640mg/L,with similar distribution pattern in surface and bottom layers.The high POC zone also located along the delta coast,however,this zone extended even further in the bottom layer,from the Diaokou mouth area to the central Bohai Bay.A significant positive correlation existed between POC and SSC,suggesting that the source of suspended sediments was an important factor for the POC.In winter,the high zones of SSC and POC were correlated well with the erosion center and the high wave-induced bottom shear stress(>0.2N/m2) off the abandoned Diaokou river mouth.This study suggests that the delta coast areas off the abandoned Diaokou-Shenxiangou river mouth were not only the major source of SSC,but also the POC,most likely caused by the strongly winter storm waves.