【摘要】 于2004年10月采集南黄海4个站位的柱状沉积物和29个站位的表层沉积物,用氧化浸取分光光度法研究了自然粒度下沉积物中的氮、磷分布特征以及控制其分布的生物地球化学机制。结果表明,多数站位随着沉积深度的增加,沉积物中氮、磷浓度趋于稳定。4个站稳定时氮浓度平均约为289μg/g,磷约为329μg/g,平均稳定浓度出现的沉积层次分别为氮>30cm,磷>22cm。氮、磷垂直分布形状的规则性与沉积速率密切相关,沉积速率越小的站位,其氮、磷垂直分布愈规则;海洋沉积物中的氮主要来源自海洋生物的代谢,而磷与陆源碎屑输入密切相关。氮与沉积物粘土含量、浮游动物生物量干重有明显的正相关关系。海水中浮游动物干重每增加1mg/m3,则沉积物中氮浓度增加5.64μmol/g,磷不存在这样的关系。沉积物中氮的早期成岩速率远高于磷,在沉积物海水界面附近氮约为磷的7.4倍。海水浮游生物生物量与沉积物中氮的早期成岩类型密切相关,在所研究的2004年秋季海水中,浮游动物生物量干重19mg/m3是沉积物中氮早期成岩类型转变的界限值,小于这一界限值,水体中的氮趋向于向沉积物中凝聚;大于19mg/m3,则沉积物中的氮趋向于向水体释放。更多还原

【Abstract】 The distributions of nitrogen(N)and phosphorus(P)in sediment cores in the south Yellow Sea(SYS)were studied in detail in this paper.The core sediments from 4 stations and surface sediments from 29 stations were collected in SYS in October 2004.The peak concentrations of N and P in the sediments,occurred in depth of 5—35cm,and the phosphorus peak was close to the sediment-seawater interface.The concentrations gradually approach to constants with the depth increasing.The average constant concentrations were 289 and 329μg/g for N and P in depth of >30cm and >22cm,respectively.The vertical patterns of N and P distribution were closely related to the sedimentation rate in a regular pattern at the stations with low sedimentation rate.The N content in sediment was mainly from the metabolism of marine organisms,while that of P was mainly from input of terrestrial detritus.The ratio of N/P was controlled by N distribution in the sediments of SYS.A clear positive correlation has been revealed among N concentration,clay amount in the sediment and dry weight of zooplankton biomass.For every 1mg/m3 increased in dry weight,the N concentration would add 5.64μmol/g up;however,no such relation has been found for P.Early diagenesis rate of N was much higher than that of P, e.g.the rate of N was 7.4 times greater than that of P in sediments.The critical value of early diagenesis for N was 19mg/m3 calculated from the data of autumn 2004.In other words,below the value,N in seawater would incline to accumulate in sediments;while above the threshold,N would be released from sediment to seawater.更多还原