中国近海沉积物在生源要素循环中的功能

中国近海沉积物中生源要素的含量与其粒度、河流输入等诸多因素有关。一般沉积物粒度由粗到细 ,有机质含量由低到高 ,OC ,N ,P的含量递增 ,S和Si含量递减。沉积物的生物地球化学环境涉及到Eh ,pH ,温度 ,OC含量 ,Fe3 /Fe2 值 ,水动力条件 ,沉积物的颗粒大小和间隙水的S体系 ,以及生物扰动等因素 ,它们影响着沉积物中生源要素的早期成岩过程和循环。一般而言 ,中国近海沉积物—海水界面S2 -,HS-,H4SiO4,PO43 -,NH4 的扩散通量是从沉积物向上覆水 ,而SO42 -,HCO3 -,NO3 -,NO2 -的扩散通量从上覆水向沉积物中扩散。生物扰动对沉积物—海水界面生源要素的循环起重要作用。

Functions of China marginal sea sediments in the cyclesof biog enic elements

The contents of biogenic elements in China marginal sea sediments are related to their grain sizes, river transport, et al . In general, the finer the grain size has, the higher the contents of organic matter and OC, N, P and the lower the contents of S and Si. The biogeochemical environments of sediments are related with E h, pH, alkali degree, content of OC, Fe 3 /Fe 2 radio, water dynamics condition, grain size of sediment, S system in sediment interstitial waters, et al ., and they influence the early diageneses and cycles of biogenic elements in sediments. In most regions of China marginal sea, the flux directions of S 2- , HS -, H 4SiO 4, PO 4 3- , NH 4 across sediment water interface are from sediment to overlying seawater, the flux directions of SO 4 2- , HCO 3 -, NO 3 -, NO 2 - across sediment water interface are from overlying seawater to sediment. The irrigation of living things is important in the cycles of the biogenic elements across sediment water interfaces.