胶州湾沉积物－海水界面硅的交换速率及其影响因素探讨

摘要

The benthic exchange rates of dissolved silicate (DSi)at the sediment-water interface in Jiaozhou Bay were measured by intact sediment cores incubation.Further,the impacts of environmental factors on the exchange rate were also discussed.Silicate transported from sediment to overlying water,and the exchange rate ranged from 947 to 4 889 μmol/(m2 ·d)with a mean of 1 819 μmol/(m2 ·d).Total organic carbon (TOC )and chlorophyll a(Chl a)in surface sediment which were relative with the biological activity were the dominant factors controlling the ex-change rate of DSi.Moreover,water ratio(φ),biogenic silicate(BSi),clay content of sediment and DSi in the pore water also had important effects on the exchange process.As a result,the exchange of DSi at the sediment-water interface in Jiaozhou Bay was a consequence of dissolution-dilution process which was dominantly controlled by bio-logical activity.Grain diameter of sediment and DSi in bottom water,however,were not relatively important when compared with those factors.%采用实验室培养法在原位温度和溶氧条件下测定了胶州湾沉积物－海水界面硅的交换速率，并探讨了相关环境因子对界面交换速率的影响机制。结果表明，胶州湾沉积物－海水界面硅的交换表现为从沉积物向水体释放，其交换速率在947～4889μmol／（m2·d）范围内，平均速率为1819μmol／（m2·d）。表层沉积物中叶绿素 a（Chl a）和总有机碳（TOC）是影响胶州湾沉积物－海水界面硅交换速率的主要环境因子，同时表层沉积物的含水率（φ）、生源硅（BSi）和粘土含量以及间隙水中溶解硅酸盐（DSi）对沉积物－海水界面硅的交换也有重要影响。由此可推知，胶州湾沉积物－海水界面硅的交换速率主要受生物活动和溶解－扩散双重过程调控，而表层沉积物粒度与底层水体中 DSi 对胶州湾硅的释放影响较小。