重金属在海洋食物链中的传递  

The transfer of metals in marine food chains: A review

作　　者：王文雄[1] 潘进芬[1] 

机构地区：[1]香港科技大学生物系

出　　处：《生态学报》2004年第3期599-604,共6页Acta Ecologica Sinica

摘　　要：近年来 ,金属在不同海洋食物链中摄食富集的定量研究得到越来越多的关注。自然环境中生物体内金属的浓度并不一定和生物在食物链中所处的营养级有相关关系 ,金属在生物体内的富集还受到生物的同化、排出等过程以及其它生理生化因子的影响。在经典的海洋浮游生物食物链中 (浮游植物→桡足类→鱼类 ) ,桡足类往往可以很有效地排出体内的金属 ,同时鱼类的金属同化率又很低 ,所以该食物链中金属的浓度随食物链水平增加而减少。目前研究发现只有甲基汞和铯 Cs会被食物链所放大。在以腹足动物为顶级捕食者的底栖食物链中 ,因为生物结合金属的效率很高 ,高同化率和低排出率导致金属浓度在生物体内得到放大。重金属在生物体内的可利用性可以通过测定同化率、排出率等参数、并结合考虑生物对该金属的消化行为 ,运用一个简易的动态模型来估算。已有的研究中人们多考虑金属的化学性质对食物链传递的影响。着重介绍了近年来国外对金属在不同海洋食物链 (底栖和浮游 )中的传递的研究成果 ,强调在金属的生物可利用性评估中 ,要充分考虑到动物的生理、生化过程的影响 。There are now increasing interests in the food chain transfer of metal contaminants in different marine food chains. The importance of metal dietary uptake in aquatic animals has been highlighted in many recent studies using both empirical experimental and modeling approaches. The application of bioenergetic-based kinetic model has played an important role in the delineation of the exposure of metal contaminants in the animals. This review summarizes the recent progress in this field, particularly on the measurements of a few important metal physiological parameters (e.g., assimilation efficiency from ingested food sources-AE, efflux rate constant during physiological turnover period) in several representative marine animals, including copepods, bivalves, gastropods and fish. Differences of these metal physiological parameters in different groups of marine animals are discussed. The potential trophic transfer factor (or biomagnification potential) of metals along marine food chains can be predicted based on a simple kinetic equation by incorporating metal AE, metal efflux rate and ingestion activity of the animals. With such approach, it is possible to dissect the complicate metal-food chain interaction in marine ecosystems. The transfer of a few metals (e.g., Cd, Hg, Zn) may be related to the trophic levels in the food chain, whereas for other metals, such trends are less obvious. At each trophic level, the potential biomagnification of metals is influenced either by metal AE only, or by metal efflux only, or by both assimilation and efflux. In the classical marine planktonic food chain (phytoplankton to copepods to fish), copepods can very efficiently remove the metals by their efflux systems, leading to a low metal concentration in the animals. The inter-species difference in metal AE is relatively small and metal AE is controlled by both metal distribution in the phytoplankton cytoplasm and metal gut passage across the copepod's gut. Typically particle reactive metals are less assimilated by the copepods as

关 键 词：重金属 海洋食物链 浓度 生物放大 无脊椎动物 鱼类 金属代谢机制 海洋生物 

分 类 号：X192[环境科学与工程—环境科学]