Chong K, Wang W
Department of Biology, The Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong
J Exp Mar Biol Ecol. 2000 Dec 1;255(1):75-92. doi: 10.1016/s0022-0981(00)00296-3.
We assessed the degree to which Cd, Cr and Zn bound with sediment were assimilated by the green mussel Perna viridis and the Manila clam Ruditapes philippinarum. The influences of the metal concentration in the sediment, the presence of phytoplankton, and the oxidation condition of the sediment on metal assimilation were examined. No major difference was found for metal assimilation efficiency (AE) in sediment with different metal concentrations, except for Cd in the green mussels, in which the AE increased by 1.7x when the Cd concentration in sediment was elevated to 15x the natural background level. The higher assimilation of Cd with increasing Cd load in ingested sediment may be due to the higher desorption of Cd in the acidic gut of the bivalves. Both mussels and clams assimilated metals at a higher efficiency from the diatom diet (Thalassiosira pseudonana) than from inorganic sediment particles. The presence of algal particles had little influence on metal assimilation from ingested sediment, and conversely, the presence of sedimentary particles had little effect on metal assimilation from ingested diatom (except for Cd in the mussels). In the mussels, AEs were higher from oxic sediment than from anoxic sediment by 3.1x for Cd, 2.0x for Cr, and 1.4x for Zn, and in the clams AEs were higher from oxic sediment by 2.8x for Cd, 2.0x for Cr, and 2.0x for Zn. Our study suggested that metals associated with anoxic sediment can be potentially available to marine bivalves, and that metal AEs determined for a single diet were probably not affected by the presence of other food particles.
我们评估了与沉积物结合的镉（Cd）、铬（Cr）和锌（Zn）被翡翠贻贝（Perna viridis）和菲律宾蛤仔（Ruditapes philippinarum）同化的程度。研究了沉积物中金属浓度、浮游植物的存在以及沉积物的氧化条件对金属同化的影响。除了翡翠贻贝中的镉之外，不同金属浓度的沉积物在金属同化效率（AE）方面未发现重大差异，当沉积物中的镉浓度升高至自然背景水平的15倍时，翡翠贻贝中镉的同化效率提高了1.7倍。随着摄入沉积物中镉含量增加，镉的同化率更高，这可能是由于双壳贝类酸性肠道中镉的解吸率更高。贻贝和蛤仔从硅藻食物（假微型海链藻，Thalassiosira pseudonana）中同化金属的效率均高于从无机沉积物颗粒中同化的效率。藻类颗粒的存在对从摄入沉积物中同化金属的影响很小，相反，沉积颗粒的存在对从摄入硅藻中同化金属的影响也很小（贻贝中的镉除外）。在贻贝中，有氧沉积物中镉、铬和锌的同化效率分别比缺氧沉积物高3.1倍、2.0倍和1.4倍；在蛤仔中，有氧沉积物中镉、铬和锌的同化效率分别比缺氧沉积物高2.8倍、2.0倍和2.0倍。我们的研究表明，与缺氧沉积物相关的金属对海洋双壳贝类可能具有潜在可用性，并且单一食物的金属同化效率可能不受其他食物颗粒存在的影响。
