Sanders J G, Abbe G R, Riedel G F
Academy of Natural Sciences, Benedict Estuarine Research Laboratory, MD 20612.
Sci Total Environ. 1990 Nov;97-98:761-9. doi: 10.1016/0048-9697(90)90273-w.
Silver within Chesapeake Bay is rapidly taken up by phytoplankton, in accordance with geochemical controls over silver speciation. Phytoplankton accumulate large cellular burdens at non-lethal concentrations, setting up the potential for transfer of silver to herbivores that graze upon the phytoplankton community. However, the American oyster, Crassostrea virginica, does not assimilate silver from phytoplankton, but rather from that dissolved in water. Oysters can accumulate high burdens of silver via this uptake pathway, without apparent effect. There is another, perhaps more significant, mechanism by which silver can impact higher trophic levels. Continuous inputs of low concentrations of silver can cause large changes in species composition and species succession in Chesapeake Bay phytoplankton communities maintained in experimental ecosystems. In addition, oyster growth was reduced significantly relative to growth of oysters of unaltered communities. Such indirect effects of low levels of toxic substances, although difficult to detect, must be considered when assessments of pollutant impacts are made.
切萨皮克湾中的银会迅速被浮游植物吸收，这与银形态的地球化学控制作用相符。浮游植物能在非致死浓度下积累大量细胞负荷，为银向以浮游植物群落为食的食草动物转移创造了可能性。然而，美洲牡蛎（Crassostrea virginica）并非从浮游植物中吸收银，而是从溶解在水中的银中摄取。通过这种摄取途径，牡蛎能够积累高负荷的银，且无明显影响。银还有另一种或许更重要的机制来影响更高营养级。持续输入低浓度的银会导致在实验生态系统中维持的切萨皮克湾浮游植物群落的物种组成和物种演替发生巨大变化。此外，与未改变群落中的牡蛎生长相比，实验群落中的牡蛎生长显著降低。低水平有毒物质的这种间接影响，尽管难以察觉，但在进行污染物影响评估时必须予以考虑。
