Bioaccumulation, Subcellular Distribution, and Trophic Transfer of Copper in a Coastal Marine Diatom

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• 作者：Sung Il Chang and John R. Reinfelder
• 刊名：Environmental Science & Technology
• 出版年：2000
• 出版时间：December 1, 2000
• 年：2000
• 卷：34
• 期：23
• 页码：4931 - 4935
• 全文大小：66K
• 年卷期：v.34,no.23(December 1, 2000)
• ISSN：1520-5851

文摘

Cellular uptake and subcellular distribution of copperwere measured in the coastal marine diatom Thalassiosiraweissflogii grown with free Cu ion concentrations (10^-14.79-10^-9.79 M) that are typical of coastal waters. IntracellularCu quotas increased 2-3-fold and 4-5-fold per decadeincrease in free Cu ion concentration over the pCu(pCu = -log [Cu²⁺]) ranges of 14.79-11.79 and 11.79-9.79, respectively. The trophically available cytoplasmic poolof Cu increased by 2 orders of magnitude in T. weissflogiicells (0.53 × 10^-17-75 × 10^-17 mol Cu cell^-1) grownwith 10^-14.8-10^-9.8 M free Cu. A 2-fold increase in intracellularand cytoplasmic Cu concentrations was observed inresponse to lowering the free concentration of the potentiallyantagonistic metal Zn by a factor of 10. However, thepercent of intracellular Cu in the cytoplasmic fraction ofT. weissflogii ( 40%) was relatively constant over the rangeof cupric ion activities and [Cu²⁺]:[Zn²⁺] ratios applied.The assimilation efficiency (AE) of copper in marine copepodsfed T. weissflogii, determined using the inert-tracer ratiomethod, was 40.3 ± 6.3% for copepods fed diatoms grownat pCu = 12.79 and 50.3 ± 9.7% for copepods fed diatomsgrown at pCu = 10.79. Our results suggest that, abovefree Cu concentrations of 10^-11.8 M, the availability of Cufor trophic transfer in coastal waters increases as a resultof rapidly increasing concentrations of Cu in the assimilable,cytoplasmic fraction of diatoms and potentially higherCu AEs at the base of the pelagic food web.