Metal uptake in a coastal diatom influenced by major nutrients (N, P, and Si).
The influence of major nutrient additions on trace metal uptake (Cd, Se, and Zn) in a coastal diatom Thalassiosira pseudonana was investigated. A short-term exposure (5 h) was employed to measure the concentration factor (ratio of metal concentration in the cells to metal concentration in the medium) which was used as a kinetic parameter to quantify the relative rate of metal uptake in the cells. Following an initial rapid surface sorption, a linear pattern of uptake over time was typical for Cd, Se and Zn, indicating that these metals may have been transported intracellularly during the short-term exposure period. N addition significantly increased the rates of Cd uptake in the cells. Although the concentration factor of Zn increased with N addition, statistical analysis indicated that N addition did not significantly affect the rate of Zn uptake in the cells. Se uptake in the cells was independent of N additions, but was lowered with increasing Si concentration. Si addition did not significantly affect Cd and Zn uptake. Similarly, P addition did not influence the rates of metal uptake in the cells. There was a significant correlation between the rate of uptake of Cd and Zn and the cell growth rate. This study demonstrated that water quality brought about by a change in nutrient condition could considerably influence the uptake of metals by marine phytoplankton.
Department of Biology, Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong. wwang@ust.hk
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D002104:Cadmium / Q000378:metabolism; D017377:Diatoms / Q000254:growth & development / Q000502:physiology*; D006723:Hong Kong; D007700:Kinetics; D008670:Metals / Q000378:metabolism*; D009584:Nitrogen; D010758:Phosphorus; D012623:Seawater; D012643:Selenium / Q000378:metabolism; D012825:Silicon; D015032:Zinc / Q000378:metabolism
D008670:Metals; D002104:Cadmium; D010758:Phosphorus; D012643:Selenium; D015032:Zinc; D009584:Nitrogen; D012825:Silicon