The uptake of zinc and cadmium by a species of marine diatom Thalassirosira weissflogii and the nutrient variation （ phosphorus and silicon） in the culture medium were estimated when exposed to zinc and cadmium stre...The uptake of zinc and cadmium by a species of marine diatom Thalassirosira weissflogii and the nutrient variation （ phosphorus and silicon） in the culture medium were estimated when exposed to zinc and cadmium stress under controlled laboratory conditions. It was found that low cadmium addition could stimulate the culture to grow with a relatively high rate and exert its toxicity at the elevated concentration. The cellular uptake of zinc and cadmium by the diatom varied in the ranges of 1.21 - 3.75 and 0. 060 - 0. 629 fmol per cell respectively in the whole cultivation period. The mean cellular phosphorus and silicon drawdowns were constant with 0. 26 - 0. 42 and 0. 30 - 0. 46 pmol per cell respectively in those healthy cultures. It is illustrated that the algal cells can adjust some physiological mechanisms to decrease metal accumulation and keep metal homeostasis in the organism. The correlation analysis results further indicate that the cellular cadmium uptake might be closely related with the cellular phosphorus, silicon drawdown and the growth rate of diatom （P 〈0. 05, 0. 001,0. 01 ） ; and the cultures grow better in good conditions, the lower amount of phosphorus, silicon materials are consumed by a single cell to keep a high efficiency of utilization.展开更多
The contents of total copper, total dissolved copper, particulate copper, and free ion copper in the Zhujiang River Estuary were investigated in July 2002 and January 2003 respectively, and the spatial distribution tr...The contents of total copper, total dissolved copper, particulate copper, and free ion copper in the Zhujiang River Estuary were investigated in July 2002 and January 2003 respectively, and the spatial distribution trend of these species of copper were compared in two cruises. It was found that, in summer, the total copper content in the Zhujiang River Estuary increased with salinity, while the content office ion copper decreased with salinity. However, in winter, the contents of total copper and free ion copper both decreased with salinity. So, it could be concluded that, copper content and speciation in the Zhujiang River Estuary were regulated by other factors than runoffdiffusion such as upwelling current. In order to prove the spatial trend of rice ion copper content in the Zhujiang River Estuary, the cultivation of Dunaliella tertiolecta in waters obtained from sampling stations with different salinities was carried out, and the copper uptake by algae cells was measured then. It was found that, the cells＇ uptake of copper increased with rice ion copper, not the content of total copper.展开更多
基金This work was supported by the National Natural Science Foundation of China under contract No. 40646031； the Foundation of Scientific and Technological Planning Project of Guangdong Province in China under contract Nos 2006B36601005 and 2005B33201007 and the Innovation Program of the Chinese Academy of Sciences under contract No. KZCX3 - SW - 227.
文摘The uptake of zinc and cadmium by a species of marine diatom Thalassirosira weissflogii and the nutrient variation （ phosphorus and silicon） in the culture medium were estimated when exposed to zinc and cadmium stress under controlled laboratory conditions. It was found that low cadmium addition could stimulate the culture to grow with a relatively high rate and exert its toxicity at the elevated concentration. The cellular uptake of zinc and cadmium by the diatom varied in the ranges of 1.21 - 3.75 and 0. 060 - 0. 629 fmol per cell respectively in the whole cultivation period. The mean cellular phosphorus and silicon drawdowns were constant with 0. 26 - 0. 42 and 0. 30 - 0. 46 pmol per cell respectively in those healthy cultures. It is illustrated that the algal cells can adjust some physiological mechanisms to decrease metal accumulation and keep metal homeostasis in the organism. The correlation analysis results further indicate that the cellular cadmium uptake might be closely related with the cellular phosphorus, silicon drawdown and the growth rate of diatom （P 〈0. 05, 0. 001,0. 01 ） ; and the cultures grow better in good conditions, the lower amount of phosphorus, silicon materials are consumed by a single cell to keep a high efficiency of utilization.
基金This work was supported by the Innovative Program of Chinese Academy of Sciences under contract No.kzcx3-sw-227 to Dr.Chen ShaoyongGuangdong Province Natural Science Fund under contract Nos 021560,04001313+1 种基金the Innovation Program of South China Sea Institute of Oceanology,Chinese Academy of Sciences under contract No.50601-32 to Long AiminScience and Technology Planning Program under contract No.2004B33201001 to Dr.Yan Wen and Long Aimin.
文摘The contents of total copper, total dissolved copper, particulate copper, and free ion copper in the Zhujiang River Estuary were investigated in July 2002 and January 2003 respectively, and the spatial distribution trend of these species of copper were compared in two cruises. It was found that, in summer, the total copper content in the Zhujiang River Estuary increased with salinity, while the content office ion copper decreased with salinity. However, in winter, the contents of total copper and free ion copper both decreased with salinity. So, it could be concluded that, copper content and speciation in the Zhujiang River Estuary were regulated by other factors than runoffdiffusion such as upwelling current. In order to prove the spatial trend of rice ion copper content in the Zhujiang River Estuary, the cultivation of Dunaliella tertiolecta in waters obtained from sampling stations with different salinities was carried out, and the copper uptake by algae cells was measured then. It was found that, the cells＇ uptake of copper increased with rice ion copper, not the content of total copper.
