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Effects of Cd on Dissolved Organic Matters in Mangrove Sediments(PDF)

Chinese Journal of Applied & Environmental Biology[ISSN:1006-687X/CN:51-1482/Q]

2008 NO.02
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Effects of Cd on Dissolved Organic Matters in Mangrove Sediments
YE Binbinet al.
(Laboratory of Pollution Ecology, School of Life Sciences, Xiamen University, Xiamen 361005, Fujian, China)
Keywords cadmium dissolved organic carbon dissolved organic nitrogen mangrove sediment rhizosphere

Abstract Soilculture medium was used to investigate the effects of cadmium on dissolved organic carbon (DOC) and nitrogen (DON) in mangrove sediments. The seedlings of Kandelia candel (L.) Druce were cultured in greenhouse supplied with a series of cadmium concentrations (0~50 mg kg-1 ) from the beginning of May to the end of December in 2004. After harvest, the contents of DOC and DON in mangrove sediments were measured. The results showed that the content of DOC decreased first at lower Cd levels, which might be regarded as a selfprotecting function of plants. After they reached the lowest value (0.134 mg g-1) at cadmium concentration of 10 mg kg-1, the content of DOC increased, reaching the peak value (0.190 mg g-1) at cadmium concentration of 30 mg kg-1. The content of DON had two lowest values (0.075 mg g-1 and 0.081 mg g-1), when the cadmium concentrations were 5 mg kg-1 and 20 mg kg-1. And it reached the peak values, 0.117 mg g-1 and 0.138 mg g-1, when cadmium concentrations were 10 mg kg-1 and 30 mg kg-1, respectively. These results indicated that DOC and DON in mangrove sediments could be combined with cadmium at its lower concentration. Higher concentration of cadmium might induce more root secretion and metabolizable production from mangrove, and result in the increase of DOC and DON. Compared with nonrhizosphere soil, both contents of DOC and DON in rhizosphere were higher than those in any other soil layers, indicating that relatively high DOC and DON contents presented in rhizosphere soil. Fig 3, Tab 2, Ref 18




Last Update: 2008-04-23