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ISSN 1811-0231 / ISEIS Publication Series Number P002

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  Paper EIA06-002, Volume 4 (2006), Pages 26-34 = complimentary

Study of Exchangeable Nitrogen and Their Bioavailability in the Sediments

A. Zheng1*, H. Shen2 and D. Chen1

1. Department of Oceanography/Institute of Subtropical Oceanography, Xiamen University, Xiamen 361005, China. *Corresponding author: arzheng@jingxian.xmu.edu.cn.

2. Graduate School of Oceanography, University of Rhode Island, Narragansett 02882, USA.

 

Abstract

The contents of exchangeable nitrogen (NEX) in the sediments of the Daya Bay, the Zhujiang River Estuary and the Xiamen Bay are measured with extraction solution of KCl. Their availabilities to Chlorella sp. and Isochrysis galbana are estimated by using these sediments as the sole source of nitrogen in the bioassays. The results showed that the contents of NEX in the sediments are 41.8, 33.6 and 37.7 mg/kg, respectively. The contents of NEX in these sediments are principally in the presentation of NH4+, and exchangeable NH4+accounts for 62.2~78.5% of NEX. The greatest relative growth rates of Chlorella sp. and Isochrysis galbana cultured with the sediments as the sole source of nitrogen are in the range of 5.4~14.8%. The utilization rates of NEX in three sediments by two algae vary from 9.5 to 20.4%. All this suggested that NEX can be transformed from sediment into solution and utilized by algae.


Keywords: sediment, nitrogen, bioavailability

 

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