Significance of dredging on sediment denitrification in Meiliang Bay, China:A year long simulation study
Jicheng Zhong , Chengxin Fan , Lu Zhang , Edward Hall , Shiming Ding , Bao Li , Guofeng Liu
DOI:
Received March 17, 2009,Revised July 27, 2009, Accepted , Available online
Volume 22,2010,Pages 68-75
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An experiment for studying the e ects of sediment dredging on denitrification in sediments was carried out through a one-year
incubation of undredged (control) and dredged cores in laboratory. Dredging the upper 30 cm of sediment can significantly a ect
physico-chemical characteristics of sediments. Less degradation of organic matter in the dredged sediments was found during the
experiment. Denitrification rates in the sediments were estimated by the acetylene blockage technique, and ranged from 21.6 to 102.7
nmol N2/(g dry weight (dw) hr) for the undredged sediment and from 6.9 to 26.9 nmol N2/(g dw hr) for dredged sediments. The
denitrification rates in the undredged sediments were markedly higher (p < 0.05) than those in the dredged sediments throughout the
incubation, with the exception of February 2006. The importance of various environmental factors on denitrification was assessed,
which indicated that denitrification was regulated by temperature. Nitrate was probably the key factor limiting denitrification in both
undredged and dredged sediments. Organic carbon played some role in determining the denitrification rates in the dredged sediments,
but not in the undredged sediments. Sediment dredging influenced the mineralization of organic matter and denitrification in the
sediment; and therefore changed the pattern of inherent cycling of nitrogen.
