ISSN: 2155-6199 JBRBD, an open access journal Bioremediation: Environmental Microbiology J Bioremed Biodegrad Research Article Open Access Wang, et al. J Bioremed Biodegrad 2011, S:1 http://dx.doi.org/10.4172/2155-6199.S1-005 Research Article Open Access Bioremediation & Biodegradation Keywords: Sediment; Soil microbial function; Functional stability; Resistance; Resilience Introduction For the need of navigation, looding prevention, and/or environmental protection, large volumes of costal and inland aquatic sediments have to be scooped periodically [1,2]. It was estimated that 100~200 Mm 3 of sediment are dredged in Europe and 600 Mm 3 worldwide annually [3,4]. Applying sediment as fertilizer in agricultural lands [5] and using it as constructional material in public works [4] have been proposed. Disposal to storage sites or nearby embankments without further treatment or precaution was also reported [6]. However, proper disposal or remediation is required when contaminated sediments, especially those from historically contaminated areas, are dredged [1]. he management of dredged sediment greatly depends on its potential risks to the environment, which are commonly assessed by chemical analysis of heavy metals and various toxic organic contaminants [7]. he impact of dredged sediment on soil microbial communities is oten neglected. Soil is a fascinating biological system with inhabiting microorganisms, which are of paramount importance for soil functioning in nutrient cycling, substance decomposition, and energy low. About 80-90% of the processes in soil are mediated by microbes [8,9]. However, anthropogenic activities, such as cultivation and pollution, may alter sensitive soil microbial communities and result in changes of soil functional activities [10]. hus a great attention has been paid to the changes of soil microbial diversity caused by various disturbances [11,12]. Meanwhile, soil microbial community functions, such as soil microbial and enzymatic activities/potentials, have also been investigated as afected by various pollutants, including heavy metals [13,14], veterinary antibiotics [15], pesticides [16], organic wastes [17], and petroleum [18]. A growing amount of experimental evidences indicates no consistent relationship between microbial diversity and soil functions [19-21]. he impact of various perturbations on soil microbial functions is generally assessed based on the measurement of soil functional stability, including resistance and resilience [12,22]. It has been found that soil functional resistance greatly depends on the nature and concentration of contaminants, the nature of soil, and the species of enzymes [13,23,24]. When the impact of a primary disturbance/stress on soil functional stability is diicult to observe, its impact can also be assessed by exerting a secondary standard disturbance, such as heat shock and drying-rewetting cycle [25]. he soil received the primary disturbance may or may not appear less stable to the secondary disturbance than the soil without the primary disturbance/stress. For example, mercury- contaminated showed to have reduced resistance to heat compared the non-contaminated soil [26]. his study aims at a preliminary understanding of the impact of sediment from St. Jones River on the microbial functional stability in two local soils. St. Jones River is a tidal river located in Central Delaware State, USA (Figure 1). It begins at the dam of the Silver Lake in Dover, the state capital city, and lows southeastwardly to Delaware Bay on the *Corresponding author: Qiquan Wang, Department of chemistry, Delaware State University, Dover, DE 19901, USA, Tel: +001 (302) 857-6547; Fax: +001 (302) 857- 6539, E-mail: qwang@desu.edu Received October 24, 2011; Accepted December 21, 2011; Published December 23, 2011 Citation: Wang Q, Iriowen E, Yuan S, Sparks DL (2011) Impact of Sediment from St. Jones River, Delaware, USA on Microbial Functional Stability in Two Local Soils. J Bioremed Biodegrad S1:005. doi:10.4172/2155-6199.S1-005 Copyright: © 2011 Wang Q, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Abstract For the purposes of navigation, looding prevention, and/or environmental protection, aquatic sediment may need to be dredged and disposed. The impact of sediment on soil microbial communities is often neglected. In this study, two fresh sediment samples (A & B) from St. Jones River, Delaware, USA were amended into two different local soils, an agricultural soil and a forest soil. Eight microbial and enzymatic activities were selected to represent soil microbial functions and the impact of sediment amendment on soil microbial functional stability was determined. Based on the values of average resistance, which is the average of the absolute value of resistance in each activity, no signiicant difference was observed between the impacts of those two sediments on the microbial functional resistance in the agricultural soil. The average resistance values of the forest soil to the amendment of sediment B at 2 and 10% were at least 0.3 times lower than that in the agricultural soil, indicating that the forest soil was more resistant than the agricultural soil to sediment amendment. The forest soil appeared more sensitive to sediment amendment in the resistance to heat than the agricultural soil, but exhibited a bigger capacity tolerating the sediment amendment at the high percentage. Both soils were weakened in resilience from the heat disturbance by sediment amendment at 10%. Hence, microbial functional stability in these two local soils was markedly impacted by sediment amendment. The nutrient cycling of N, P, and S in two local soils was greatly depressed and easily-available organic-C was promptly consumed with sediment amendment. Heavy metal remediation and/or protective storage might need to be considered for sediment from St. Jones River when it is dredged in the future. Impact of Sediment from St. Jones River, Delaware, USA on Microbial Functional Stability in Two Local Soils Qiquan Wang 1 *, Esosa Iriowen 1 , Shoujun Yuan 1,2 and Donald L. Sparks 3 1 Chemistry Department, Delaware State University, Dover, DE 19901, USA 2 College of Civil Engineering, Hefei University of Technology, Hefei, Anhui 230009, China 3 Department of Plant and Soil Sciences, University of Delaware, Newark, DE 19901, USA