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अमूर्त

Impact of Sediment from St. Jones River, Delaware, USA on Microbial Functional Stability in Two Local Soils

Qiquan Wan, Esosa Iriowen1, Shoujun Yuan and Donald L. Sparks

For the purposes of navigation, flooding 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 significant 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.