Chronic adverse effects of the oil dispersed sediments on benthic copepods: Ultimate effects on the individuals and populations

Abstract

To evaluate the effects of sediment assembled crude oil on acute (survival, egg damages, feeding) and chronic (growth, reproduction) result, the benthic copepod T. japonicus was exposed to crude oil polluted sediments. For direct exposure to the sediment, 6h exposure cause significant damages on the eggs of ovigerous females. Accidental oil spill have causes ecological risks in aquatic environment. Oil attached to sediments has received great concern because effective technologies and equipment to remove oil from fine grains have not been developed sufficiently. In this study, copepod T. japonicus was exposed to oil dispersed sediments (<75μm grain size) and its biological repercussions were measured from molecular to individuals levels. Adult and nauplius of T. japonicus were exposed to oil polluted sediments. In exposure group, molecular responses (antioxidant genes) were detected caused by oil dispersed sediments. For copepodid at C3 and C4 stages, the growth retardation was measured in test group for 10 days exposure to oil polluted sediments. For adult T. japonicus, survival rate was not observed but their reproduction rate (number of ovigerous female and their hatching success) was significantly reduced. The inhibition of assimilation rate of diet (Tetraselmis suecica) was also tested separately using 13C labeled phytoplankton. This study showed diverse end-points of T. japonicus can be markers for oil dis to the sediment, 6h exposure cause significant damages on the eggs of ovigerous females. Accidental oil spill have causes ecological risks in aquatic environment. Oil attached to sediments has received great concern because effective technologies and equipment to remove oil from fine grains have not been developed sufficiently. In this study, copepod T. japonicus was exposed to oil dispersed sediments (<75μm grain size) and its biological repercussions were measured from molecular to individuals levels. Adult and nauplius of T. japonicus were exposed to oil polluted sediments. In exposure group, molecular responses (antioxidant genes) were detected caused by oil dispersed sediments. For copepodid at C3 and C4 stages, the growth retardation was measured in test group for 10 days exposure to oil polluted sediments. For adult T. japonicus, survival rate was not observed but their reproduction rate (number of ovigerous female and their hatching success) was significantly reduced. The inhibition of assimilation rate of diet (Tetraselmis suecica) was also tested separately using 13C labeled phytoplankton. This study showed diverse end-points of T. japonicus can be markers for oil dis