Effects of sediment-associated phenanthrene on survival, development and reproduction of two species of meiobenthic copepods

Abstract

The lethal and sublethal toxlclty of phendnthrene (a polycyclic aromatic hydrocarbon, PAH) to 2 species of meiobenthic estuarine harpacticoid copepods (Schfzopera knabeni dnd Nitocra lacustrfs) was ~nvestlgated Individuals of different life stages ( n a u p l ~u s copepodite, adult male and female) were exposed to sediment-associated phenanthrene In separate 10 d bioassays Overall A' lacustns (10 d LCj, values ranglng from 43 to 105 pg g ' d ~y wt) was more sensitive than S knabeni (10 d LCSD values ranging from 84 to 349 pg g ' dry \vt) Signlflcant differences In life-stage-speclfic sensitivity wele observed for S knabeni, with the nauplll belng most seniltive tolloived by copepodltes and adults, adult males and females \Yere equally sensltlve For N Iacustris females wele significantly more sensltlve than all other stages no s i g n ~f ~c a n t d~tferences \yere evldent among the other stages Phenanthrene effects on offspring productlon were invest~gated In the adult 10 d b~oassay Significant decreases in offspring productlon occurred at sublethal concentratlons for S knabenl (as low as 22 1-19 g.' d r y wt) but d t concentratlons In the same lange as the 10 d LC5,values for A' ldcustr~s In addition phenanthrene slgnlficantly prolonged embryonic and larval development and decreased e g g hatching success for both species Our results suggest that PAHs have a negative effect on the reprod u c t ~o n of melobenthic copepods at sublethal concentrations mostly due to a decrease In brood prod u c t ~o n rate and impalrlnent of hatchlng Overall, deleterious effects were manifested in the same range of concentratlons for both species but deflnite specles-spec~flc differences In the pattern of responses were evident