Effect of diesel fuel hydrocarbons on embryogenesis and 45Ca2+ uptake by unfertilized eggs of sea urchin, Strongylocentrotus intermedius

Abstract

1. The quality of unfertilized eggs of the sea urchin Strongylocentrotus intermedius, kept for a long time (50 days) in a sea water containing water soluble hydrocarbons of diesel fuel in sublethal concentrations (0.3–0.04 mg/l), was assessed through observation of embryogenesis and the intensity of ⁴⁵Ca²⁺ uptake.

2. It has been shown that such treatment led to delay and asynchronism of embryonal and larval development and to appearance of a greater number of abnormalities compared to the control.

3. Unfertilized eggs of sea urchins exposed to the hydrocarbons in sublethal concentrations accumu- lated 30–60% more ⁴⁵Ca²⁺ than those of control animals. Short-term incubation (2 hr) of eggs at the same hydrocarbon concentrations did not change ⁴⁵Ca²⁺ uptake by unfertilized eggs of control animals.

4. The increase of hydrocarbon concentration up to 1 mg/l (i.e. to a concentration causing disturbance of embryogenesis in acute experiments) in short-term experiments caused a small elevation in the ⁴⁵Ca²⁺ uptake by unfertilized eggs of control animals (30% more than in untreated eggs).

5. Ionomycin-induced (concentration 10⁻⁸−10⁻⁹) increase of ⁴⁵Ca²⁺ uptake by unfertilized eggs (50–100% more than the untreated eggs) caused the same disturbance of embryogenesis as under hydrocarbon exposure.

6. It is suggested that one of the mechanisms inducing the deleterious effect of hydrocarbons in sea urchin gametes is related to the increase of membrane permeability to calcium ions.