Toxic effects of diesel oil on Arbacia dufresnii gametes during early developmental stages

Abstract

Marine pollution by petrogenic hydrocarbons from crude oil and its derivatives is a major environmental concern, particularly in regions with intensive maritime activities. Diesel oil, widely used in shipping, can impair reproductive processes in marine organisms. Arbacia dufresnii is an ecologically and commercially important sea urchin from Patagonia, Argentina, where oil extraction, port operations, and maritime traffic increase the risk of petrogenic hydrocarbon contamination. This study aimed to evaluate the toxic effects of diesel oil on A. dufresnii gametes, assessing sex-specific sensitivity through fertilization, hatching, larval survival, and early developmental morphology. Female and male gametes were exposed separately to diesel oil in seawater (0.012%, 0.025% v/v, and 0% (control)) in two independent, asynchronous bioassays. Exposed gametes were fertilized with unexposed counterparts, and fertilization success, hatching dynamics, larval survival, and morphological abnormalities were assessed during early development, up to 12 days post-fertilization. Results revealed clear sex-specific sensitivity to diesel oil. Male gametes showed reduced fertilization success and altered hatching dynamics, whereas female gametes exhibited reduced larval survival. Morphological abnormalities were observed in embryos and larvae from both male- and female-exposed gametes, indicating sublethal disruption of early developmental processes. These findings demonstrate that short-term exposure to diesel oil can impair multiple early life stages of A. dufresnii, with potential consequences for recruitment and population resilience. The study highlights the importance of considering gamete-specific sensitivity and multiple early developmental endpoints in environmental risk assessments of hydrocarbon pollution in coastal ecosystems.