Environmental science and pollution research international

Dispersed oil decreases the ability of a model fish (Dicentrarchus labrax) to cope with hydrostatic pressure.

PMID 27854059


Data on the biological impact of oil dispersion in deep-sea environment are scarce. Hence, the aim of this study was to evaluate the potential interest of a pressure challenge as a new experimental approach for the assessment of consequences of chemically dispersed oil, followed by a high hydrostatic pressure challenge. This work was conducted on a model fish: juvenile Dicentrarchus labrax. Seabass were exposed for 48xa0h to dispersant alone (nominal concentration (NC)xa0=xa04xa0mgxa0L(-1)), mechanically dispersed oil (NCxa0=xa080xa0mgxa0L(-1)), two chemically dispersed types of oil (NCxa0=xa050 and 80xa0mgxa0L(-1) with a dispersant/oil ratio of 1/20), or kept in clean seawater. Fish were then exposed for 30xa0min at a simulated depth of 1350xa0m, corresponding to pressure of 136 absolute atmospheres (ATA). The probability of fish exhibiting normal activity after the pressure challenge significantly increased from 0.40 to 0.55 when they were exposed to the dispersant but decreased to 0.26 and 0.11 in the case of chemical dispersion of oil (at 50 and 80xa0mgxa0L(-1), respectively). The chemical dispersion at 80xa0mgxa0L(-1) also induced an increase in probability of death after the pressure challenge (from 0.08 to 0.26). This study clearly demonstrates the ability of a pressure challenge test to give evidence of the effects of a contaminant on the capacity of fish to face hydrostatic pressure. It opens new perspectives on the analysis of the biological impact of chemical dispersion of oil at depth, especially on marine species performing vertical migrations.