Responses of benthic foraminifera to the 2011 oil spill in the Bohai Sea, PR China

The 2011 oil spill in the Bohai Sea was the largest spill event in China. Nine sediment cores were taken near the spill site and environmental factors including Polycyclic Aromatic Hydrocarbon (PAHs), oils, sulfides, organic carbon were measured 6 months later. Benthic foraminifera were separated into >150 μm (large) and 63-150 μm (small) size fractions for 2-cm depth interval of each sediment core. Statistical analyses suggested that the species composition of living foraminifera was impacted by oils, PAHs and sulfides. Large foraminifera were more sensitive to the oils than the small. Abnormal specimens were positively correlated with oils or PAHs. Small forms, however, tended to have high reproduction and mortality. Pollution-resistant and opportunistic taxa were identified to calculate a Foraminiferal Index of Environmental Impacts (FIEI). The FIEI increased from low to high oil-polluted station and from deep layer to surface sediment reflects the impact of oil pollution in this area.