Oil Spill Disaster in Southwest Atlantic Coast: an Evaluation of Short-Term Effects on Coral Reef Benthic Assemblages

Abstract

Oil pollution has significantly contributed to coral reef decline in the last five decades and a major oil spill reached Brazilian tropical coast in August 2019. Here, we report the first evidence of direct crude oil contact from that spill on reef coral species, and evaluate the effects of this disaster on coral vitality and benthic assemblage structure on the largest coastal marine protected area (MPA Costa dos Corais) in Brazil. We compared benthic cover in reefs with and without oil and monitored Siderastrea stellata colonies 90 days after oil contact. Oil stains between 0.5 and 150 cm were found in two of the 17 reef sites investigated. Multivariate analyses did not detect significant differences between oiled and non-oiled reefs and there was no evidence of S. stellata health deterioration. These results indicate minimal acute effects on coral vitality and intertidal reef benthic assemblage structure. Future studies should investigate oil effects on specific aspects of coral biology as growth, reproduction, bleaching susceptibility and metagenomics which can deteriorate over longer time frames, and we recommend long-term coral reef monitoring to support a robust assessment and mitigation of chronic oil impacts.