Análises multicriteriais dos efeitos da exposição ao óleo cru em organismos recifais

Abstract

Reefs are habitats rich in biodiversity but vulnerable to pollutants such as crude oil, which cause morphological, behavioral, physiological and genetic damage to organisms due to the bioaccumulation of hydrocarbons and metals. The objective of this study is to evaluate, both in situ and ex situ, the toxic effects of oil exposure on Palythoa variabilis, a common cnidarian in Brazilian reefs. Initially, a systematic literature review was conducted to gather current data on the acute effects of crude oil on Cnidaria. The search covered articles published between 2013 and 2023 using the terms: “crude oil” AND acute AND (Cnidaria OR coral) and the classes that compose the phylum. Twenty-eight articles were retrieved, highlighting the limited number of studies, with 2022 being the most productive year. The articles focus on evaluating responses from the major groups of adult cnidarians (Class Anthozoa, Order Scleractinia) and are experimental, but they present varied methodologies, indicating a need for standardization. The approaches are employed independently, making it essential to analyze the relationships between bioaccumulation and effects on health, behavior, physiology, genetics and different taxa, so studies on the topic need to fill these gaps. Subsequently, the in situ effect of oil was evaluated, analyzing the relationship between PAHs and elements in the sediments and bioaccumulated by P. variabilis from two beaches in Pernambuco (Muro Alto - directly impacted by the 2019 oil spill and Serrambi - indirectly impacted) and the oil sludge that reached the Brazilian coast, assessing the generation of oxidative stress and genetic damage in the animals. There is a correlation between the composition of PAHs in the sediments of both beaches and in the oil sludge. The elements Ba, Cd, Cu, Pb, As, and V bioaccumulated are correlated with oxidative and genetic damage. In the sediments, Al, Cu, Ni, and Co are correlated with oxidative damage. The main PAHs responsible for inducing biological responses were bioaccumulated fluorene and phenanthrene in the sediments. Finally, ex situ analyses of the effect of PAHs from crude oil on P. variabilis were conducted. Polyps collected in Serrambi (PE) and acclimated were exposed to WAF for 96 hours (25% WAF, 12.5% WAF and control group). Acute exposure induces behavioral alterations, oxidative stress, and sublethal genetic damage. These results have potential for use in oil spill damage mitigation strategies by providing the mechanisms of sublethal responses of the animals, strengthening efforts to conserve reef ecosystems.