Mangrove Bacterial Diversity and the Impact of Oil Contamination Revealed by Pyrosequencing: Bacterial Proxies for Oil Pollution

Abstract

BackgroundMangroves are transitional coastal ecosystems in tropical and sub-tropical regions and represent biologically important and productive ecosystems. Despite their great ecological and economic importance, mangroves are often situated in areas of high anthropogenic influence, being exposed to pollutants, such as those released by oil spills.Methodology/Principal FindingsA microcosm experiment was conducted, which simulated an oil spill in previously pristine mangrove sediment. The effect of the oil spill on the extant microbial community was studied using direct pyrosequencing. Extensive bacterial diversity was observed in the pristine mangrove sediment, even after oil contamination. The number of different OTUs only detected in contaminated samples was significantly higher than the number of OTUs only detected in non-contaminated samples. The phylum Proteobacteria, in particular the classes Gammaproteobacteria and Deltaproteobacteria, were prevalent before and after the simulated oil spill. On the other hand, the order Chromatiales and the genus Haliea decreased upon exposure to 2 and 5% oil, these are proposed as sensitive indicators of oil contamination. Three other genera, Marinobacterium, Marinobacter and Cycloclasticus increased their prevalence when confronted with oil. These groups are possible targets for the biomonitoring of the impact of oil in mangrove settings.Conclusions/SignificanceWe suggest the use of sequences of the selected genera as proxies for oil pollution, using qPCR assessments. The quantification of these genera in distinct mangrove systems in relation to the local oil levels would permit the evaluation of the level of perturbance of mangroves, being useful in field monitoring. Considering the importance of mangroves to many other environments and the susceptibility of such areas to oil spills this manuscript will be of broad interest.

Remarkable impact of PAHs and TPHs on the richness and diversity of bacterial species in surface soils exposed to long-term hydrocarbon pollution

“…They claimed that the bacterial diversity changes inversely to the degree of TPH concentration. On the other hand, the positive effect of TPHs on the structure of bacterial community was also demonstrated in several other studies (Nie et al 2009;dos Santos et al 2011;Lee et al 2011;Li et al 2005).…”

Crude Oil Metagenomics for Better Bioremediation of Contaminated Environments

“…Similarly, the abundance of other dominant groups in polluted environments has also been reported; in fact, Actinobacteria, Firmicutes, and Bacteroidetes were described to be also dominant (Chang et al, 2000;Popp et al, 2006). Recently, Dos Santos et al (2011) studied the effect of the oil spill on the existing microbial community using direct pyrosequencing, which confirmed that the phylum Proteobacteria, in particular the classes Gammaproteobacteria and Deltaproteobacteria, were prevalent before and after the simulated oil spill. The authors claim that the order Chromatiales and the genus Haliea, and three other genera, Marinobacterium, Marinobacter, and Cycloclasticus increased, which make them possible targets for the biomonitoring of the impact of oil in mangrove settings.…”

Geo-Chip analysis reveals reduced functional diversity of the bacterial community at a dumping site for dredged Elbe sediment

“…Various studies have demonstrated the capacity of functional gene arrays to detect microbial community responses to environmental stressors Liu et al, 2010;Wang et al, 2009;Ward et al, 2007;Wu et al, 2008;Yergeau et al, 2007;Zhou, 2003), including heavily contaminated habitats (Lu et al, 2012;Neufeld et al, 2006;Van Nostrand et al, 2009;Xie et al, 2011). The results of these studies and other approaches evaluating the response of bacterial communities on environmental perturbation (chemically or physically) have demonstrated changes in the respective community structure and function (dos Santos et al, 2011;Findlay et al, 1990;Suarez-Suarez et al, 2011), thereby forming the basis for our hypothesis.…”