N-177. Structure and Functional Analyses of Bacterial Communities from a Brazilian Mangrove Contaminated with Petroleum

F. A. Paes1,2, V. M. M. Melo1, T. L. Marsh2, J. M. Tiedje2;
1UFC, Fortaleza, BRAZIL, 2Michigan State Univ., East lansing, MI.

Mangroves are biologically important and productive intertidal ecosystems along subtropical and tropical coastlines. Undisturbed mangroves provide habitats for a variety of plants, microorganisms and animals. These ecosystems receive sedimentary materials from both sea and continent, becoming a transitory area with high productivity. Important processes such as nutrient cycling are directly connected to the activity and diversity of the microbial communities of mangrove soils. Even though, because of their strategically location, mangroves have been widely impacted around the world. Understanding the structure and functions of microbial communities and their adaptations to environmental alterations resulting from xenobiotics, climate change and industrial practice is essential to maintaining or restoring desirable ecosystem functions. The present study investigated the structure and function of bacterial communities in a Brazilian mangrove strongly polluted by the petroleum industry. Three sites were sampled - two of which were located inside an exploration and refinery area and the other located outside that area and served as a control. Two culture-independent methods were used: T-RFLP (enzymes HhaI and MspI) and microarrays (Zhili He, AEM v.71 (9), 5154-5162). Results obtained from both methodologies and the abiotic site data were statistically analyzed by PCA. Compared to the control, the impacted samples showed different community structures. For the site located near the petroleum refinery area, the low amount of OTUs suggested an inhibition by the petroleum spills. Also, the microarrays showed an enrichment of genes associated with organic remediation and methane degradation. All sites were grouped separately by PCA and, besides the hydrocarbons contamination, pH and phosphorus also seem to influence the bacterial communities. We conclude that the structure and function of the bacterial communities were strongly affected by the presence of the petroleum industry. Further studies will help us to also understand the dynamics of those communities following petroleum exposure.