Bacterial Diversity in an Amazonian Mangrove Ecosystem

Abstract

Mangroves form a transition zone among terrestrial, marine, and freshwater environments, and they host a striking diversity of macro- and microorganisms. In recent years, increasing anthropogenic impacts have caused widespread degradation of mangrove environments. To analyze the bacterial diversity of Salina Lake, an artificial body of water located in the mangroves of eastern Amazonia, total DNA was extracted from sediment and water samples that were collected from three sites (P1, P2, P3) located within the lake. The 16S rRNA gene was partially amplified, separated using the Denaturing High Performance Liquid Chromatography (DHPLC) method, and sequenced. The DHPLC profiles were quite distinct for the different aquatic and sedimentary bacterial communities. The most abundant groups (> 70%) at all sampled locations were Proteobacteria and unclassified bacteria, but other phyla were also identified, including Bacteroidetes, Cyanobacteria, Acidobacteria, Firmicutes, Actinobacteria, Chloroflexi, Siprochaetes and TM7. A total of 24, 15, and 23 OTUs (Operational Taxonomic Units) were observed in the water samples from P1, P2, and P3, respectively, whereas the sediment samples returned 29, 34, and 52 OTUs. This is the first analysis performed on the bacterial diversity of Salina Lake, which was created by the construction of a highway within a protected mangrove area.