Diversity of moderately halophilic bacteria associated with the soil of the black mangrove, Avicennia germinans

Abstract

Mangroves are complex ecosystems that contribute the coast environment by maintaining terrestrial and marine food chains, among others. Black mangrove, Avicennia germinans, on which this study is centered, predominates in hot climates and in soils with salinities that exceed 40 parts per thousand. An analysis of the diversity of halophilic/ halotolerant microorganisms present in the soil of these mangroves at two different localities in the southwest area of Puerto Rico, the Solar Salterns of Cabo Rojo and the Boquerón National Forest, was carried out using culture-dependent and culture-independent techniques. Soil samples from six different trees from each locality and at three different depths (0, 10 and 20cm) were processed. Analyses of isolates indicate the presence of halophilic/halotolerant microorganisms from the Proteobacteria and Firmicutes phyla. Environmental gene libraries showed that most of the clones obtained were affiliated to the Proteobacteria and Bacteroidetes phyla.