Mangroves are important and productive ecosystems found in tropical and subtropical environments, providing habitats for a variety of species. These ecosystems have been suffering from impacts through the years and consequently the activity of soil microorganisms, which are directly related to valuable processes in these environments, is affected. Understanding the diversity and function of microbial communities and their response to environmental changes is essential for the maintenance of significant functions in these ecosystems. Currently few studies in Brazil are devoted to the understanding of microbial diversity in mangrove soils. Thus it becomes essential to study the microbial diversity in these environments and to search for genes encoding for enzymes of biotechnological interest. For this reason, the aim of this study was to assess the soil microbial diversity from four mangroves in Ceara state, northeast Brazil, and its response to possible impacts, and search genes of biotechnological interest using metagenomics strategies.
The four studied mangroves are located in the state of Ceara, northeastern Brazil. Two of them are located in the extreme east (Jaguaribe Mangrove) and west (the Mangrove Timonha) coast of the state separated by 530 km and the other two are located in a central region, near the city of Fortaleza, state capital (Coco and Pacoti mangroves). Jaguaribe (JAG) mangrove is located at the largest river of the state, in a sub-urbanized region, and impacted by agriculture run-off and extensive shrimp farming. In contrast, Timonha (TIM) is an undisturbed mangrove, located in an island inside the estuary, with limited access to humans. The Cocó (COC) and Pacoti (PAC) mangroves, located in the metropolitan region of Fortaleza, suffer impacts due to water pollution, deforestation of native vegetation, especially vegetation of dunes and mangroves, extraction of sand, clay, stone and release of industrial effluents. The sampling locations TIM - S 02º56.587’ W 041º19.064’; JAG - S 04°26.749’ W 37°46.989’; PAC - S 03º49.226’ W 038º24.286’; COC - S 03°46.482’ W 38°26.552’. Sediment samples were collected in three sites inside the mangroves aiming to cover typical habitats in this ecosystems: near the river, Rhizophora mangle forest and the last one in an area covered by Avicennia schaueriana. In each habitat five sediment cores from 0-10 cm layer in an area of 10 m2, in the low tide of 0.0, were collected. The fifteen samples from each mangrove were pooled to form a single composite sample and DNA metagenomic extraction was carried out using the PowerMaxSoil DNA Extraction kit (MoBio Laboratories, Carlsbad, CA, USA) following the manufacturer's protocol. The extracted DNA was then subjected to 454 pyrosequencing.
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