Biodiversity and functional activities of microorganisms from mangrove of the State of São Paulo

Abstract

Mangrove communities are recognized as highly productive ecosystems that provide large quantities of organic matter to adjacent coastal waters in the form of detritus. The detritus serves as a nutrient source and is the base of an extensive food web in which organisms of commercial importance take part. The collective term mangrove designates an interdital wetland ecosystem formed by a very special association of plants and animals, fungi, bacteria, microalgae, invertebrates etc, which proliferate luxuriantly in the coastal areas and rivers estuaries. Mangrove ecosystems cover roughly 60 - 75% of the world's tropical and subtropical coastlines. Brazil, Indonesia, and Australia have the greatest abundance of mangrove. These wetland ecosystems are among the most productive and diverse in the world and more than 80% of marine catches are directly or indirectly dependent on mangrove and other coastal ecosystems worldwide. There is evidence to propose a close microbe-nutrient-plant relationship that functions as a mechanism to recycle and conserve nutrients in the mangrove ecosystem. Although mangrove ecosystems are rich in organic matter, in general they are nutrient-deficient, especially of nitrogen and phosphorus. In spite of this, mangroves are highly productive. This paradox may be explained by a very efficient nutrient recycling system in which scarce essential nutrients are retained and new nutrients are regenerated from decomposing mangrove leaves. Microbial activity is responsible for major nutrient transformations within a mangrove ecosystem. In tropical mangroves, bacteria and fungi constitute 91% of the total microbial biomas, whereas algae and protozoa represent only 7% and 2%. Despite numerous studies on biogeography, botany, zoology and economic impact, little is known about the biodiversity and activities of microbes in mangrove waters, sediments and rhizosphere. Microorganisms from mangroves open up new areas of biotechnological exploitations, which drive the necessity to isolate and culture these organisms. The biochemical versatility and diversity of rare microorganisms represent an enormous variety of genes that are still unknown. More and more useful gene functions are being discovered, particularly for environmental remediation and industrial processes. Thus, this project proposes: to study the biological diversity of microorganisms from sediments, rhizosphere and endophytes of red mangrove (considering both number of species and the partition of abundance)... (AU)