Climate change effect in organic matter decay and ecological succession in mangroves

Author(s)

Juanita Hernandez Solano

• Document type: Master's Dissertation
• Press: Piracicaba.
• Institution: Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC)
• Defense date: 2017-11-06

Examining board members

Rodrigo Gouvêa Taketani; Acacio Aparecido Navarrete

• Advisor: Rodrigo Gouvêa Taketani

Abstract

Mangrove are coastal environments that provide resources for adjacent ecosystems due to its high productivity that comes from decay of organic matter and carbon cycling, made by microbial communities in sediments. Since the increase of gas release due to fossil fuel burning in the 1970\', many abnormalities have been observed such as temperature and acidification increase. Base on the hypothesis that climate change modifies microbial diversity associate to decay of organic matter in mangrove sediments, changing the emission of Greenhouse Gases (GHG) rate, the goal of this research is to evaluate the dynamics of microbial diversity under the climate change conditions during de decay process, correlating with the emission of GHG. Destructive microcosms containing organic matter from the main plant species found in mangroves throughout the State of São Paulo, Brazil (Rhizophora mangle, Laguncularia racemosa e Avicennia schaueriana) were incubate simulating climate changes (increase in temperature and pH). Sampling of decaying material (for sequencing of 16S rRNA region and quantification of the mcrA gene) and of gasses were collected for 45 days. The variation in time resulted in important increases of α diversity impacts and in the community composition, initially with greater abundancy of Gammaproteobacteria for all plant species despite of the climate conditions variations. The PCoA analysis bespeak the chronological sequence in β diversity, indicating the increase of Deltaproteobacteria at the end of the process. The GHG emission varied in function of the organic matter source and the relation between methane (CH4) release and the presence of the mcrA gene in two of the plant species studied, if the increase in the Deltaproteobacteria population controlled its emission. Despite the great number of studies about the decay of organic matter and emission of gases in mangroves, few present an approach like this work, which aims to understand the relation between these three processes and the climate changes, a pressing problem nowadays. (AU)

• FAPESP's process: 15/23102-9 - Effect of Climate changes on the organic matter decomposition and ecological succession in mangroves
• Grantee: Juanita Hernández Solano
• Support Opportunities: Scholarships in Brazil - Master