Dynamics of the Methanogenic Archaea in Tropical Estuarine Sediments

Abstract

Methanogenesis may represent a key process in the terminal phases of anaerobic organic matter mineralization in sediments of coastal lagoons. The aim of the present work was to study the temporal and spatial dynamics of methanogenic archaea in sediments of tropical coastal lagoons and their relationship with environmental changes in order to determine how these influence methanogenic community. Sediment samples were collected during the dry (February, May, and early June) and rainy seasons (July, October, and November). Microbiological analysis included the quantification of viable methanogenic archaea (MA) with three substrates and the evaluation of kinetic activity from acetate in the presence and absence of sulfate. The environmental variables assessed were temperature, pH, Eh, salinity, sulfate, solids content, organic carbon, and carbohydrates. MA abundance was significantly higher in the rainy season (106–107 cells/g) compared with the dry season (104–106 cells/g), with methanol as an important substrate. At spatial level, MA were detected in the two layers analyzed, and no important variations were observed either in MA abundance or activity. Salinity, sulfate, solids, organic carbon, and Eh were the environmental variables related to methanogenic community. A conceptual model is proposed to explain the dynamics of the MA.

Anaerobic microbiota: spatial-temporal changes in the sediment of a tropical coastal lagoon with ephemeral inlet

“…It has been established that 30 -40 % of the methane generated in sediments is formed from hydrogen that is used by Methanobacterium and Methanobrevibacter (Conrad, 1999), whereas acetate generates approximately two thirds of the methane that may be used by the genera Methanosarcina and Methanococcoides. Increases in MA during the rainy season have been reported for other tropical lagoon systems (Preston & Prodduturu, 1992;Torres et al, 2013).…”

Factors influencing spatio-temporal variation of methane and nitrous oxide emission from a tropical mangrove of eastern coast of India

“…However, the microbial studies conducted over Indian mangrove ecosystem dealt mainly with structural aspect instead of their functional implications (Kathiresan and Selvam, 2006;Ramanthan et al, 2008;Thatoi et al, 2012;Torres-Alvarado et al, 2013). Again, a comprehensive study on the relationship of microbial population with CH 4 and N 2 O emission from the mangrove sediment over wide range of seasonal variation is limited.…”

Assessment of Total Mercury (HgT) in Sediments and Biota of Indian Sundarban Wetland and Adjacent Coastal Regions

“…According to Liao (1990), the low pH in sediments could be partly resulting from oxidation of FeS 2 and FeS to sulfate (SO 4 2− ) and partly from the mangrove litter decomposition and hydrolysis of tannin in mangrove plants releasing various organic acids. Lower pH values have also been reported in sediment samples from tropical wetland sites (Torres-Alvarado et al, 2013, Peck et al, 2002. The sediment samples exhibited low values of organic carbon (0.34 to 1.08%).…”