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Response of the methanogenic microbial community of a profundal lake sediment (Lake Kinneret, Israel) to algal deposition
Author(s) -
Schwarz Julia I. K.,
Eckert Werner,
Conrad Ralf
Publication year - 2008
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.2008.53.1.0113
Subject(s) - profundal zone , terminal restriction fragment length polymorphism , algae , environmental chemistry , microbial population biology , biology , methanogenesis , sediment , deltaproteobacteria , water column , botany , ecology , chemistry , bacteria , biochemistry , methane , 16s ribosomal rna , polymerase chain reaction , paleontology , genetics , gene , restriction fragment length polymorphism , gammaproteobacteria
An algal bloom of Peridinium gatunenese generally precedes the annual maximum of methane release from the profundal sediment of Lake Kinneret. Therefore, we investigated the response of the sediment methanogenic microbial community to simulated algal deposition. Addition of algal biomass on top of sediment cores resulted in increased CH 4 production rates and concentrations of the fermentation products acetate and propionate in the upper 4‐cm layers with maximum values at 1‐cm depth. Addition of algae to sediment slurries also resulted in increased CH 4 production rates and a transient increase of H 2 , propionate, and acetate concentrations within the first 10 d after addition. The composition of the active microbial community was determined by analysis of terminal restriction fragment polymorphism (T‐RFLP) targeting ribosomal RNA and cloning and sequencing of reverse‐transcribed 16S rRNA. Analysis of the sediment in the presence and absence of algae indicated that among the Bacteria , members of Deltaproteobacteria and Clostridiales responded by synthesis of ribosomes after 1 d of incubation and those of Bacteroidetes after 6 d. Among the Archaea , ribosomal RNA of the Methanosaetaceae (i.e., acetate‐utilizing methanogens) slightly increased after 6 d. Algal deposition apparently stimulated ribosomal synthesis in these sediment microorganisms, thus resulting in increased activity. We conclude that these microorganisms were involved in degradation of the algal biomass resulting in transient release of acetate and other fermentation products and increased production of CH 4 .