Seasonal variation of microbial populations and biomass in Tatachia grassland soils of Taiwan

Abstract

To investigate the seasonal variations of microbial ecology in grassland of Tatachia forest, soil properties, microbial populations, microbial biomass, and 16S rDNA clone library analysis were determined. The soil had temperatures 6.6-18.4 degrees C, pH 3.6-5.1, total organic carbon 1.11-10.68%, total nitrogen 0.18-0.78%, and C/N ratios 3.46-20.55. Each gram of dry soil contained bacteria, actinomycetes, fungi, cellulolytic, phosphate-solubilizing microbes, and nitrogen-fixing microbes 4.54 x 10(4) to 3.79 x 10(7), 3.43 x 10(2) to 2.17 x 10(5), 5.74 x 10(3) to 3.76 x 10(6), 1.97 x 10(3) to 1.34 x 10(6), 8.49 x 10(2) to 5.59 x 10(5), and 3.86 x 10(2) to 3.75 x 10(5) CFU, respectively. Each gram of soil contained 117-2,482 microg of microbial biomass carbon, 23-216 microg of microbial biomass nitrogen and 9-29 microg of DNA. The microbial populations, microbial biomass, and DNA decreased stepwise with the depth of soil, and they had low values in winter seasons. The microbial populations, microbial biomass carbon, microbial biomass nitrogen, and DNA at the BW2 horizon were 8.42-17.84, 19.26-64.40, 16.84-61.11, and 31.03-46.26% of those at the O horizon, respectively. When analyzing 16S rDNA library, members of Proteobacteria, Acidobacteria, Actinobacteria, Bacteroidetes, Chloroflexi, Firmicutes, candidate division TMI, candidate division TM7, Gammatimonadetes, and Verrucomicrobia were identified. Members of Proteobacteria (44.4%) and Acidobacteria (33.3%) dominated the clone libraries. Within the phylum Proteobacteria, alpha-, beta-, and gamma-Proteobacteria were most numerous, followed by delta-Proteobacteria.

Horizon-Specific Bacterial Community Composition of German Grassland Soils, as Revealed by Pyrosequencing-Based Analysis of 16S rRNA Genes

“…A decrease in the total microbial biomass with soil depth was previously reported (5,9,16,18). The total microbial biomass was positively correlated with the concentration of OC (r ϭ 0.88; P Ͻ 0.01).…”

Actinobacterial community dominated by a distinct clade in acidic soil of a waterlogged deciduous forest

“…Similar effects have been observed previously in relation to these and other abiotic factors, particularly an increased proportion of actinobacteria in bacterial communities at low soil moisture, low temperature, and organic matter of low quality and/or quantity (Fritze et al ., ; Fierer et al ., ; Yang et al ., ). Actinobacteria have been described as a group that follows seasonal differences; some studies have found them more frequent in a wet summer (Cho et al ., ) and others in a dry winter (Yang et al ., ). Generally, actinobacteria proliferate during periods with comparatively low temperatures (Steger et al ., ) and indeed they were found dominating in colder periods of the year (Lipson & Schmidt, ).…”

Metagenomic profiles of free-living archaea, bacteria and small eukaryotes in coastal areas of Sichang island, Thailand

“…Firmicutes could produce endospores under a hostile environment [27] like Tha Wang. Verrucomicrobia and Gammatimonadetes are new phyla that are under-represented by culture, but are believed to be common in nature, especially in soils [28]. Ternicutes refer to bacteria with no cell wall, such as Mycoplasma and Ureaplasma , that could cause human respiratory and urogenital tract diseases [27].…”