scholarly journals Signature lipid biomarkers for in situ microbial biomass, community structure and nutritional status of deep subsurface microbiota in relation to geochemical gradients. Final technical report

1998 ◽  
Author(s):  
D.C. White ◽  
D.B. Ringelberg
Keyword(s):  
Community Structure ◽  
Microbial Biomass ◽  
Nutritional Status ◽  
Lipid Biomarkers ◽  
Deep Subsurface ◽  
Technical Report

In situ measurement of microbial biomass, community structure and nutritional status

1993 ◽  
Vol 344 (1670) ◽  
pp. 59-67 ◽  
Keyword(s):  
Fatty Acids ◽  
Community Structure ◽  
Microbial Biomass ◽  
Nutritional Status ◽  
Metabolic Activity ◽  
Total Phospholipid ◽  
Quantitative Measure ◽  
Essential Component ◽  
Quantitative Definition

In sediments and soils the extant microbiota that can be counted by direct microscopy have proved exceedingly difficult to isolate and culture. Classical tests are time consuming and provide little indication of the interactions within the community, the community nutritional status or metabolic activity. The in situ method is based on the extraction of ‘signature’ lipid biomarkers (SLB) from the cell membranes and walls of microorganisms. Lipids are cellular components that are recoverable by extraction with organic solvents. Lipids are an essential component of the membrane of all cells and play a role as storage materials. Extraction of the lipid components of the microbiota from soils and sediments provides both purification and concentration together with an in situ quantitative analysis of the microbial biomass, community structure, and nutritional status. The determination of the total phospholipid ester-linked fatty acids (PLFA) provides a quantitative measure of the viable biomass. Viable microbes have an intact membrane which contains phospholipids (and PLFA). With cell death enzymes hydrolyze the phosphate group within minutes to hours. The lipid core remains as diglyceride (DG). The resulting DG has the same signature fatty acids as the phospholipids (until it degrades) so a comparison of the ratio of PLFA to DG provides an indication of the viable and nonviable microbes. Analysis by SLB technique provides a quantitative definition of the microbial community structure as specific groups of microbes contain characteristic PLFA patterns. The analysis of other lipids such as the sterols (for the microeukaryotes -nematodes, algae, protozoa), glycolipids (for the phototrophs, gram-positive bacteria), or the hydroxy fatty acids in the lipopolysaccharide of the lipid A (gramnegative bacteria) can provide more detailed community structure analysis. The formation of poly (3-hydroxyalkanoic acid (PHA) in bacteria or triglyceride (TG) in the microeukaryotes relative to the PLFA provides a measure of the nutritional status. Bacteria grown with adequate carbon and terminal electron acceptors form PHA when they cannot divide, because some essential component is missing. Rates of incorporation of 14 C-acetate into PHA relative to PLFA is a sensitive indicator of disturbance artifacts in estimates of metabolic activity in sediments with redox gradients. Exposure to toxic environments can lead to minicell formation and increases in specific PLFAS. Respiratory quinone structure indicates the proportions of aerobic/anaerobic activities in the community. The SLB technology provides quantitative in situ information that define the microbial ecology in sedimentary geochemical processes.

Deep Subsurface Microbial Biomass and Community Structure in Witwatersrand Basin Mines

2006 ◽  
Vol 23 (6) ◽  
pp. 431-442 ◽  
Author(s):  
Susan M. Pfiffner ◽  
James M. Cantu ◽  
Amanda Smithgall ◽  
Aaron D. Peacock ◽  
David C. White ◽  
...  
Keyword(s):  
Community Structure ◽  
Microbial Biomass ◽  
Deep Subsurface ◽  
Witwatersrand Basin

scholarly journals Rock Surface Fungi in Deep Continental Biosphere—Exploration of Microbial Community Formation with Subsurface In Situ Biofilm Trap

2020 ◽  
Vol 9 (1) ◽  
pp. 64
Author(s):  
Maija Nuppunen-Puputti ◽  
Riikka Kietäväinen ◽  
Lotta Purkamo ◽  
Pauliina Rajala ◽  
Merja Itävaara ◽  
...  
Keyword(s):  
Significant Proportion ◽  
Debaryomyces Hansenii ◽  
Fungal Communities ◽  
Fungal Colonization ◽  
Rock Surface ◽  
Mica Schist ◽  
Deep Subsurface ◽  
Bacterial Phyla ◽  
In Situ Conditions

Fungi have an important role in nutrient cycling in most ecosystems on Earth, yet their ecology and functionality in deep continental subsurface remain unknown. Here, we report the first observations of active fungal colonization of mica schist in the deep continental biosphere and the ability of deep subsurface fungi to attach to rock surfaces under in situ conditions in groundwater at 500 and 967 m depth in Precambrian bedrock. We present an in situ subsurface biofilm trap, designed to reveal sessile microbial communities on rock surface in deep continental groundwater, using Outokumpu Deep Drill Hole, in eastern Finland, as a test site. The observed fungal phyla in Outokumpu subsurface were Basidiomycota, Ascomycota, and Mortierellomycota. In addition, significant proportion of the community represented unclassified Fungi. Sessile fungal communities on mica schist surfaces differed from the planktic fungal communities. The main bacterial phyla were Firmicutes, Proteobacteria, and Actinobacteriota. Biofilm formation on rock surfaces is a slow process and our results indicate that fungal and bacterial communities dominate the early surface attachment process, when pristine mineral surfaces are exposed to deep subsurface ecosystems. Various fungi showed statistically significant cross-kingdom correlation with both thiosulfate and sulfate reducing bacteria, e.g., SRB2 with fungi Debaryomyces hansenii.

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