scholarly journals Microbial Population Changes during Bioremediation of an Experimental Oil Spill

1999 ◽  
Vol 65 (8) ◽  
pp. 3566-3574 ◽  
Author(s):  
Sarah J. MacNaughton ◽  
John R. Stephen ◽  
Albert D. Venosa ◽  
Gregory A. Davis ◽  
Yun-Juan Chang ◽  
...  

ABSTRACT Three crude oil bioremediation techniques were applied in a randomized block field experiment simulating a coastal oil spill. Four treatments (no oil control, oil alone, oil plus nutrients, and oil plus nutrients plus an indigenous inoculum) were applied. In situ microbial community structures were monitored by phospholipid fatty acid (PLFA) analysis and 16S rDNA PCR-denaturing gradient gel electrophoresis (DGGE) to (i) identify the bacterial community members responsible for the decontamination of the site and (ii) define an end point for the removal of the hydrocarbon substrate. The results of PLFA analysis demonstrated a community shift in all plots from primarily eukaryotic biomass to gram-negative bacterial biomass with time. PLFA profiles from the oiled plots suggested increased gram-negative biomass and adaptation to metabolic stress compared to unoiled controls. DGGE analysis of untreated control plots revealed a simple, dynamic dominant population structure throughout the experiment. This banding pattern disappeared in all oiled plots, indicating that the structure and diversity of the dominant bacterial community changed substantially. No consistent differences were detected between nutrient-amended and indigenous inoculum-treated plots, but both differed from the oil-only plots. Prominent bands were excised for sequence analysis and indicated that oil treatment encouraged the growth of gram-negative microorganisms within the α-proteobacteria andFlexibacter-Cytophaga-Bacteroides phylum. α-Proteobacteria were never detected in unoiled controls. PLFA analysis indicated that by week 14 the microbial community structures of the oiled plots were becoming similar to those of the unoiled controls from the same time point, but DGGE analysis suggested that major differences in the bacterial communities remained.

2008 ◽  
Vol 74 (10) ◽  
pp. 3014-3021 ◽  
Author(s):  
Robert H. Findlay ◽  
Christine Yeates ◽  
Meredith A. J. Hullar ◽  
David A. Stahl ◽  
Louis A. Kaplan

ABSTRACT A field study was conducted to determine the microbial community structures of streambed sediments across diverse geographic and climatic areas. Sediment samples were collected from three adjacent headwater forest streams within three biomes, eastern deciduous (Pennsylvania), southeastern coniferous (New Jersey), and tropical evergreen (Guanacaste, Costa Rica), to assess whether there is biome control of stream microbial community structure. Bacterial abundance, microbial biomass, and bacterial and microbial community structures were determined using classical, biochemical, and molecular methods. Microbial biomass, determined using phospholipid phosphate, was significantly greater in the southeastern coniferous biome, likely due to the smaller grain size, higher organic content, and lower levels of physical disturbance of these sediments. Microbial community structure was determined using phospholipid fatty acid (PLFA) profiles and bacterial community structure from terminal restriction fragment length polymorphism and edited (microeukaryotic PLFAs removed) PLFA profiles. Principal component analysis (PCA) was used to investigate patterns in total microbial community structure. The first principal component separated streams based on the importance of phototrophic microeukaryotes within the community, while the second separated southeastern coniferous streams from all others based on increased abundance of fungal PLFAs. PCA also indicated that within- and among-stream variations were small for tropical evergreen streams and large for southeastern coniferous streams. A similar analysis of bacterial community structure indicated that streams within biomes had similar community structures, while each biome possessed a unique streambed community, indicating strong within-biome control of stream bacterial community structure.


2012 ◽  
Vol 92 (3) ◽  
pp. 543-549 ◽  
Author(s):  
Liang Mi ◽  
Guanghua Wang ◽  
Jian Jin ◽  
Yueyu Sui ◽  
Judong Liu ◽  
...  

Mi, L., Wang, G., Jin, J., Sui, Y., Liu, J. and Liu, X. 2012. Comparison of microbial community structures in four Black soils along a climatic gradient in northeast China. Can. J. Soil Sci. 92: 543–549. Surveys of microorganisms across climatic gradients provide important information about their biodiversity and spatial distribution, which is linked to fundamental ecological functions. The present study investigated the bacterial communities, including total and culturable communities, and fungal communities in Black soils collected from Lishu (lat. 43°20′N, long. 124°28′E), Dehui (lat. 44°12′N, long. 125°33′E), Hailun (lat. 47°26′N, long. 126°38′E) and Beian (lat. 48°17′N, long. 127°15′E) in northeast China. Bacterial and fungal communities were evaluated by polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE) banding patterns of partial 16S rDNA and fungal rDNA internal transcribed spacer regions (ITS), respectively. Bacterial and fungal diversity, based on the number of DGGE bands, were similar among the locations, but cluster analysis of banding patterns showed distinct microbial communities along the climatic gradient. A closer relationship was found among soil bacterial (total and culturable) and fungal communities in neighboring locations than those at greater distance, which suggested that the spatial distribution of microbial community existed in the Black Soil Zone. Comparison of DGGE profiles among the four locations showed that the changes of fungal community and culturable bacterial community were greater than that of bacterial community, suggesting that fungal community and culturable bacterial community are more suitable to study microbial biogeographic distribution in Black soils.


1999 ◽  
Vol 65 (12) ◽  
pp. 5403-5408 ◽  
Author(s):  
Jessica R. Hanson ◽  
Jennifer L. Macalady ◽  
David Harris ◽  
Kate M. Scow

ABSTRACT Phospholipid fatty acid (PLFA) analysis of a soil microbial community was coupled with 13C isotope tracer analysis to measure the community’s response to addition of 35 μg of [13C]toluene ml of soil solution−1. After 119 h of incubation with toluene, 96% of the incorporated13C was detected in only 16 of the total 59 PLFAs (27%) extracted from the soil. Of the total 13C-enriched PLFAs, 85% were identical to the PLFAs contained in a toluene-metabolizing bacterium isolated from the same soil. In contrast, the majority of the soil PLFAs (91%) became labeled when the same soil was incubated with [13C]glucose. Our study showed that coupling13C tracer analysis with PLFA analysis is an effective technique for distinguishing a specific microbial population involved in metabolism of a labeled substrate in complex environments such as soil.


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