scholarly journals Genotypic and Phenotypic Responses of a Riverine Microbial Community to Polycyclic Aromatic Hydrocarbon Contamination

1998 ◽  
Vol 64 (9) ◽  
pp. 3422-3428 ◽  
Author(s):  
Donald E. Langworthy ◽  
Raymond D. Stapleton ◽  
Gary S. Sayler ◽  
Robert H. Findlay
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Nucleic Acid ◽  
Microbial Community Structure ◽  
Phospholipid Fatty Acid ◽  
Principal Component ◽  
Dry Weight ◽  
Hydrocarbon Contamination ◽  
Polycyclic Aromatic ◽  
Nucleic Acid Analysis

ABSTRACT The phenotypic and genotypic adaptation of a freshwater sedimentary microbial community to elevated (22 to 217 μg g [dry weight] of sediment−1) levels of polycyclic aromatic hydrocarbons (PAHs) was determined by using an integrated biomolecular approach. Central to the approach was the use of phospholipid fatty acid (PLFA) profiles to characterize the microbial community structure and nucleic acid analysis to quantify the frequency of degradative genes. The study site was the Little Scioto River, a highly impacted, channelized riverine system located in central Ohio. This study site is a unique lotic system, with all sampling stations having similar flow and sediment characteristics both upstream and downstream from the source of contamination. These characteristics allowed for the specific analysis of PAH impact on the microbial community. PAH concentrations in impacted sediments ranged from 22 to 217 μg g (dry weight) of sediment−1, while PAH concentrations in ambient sediments ranged from below detection levels to 1.5 μg g (dry weight) of sediment−1. Total microbial biomass measured by phospholipid phosphate (PLP) analysis ranged from 95 to 345 nmol of PLP g (dry weight) of sediment−1. Nucleic acid analysis showed the presence of PAH-degradative genes at all sites, although observed frequencies were typically higher at contaminated sites. Principal component analysis of PLFA profiles indicated that moderate to high PAH concentrations altered microbial community structure and that seasonal changes were comparable in magnitude to the effects of PAH pollution. These data indicate that this community responded to PAH contamination at both the phenotypic and the genotypic level.

scholarly journals Biome-Level Biogeography of Streambed Microbiota

2008 ◽  
Vol 74 (10) ◽  
pp. 3014-3021 ◽  
Author(s):  
Robert H. Findlay ◽  
Christine Yeates ◽  
Meredith A. J. Hullar ◽  
David A. Stahl ◽  
Louis A. Kaplan
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Microbial Biomass ◽  
Bacterial Community ◽  
Microbial Community Structure ◽  
Bacterial Community Structure ◽  
Phospholipid Fatty Acid ◽  
Principal Component ◽  
Community Structures ◽  
Microbial Community Structures

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.

scholarly journals Direct and Indirect Influence of Parental Bedrock on Streambed Microbial Community Structure in Forested Streams

2011 ◽  
Vol 77 (21) ◽  
pp. 7681-7688 ◽  
Author(s):  
Jennifer J. Mosher ◽  
Robert H. Findlay
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Microbial Community Structure ◽  
Chemical Nature ◽  
Stream Water ◽  
Phospholipid Fatty Acid ◽  
Fatty Acid Analysis ◽  
Chemical Parameters ◽  
Physical And Chemical ◽  
Benthic Microbial Communities

ABSTRACTA correlative study was performed to determine if variation in streambed microbial community structure in low-order forested streams can be directly or indirectly linked to the chemical nature of the parental bedrock of the environments through which the streams flow. Total microbial and photosynthetic biomass (phospholipid phosphate [PLP] and chlorophylla), community structure (phospholipid fatty acid analysis), and physical and chemical parameters were measured in six streams, three located in sandstone and three in limestone regions of the Bankhead National Forest in northern Alabama. Although stream water flowing through the two different bedrock types differed significantly in chemical composition, there were no significant differences in total microbial and photosynthetic biomass in the sediments. In contrast, sedimentary microbial community structure differed between the bedrock types and was significantly correlated with stream water ion concentrations. A pattern of seasonal variation in microbial community structure was also observed. Further statistical analysis indicated dissolved organic matter (DOM) quality, which was previously shown to be influenced by geological variation, correlated with variation in bacterial community structure. These results indicate that the geology of underlying bedrock influences benthic microbial communities directly via changes in water chemistry and also indirectly via stream water DOM quality.

scholarly journals Soil Microbial Community Structure and Target Organisms under Different Fumigation Treatments

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Sadikshya R. Dangi ◽  
James S. Gerik ◽  
Rebecca Tirado-Corbalá ◽  
Husein Ajwa
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Microbial Community Structure ◽  
Methyl Bromide ◽  
Soil Microorganisms ◽  
Phospholipid Fatty Acid ◽  
Natural Soil ◽  
Soil Microbial Community Structure ◽  
Soil Microbial ◽  
Field Samples

Producers of several high-value crops in California rely heavily on soil fumigants to control key diseases, nematodes, and weeds. Fumigants with broad biocidal activity can affect both target and nontarget soil microorganisms. The ability of nontarget soil microorganisms to recover after fumigation treatment is critical because they play an important role in sustaining the health of agricultural and natural soil systems. Fumigation trial was conducted in Parlier, CA, and the study focuses on the effects of different rates of Telone C35 and also methyl bromide fumigation with polyethylene (PE) and totally impermeable film (TIF) tarps on target and nontarget soil microorganisms using field samples. Results indicated that the populations of target organisms, such asFusarium oxysporumandPythiumspp., were reduced at all rates of fumigants. Phospholipid fatty acid (PLFA) analysis indicated that all major nontarget soil microbial groups such as Gram positive bacteria, Gram negative bacteria, fungi, and arbuscular mycorrhizal fungi (AMF) were affected by methyl bromide (MeBr) fumigation treatment. In general, the effects of Telone C35 (299 L/ha) under PE tarp had the least impact on microbial community structure and better effect on controlling target microorganisms and, therefore, indicated the better option among fumigation treatments.

Soil Microbial Community Structure in Tree Peony (Paeonia suffruticosa) Garden Based on PLFA Analysis

2014 ◽  
Vol 675-677 ◽  
pp. 82-85
Author(s):  
Dong Xue ◽  
Xiang Dong Huang ◽  
Lian Xue
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Microbial Community Structure ◽  
Soil Microbial Community ◽  
Phospholipid Fatty Acid ◽  
Shannon Index ◽  
Tree Peony ◽  
Soil Microbial Community Structure ◽  
Soil Microbial ◽  
Chronological Change

Understanding the chronological change in soil microbial community structure of tree peony garden ecosystem is important from ecological, environmental, and management perspectives. Soil samples were collected from three tree peony garden systems (5-, 12-, and 25-year-old tree peony gardens), and adjacent wasteland at Luoyang, Henan Province of China. Soil microbial community structure was analyzed by phospholipid fatty acid (PLFA) method. The bacterial and actinomycete PLFAs increased from the wasteland to 5-year-old tree peony garden and then decreased from the 5- to 25-year-old tree peony garden, and the fungal PLFA first increased and then decreased with the increasing planting years, with the greatest amount found in the 12-year-old tree peony garden. The conversion from the wasteland to tree peony garden resulted in a significant increase in Shannon index, Richness, and Evenness. However, with the succeeding development of tree peony garden ecosystems, Shannon index, Richness, and Evenness decreased from the 5- to 25-year-old tree peony garden.

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