scholarly journals Molecular characterization of estuarine bacterial communities that use high- and low-molecular weight fractions of dissolved organic carbon

2001 ◽  
Vol 25 ◽  
pp. 127-139 ◽  
Author(s):  
JS Covert ◽  
MA Moran
Keyword(s):  
Molecular Weight ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Molecular Characterization ◽  
Bacterial Communities ◽  
Low Molecular Weight ◽  
Molecular Weight Fractions

Molecular Characterization of Low-Molecular-Weight Component Protein, Flp, inActinobacillus actinomycetemcomitansFimbriae

1998 ◽  
Vol 42 (4) ◽  
pp. 253-258 ◽  
Author(s):  
Tetsuyoshi Inoue ◽  
Ichiro Tanimoto ◽  
Hiroyuki Ohta ◽  
Keijiro Kato ◽  
Yoji Murayama ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Molecular Characterization ◽  
Low Molecular Weight ◽  
Component Protein

scholarly journals Characterization of bacterioplankton communities and quantification of organic carbon pools off the Galapagos Archipelago under contrasting environmental conditions

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5984 ◽  
Author(s):  
Nataly Carolina Guevara Campoverde ◽  
Christiane Hassenrück ◽  
Pier Luigi Buttigieg ◽  
Astrid Gärdes
Keyword(s):  
Organic Carbon ◽  
Carbon Cycle ◽  
Dissolved Organic Carbon ◽  
Bacterial Communities ◽  
Carbon Pools ◽  
Aggregate Formation ◽  
Galapagos Archipelago ◽  
Carbon Concentrations ◽  
Bacterioplankton Communities

Bacteria play a crucial role in the marine carbon cycle, contributing to the production and degradation of organic carbon. Here, we investigated organic carbon pools, aggregate formation, and bacterioplankton communities in three contrasting oceanographic settings in the Galapagos Archipelago. We studied a submarine CO2 vent at Roca Redonda (RoR), an upwelling site at Bolivar Channel (BoC) subjected to a weak El Niño event at the time of sampling in October 2014, as well as a site without volcanic or upwelling influence at Cowley Islet (CoI). We recorded physico-chemical parameters, and quantified particulate and dissolved organic carbon, transparent exopolymeric particles, and the potential of the water to form larger marine aggregates. Free-living and particle-attached bacterial communities were assessed via 16S rRNA gene sequencing. Both RoR and BoC exhibited temperatures elevated by 1–1.5 °C compared to CoI. RoR further experienced reduced pH between 6.8 and 7.4. We observed pronounced differences in organic carbon pools at each of the three sites, with highest dissolved organic carbon concentrations at BoC and RoR, and highest particulate organic carbon concentrations and aggregate formation at BoC. Bacterioplankton communities at BoC were dominated by opportunistic copiotrophic taxa, such as Alteromonas and Roseobacter, known to thrive in phytoplankton blooms, as opposed to oligotrophic taxa dominating at CoI, such as members of the SAR11 clade. Therefore, we propose that bacterial communities were mainly influenced by the availability of organic carbon at the investigated sites. Our study provides a comprehensive characterization of organic carbon pools and bacterioplankton communities, highlighting the high heterogeneity of various components of the marine carbon cycle around the Galapagos Archipelago.

Structural influences of low-molecular-weight dissolved organic carbon mimics on the photolytic fate of atrazine

1998 ◽  
Vol 17 (6) ◽  
pp. 975-981 ◽  
Author(s):  
Cathleen J. Hapeman ◽  
Susanna Bilboulian ◽  
Brent G. Anderson ◽  
Alba Torrents
Keyword(s):  
Molecular Weight ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Low Molecular Weight

scholarly journals Lack of Correlation between Turnover of Low-Molecular-Weight Dissolved Organic Carbon and Differences in Microbial Community Composition or Growth across a Soil pH Gradient

2011 ◽  
Vol 77 (8) ◽  
pp. 2791-2795 ◽  
Author(s):  
Johannes Rousk ◽  
Philip C. Brookes ◽  
Helen C. Glanville ◽  
David L. Jones
Keyword(s):  
Molecular Weight ◽  
Microbial Community ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Community Composition ◽  
Soil Ph ◽  
Predictive Power ◽  
Microbial Community Composition ◽  
Low Molecular Weight ◽  
Soil C

ABSTRACTWe studied how soil pH (pHs 4 to 8) influenced the mineralization of low-molecular-weight (LMW)-dissolved organic carbon (DOC) compounds, and how this compared with differences in microbial community structure. The mineralization of LMW-DOC compounds was not systematically connected to differences in soil pH, consistent with soil respiration. In contrast, the microbial community compositions differed dramatically. This suggests that microbial community composition data will be of limited use in improving the predictive power of soil C models.

scholarly journals Identification and analysis of low-molecular-weight dissolved organic carbon in subglacial basal ice ecosystems by ion chromatography

2016 ◽  
Vol 13 (12) ◽  
pp. 3833-3846 ◽  
Author(s):  
Emily C. O'Donnell ◽  
Jemma L. Wadham ◽  
Grzegorz P. Lis ◽  
Martyn Tranter ◽  
Amy E. Pickard ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Microbial Activity ◽  
Free Amino ◽  
Low Molecular Weight ◽  
Subglacial Environment ◽  
Basal Ice ◽  
Order Of Magnitude

Abstract. Determining the concentration and composition of dissolved organic carbon (DOC) in glacial ecosystems is important for assessments of in situ microbial activity and contributions to wider biogeochemical cycles. Nonetheless, there is limited knowledge of the abundance and character of DOC in basal ice and the subglacial environment and a lack of quantitative data on low-molecular-weight (LMW) DOC components, which are believed to be highly bioavailable to microorganisms. We investigated the abundance and composition of DOC in basal ice via a molecular-level DOC analysis. Spectrofluorometry and a novel ion chromatographic method, which has been little utilized in glacial science for LMW-DOC determinations, were employed to identify and quantify the major LMW fractions (free amino acids, carbohydrates, and carboxylic acids) in basal ice from four glaciers, each with a different type of overridden material (i.e. the pre-entrainment sedimentary type such as lacustrine material or palaeosols). Basal ice from Joyce Glacier (Antarctica) was unique in that 98 % of the LMW-DOC was derived from the extremely diverse free amino acid (FAA) pool, comprising 14 FAAs. LMW-DOC concentrations in basal ice were dependent on the bioavailability of the overridden organic carbon (OC), which in turn was influenced by the type of overridden material. Mean LMW-DOC concentrations in basal ice from Russell Glacier (Greenland), Finsterwalderbreen (Svalbard), and Engabreen (Norway) were low (0–417 nM C), attributed to the relatively refractory nature of the OC in the overridden palaeosols and bedrock. In contrast, mean LMW-DOC concentrations were an order of magnitude higher (4430 nM C) in basal ice from Joyce Glacier, a reflection of the high bioavailability of the overridden lacustrine material (> 17 % of the sediment OC comprised extractable carbohydrates, a proxy for bioavailable OC). We find that the overridden material may act as a direct (via abiotic leaching) and indirect (via microbial cycling) source of DOC to the subglacial environment and provides a range of LMW-DOC compounds that may stimulate microbial activity in wet subglacial sediments.

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