scholarly journals Direct Visualization of Individual Aromatic Compound Structures in Low Molecular Weight Marine Dissolved Organic Carbon

2018 ◽  
Vol 45 (11) ◽  
pp. 5590-5598 ◽  
Author(s):  
Shadi Fatayer ◽  
Alysha I. Coppola ◽  
Fabian Schulz ◽  
Brett D. Walker ◽  
Taylor A. Broek ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Aromatic Compound ◽  
Low Molecular Weight ◽  
Direct Visualization

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.

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

2015 ◽  
Vol 12 (16) ◽  
pp. 14139-14174
Author(s):  
E. C. Lawson ◽  
J. L. Wadham ◽  
G. P. Lis ◽  
M. Tranter ◽  
A. E. Pickard ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Low Molecular Weight ◽  
Subglacial Environment ◽  
Basal Ice ◽  
Glacial Runoff ◽  
Order Of Magnitude ◽  
High Bioavailability ◽  
Subglacial Environments

Abstract. Glacial runoff is an important source of dissolved organic carbon (DOC) for downstream heterotrophic activity, despite the low overall DOC concentrations. This is because of the abundance of bioavailable, low molecular weight (LMW) DOC species. However, the provenance and character of LMW-DOC is not fully understood. We investigated the abundance and composition of DOC in subglacial environments via a molecular level DOC analysis of basal ice, which forms by water/sediment freeze-on to the glacier sole. Spectrofluorometry and a novel ion chromatographic method, which has been little utilised 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 basal debris type. Basal ice from Joyce Glacier (Antarctica) was unique in that 98 % of the LMW-DOC was derived from the extremely diverse 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 paleosols 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 sediments in current subglacial environments.

Production of dissolved organic carbon and low-molecular weight organic acids in soil solution driven by recent tree photosynthate

2007 ◽  
Vol 84 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Reiner Giesler ◽  
Mona N. Högberg ◽  
Bjarne W. Strobel ◽  
Andreas Richter ◽  
Anders Nordgren ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Organic Acids ◽  
Soil Solution ◽  
Low Molecular Weight
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