Dissolved organic matter (DOM) and base-extracted particulate organic matter (BEPOM) collected from a plankton senescence experiment from water samples offshore of North Carolina

2019 ◽  
Author(s):  
Chris Osburn ◽  
Thomas Bianchi ◽  
Astrid Schnetzer ◽  
Kai Ziervogel
Keyword(s):  
North Carolina ◽  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Particulate Organic Matter ◽  
Water Samples

scholarly journals Sink or link? The bacterial role in benthic carbon cycling in the Arabian Sea's oxygen minimum zone

2013 ◽  
Vol 10 (11) ◽  
pp. 6879-6891 ◽  
Author(s):  
L. Pozzato ◽  
D. Van Oevelen ◽  
L. Moodley ◽  
K. Soetaert ◽  
J. J. Middelburg
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Particulate Organic Matter ◽  
Experimental Period ◽  
Oxygen Minimum Zone ◽  
Trophic Levels ◽  
Isotope Tracer ◽  
Oxygen Conditions ◽  
Minimum Zone ◽  
Oxygen Minimum

Abstract. The bacterial loop, the consumption of dissolved organic matter (DOM) by bacteria and subsequent transfer of bacterial carbon to higher trophic levels, plays a prominent role in pelagic food webs. However, its role in sedimentary ecosystems is not well documented. Here we present the results of isotope tracer experiments performed under in situ oxygen conditions in sediments from inside and outside the Arabian Sea's oxygen minimum zone (OMZ) to study the importance of the microbial loop in this setting. Particulate organic matter, added as phytodetritus, was processed by bacteria, protozoa and metazoans, while dissolved organic matter was processed only by bacteria and there was very little, if any, transfer to higher trophic levels within the 7 day experimental period. This lack of significant transfer of bacterial-derived carbon to metazoan consumers indicates that the bacterial loop is rather inefficient, in sediments both inside and outside the OMZ. Moreover, metazoans directly consumed labile particulate organic matter resources and thus competed with bacteria for phytodetritus.

Chromophoric Dissolved Organic Matter (CDOM) In Rainwater, Southeastern North Carolina, USA

2006 ◽  
Vol 54 (1) ◽  
pp. 21-41 ◽  
Author(s):  
Robert J. Kieber ◽  
Robert F. Whitehead ◽  
Seth N. Reid ◽  
Joan D. Willey ◽  
Pamela J. Seaton
Keyword(s):  
North Carolina ◽  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Chromophoric Dissolved Organic Matter

scholarly journals Fast-freezing with liquid nitrogen preserves bulk dissolved organic matter concentrations, but not its composition

2016 ◽  
Author(s):  
Lisa Thieme ◽  
Daniel Graeber ◽  
Martin Kaupenjohann ◽  
Jan Siemens
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Liquid Nitrogen ◽  
Water Samples ◽  
Terrestrial Ecosystems ◽  
Spectroscopic Properties ◽  
Fluorescence Excitation ◽  
Total Fluorescence ◽  
Fluorescence Excitation Emission Matrices ◽  
Fast Freezing

Abstract. Freezing can affect concentrations and spectroscopic properties of dissolved organic matter (DOM) in water samples. Nevertheless, water samples are regularly frozen for sample preservation. In this study we tested the effect of different freezing methods (standard freezing at −18 °C and fast-freezing with liquid nitrogen) on DOM concentrations measured as organic carbon (DOC) concentrations and on spectroscopic properties of DOM from different terrestrial ecosystems (forest and grassland). Fresh and differently frozen throughfall, stemflow and soil solution samples were analyzed for DOC concentrations, UV-vis absorption and fluorescence excitation-emission matrices combined with parallel factor analysis (PARAFAC). Fast-freezing with liquid nitrogen prevented a significant decrease of DOC concentrations observed after freezing at −18 °C. Nonetheless, the share of PARAFAC components 1 (EXmax < 250 nm (340 nm), EMmax: 480 nm) and 2 (EXmax: 335 nm, EMmax: 408 nm) to total fluorescence and the humification index (HIX) decreased after both freezing treatments, while the shares of component 3 (EXmax: < 250 nm (305 nm), EMmax: 438 nm) as well as SUVA254 increased. The contribution of PARAFAC component 4 (EXmax: 280 nm, EMmax: 328 nm) to total fluorescence was not affected by freezing. We recommend fast-freezing with liquid nitrogen for preservation of bulk DOC concentrations of samples from terrestrial sources, whereas immediate measuring is preferable to preserve spectroscopic properties of DOM.

scholarly journals Spatial and seasonal variations in the composition of dissolved organic matter in a tropical catchment: the Lower Kinabatangan River, Sabah, Malaysia

2016 ◽  
Vol 18 (1) ◽  
pp. 137-150 ◽  
Author(s):  
Sahana Harun ◽  
Andy Baker ◽  
Chris Bradley ◽  
Gilles Pinay
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Seasonal Variations ◽  
Water Samples ◽  
River Catchment ◽  
Lower Kinabatangan

Dissolved organic matter (DOM) was characterised in water samples sampled in the Lower Kinabatangan River Catchment, Sabah, Malaysia between October 2009 and May 2010.

scholarly journals Fast-freezing with liquid nitrogen preserves bulk dissolved organic matter concentrations, but not its composition

2016 ◽  
Vol 13 (16) ◽  
pp. 4697-4705 ◽  
Author(s):  
Lisa Thieme ◽  
Daniel Graeber ◽  
Martin Kaupenjohann ◽  
Jan Siemens
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Liquid Nitrogen ◽  
Water Samples ◽  
Terrestrial Ecosystems ◽  
Spectroscopic Properties ◽  
Fluorescence Excitation ◽  
Total Fluorescence ◽  
Litter Leachate ◽  
Fast Freezing

Abstract. Freezing can affect concentrations and spectroscopic properties of dissolved organic matter (DOM) in water samples. Nevertheless, water samples are regularly frozen for sample preservation. In this study we tested the effect of different freezing methods (standard freezing at −18 °C and fast-freezing with liquid nitrogen) on DOM concentrations measured as organic carbon (DOC) concentrations and on spectroscopic properties of DOM from different terrestrial ecosystems (forest and grassland). Fresh and differently frozen throughfall, stemflow, litter leachate and soil solution samples were analyzed for DOC concentrations, UV-vis absorption and fluorescence excitation–emission matrices combined with parallel factor analysis (PARAFAC). Fast-freezing with liquid nitrogen prevented a significant decrease of DOC concentrations observed after freezing at −18 °C. Nonetheless, the share of PARAFAC components 1 (EXmax < 250 nm (340 nm), EXmax: 480 nm) and 2 (EXmax: 335 nm, EXmax: 408 nm) to total fluorescence and the humification index (HIX) decreased after both freezing treatments, while the shares of component 3 (EXmax: < 250 nm (305 nm), EXmax: 438 nm) as well as SUVA254 increased. The contribution of PARAFAC component 4 (EXmax: 280 nm, EXmax: 328 nm) to total fluorescence was not affected by freezing. We recommend fast-freezing with liquid nitrogen for preservation of bulk DOC concentrations of samples from terrestrial sources, whereas immediate measuring is preferable to preserve spectroscopic properties of DOM.

scholarly journals Fluorescence analysis allows to predict the oxidative capacity of humic quinones in dissolved organic matter: implication for pollutant degradation

2020 ◽  
Author(s):  
Davide Palma ◽  
Edith Parlanti ◽  
Mahaut Sourzac ◽  
Olivier Voldoire ◽  
Aude Beauger ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Water Samples ◽  
Three Dimensional ◽  
Complex Mixture ◽  
Fluorescence Analysis ◽  
Oxidative Capacity ◽  
Reactive Species ◽  
Solar Light ◽  
Pollutant Degradation

AbstractDissolved organic matter (DOM) controls the degradation and sequestration of aquatic pollutants and, in turn, water quality. In particular, pollutant degradation is performed by oxidant species that are generated by exposure of DOM to solar light, yet, since DOM is a very complex mixture of poorly known substances, the relationships between potential oxidant precursors in DOM and their oxydative capacity is poorly known. Here, we hypothesized that production of oxidant species could be predicted using fluorescence analysis. We analysed water samples from an alluvial plain by fluorescence spectroscopy; the three-dimensional spectra were then decomposed into seven individual components using a multi-way algorithm. Components include a protein-like fluorophore, e.g. tryptophan-like and tyrosine-like, three humic fluorophores, 2-naphthoxyacetic acid, and a by-product. We compared component levels with the ability of water samples to generate reactive species under solar light. The results show a strong correlation between reactive species production and the intensity of two humic-like fluorophores assigned to reduced quinones. Monitoring these fluorophores should thus allow to predict the ability of DOM degradation of pollutants in surface waters.

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