Photo-reactivity of natural dissolved organic matter from fresh to marine waters in the Florida Everglades, USA

2014 ◽  
Vol 16 (4) ◽  
pp. 866-878 ◽  
Author(s):  
Stephen A. Timko ◽  
Cristina Romera-Castillo ◽  
Rudolf Jaffé ◽  
William J. Cooper
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Reactive Species ◽  
Florida Everglades ◽  
Marine Waters ◽  
Salinity Gradients ◽  
Photo Production

Photo-production of reactive species by NOM in the Florida Everglades was examined across salinity gradients and coupled with PARAFAC analysis.

Molecular characterization of dissolved organic matter in freshwater wetlands of the Florida Everglades

2003 ◽  
Vol 37 (11) ◽  
pp. 2599-2606 ◽  
Author(s):  
X.Q. Lu ◽  
N. Maie ◽  
J.V. Hanna ◽  
D.L. Childers ◽  
R. Jaffé
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Molecular Characterization ◽  
Freshwater Wetlands ◽  
Florida Everglades

scholarly journals A new model for the global biogeochemical cycle of carbonyl sulfide – Part 1: Assessment of direct marine emissions with an oceanic general circulation and biogeochemistry model

2015 ◽  
Vol 15 (5) ◽  
pp. 2295-2312 ◽  
Author(s):  
T. Launois ◽  
S. Belviso ◽  
L. Bopp ◽  
C. G. Fichot ◽  
P. Peylin
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
General Circulation ◽  
Carbonyl Sulfide ◽  
Chromophoric Dissolved Organic Matter ◽  
Quantum Yields ◽  
Global Budget ◽  
Ecosystem Studies ◽  
Color Data ◽  
Photo Production

Abstract. The global budget of tropospheric carbonyl sulfide (OCS) is believed to be at equilibrium because background air concentrations have remained roughly stable over at least the last decade. Since the uptake of OCS by leaves (associated with photosynthesis) and soils have been revised significantly upwards recently, an equilibrated budget can only be obtained with a compensatory source of OCS. It has been assumed that the missing source of OCS comes from the low-latitude ocean, following the incident solar flux. The present work uses parameterizations of major production and removal processes of organic compounds in the NEMO-PISCES (Nucleus for European Modelling of the Ocean, Pelagic Interaction Scheme for Carbon and Ecosystem Studies) ocean general circulation and biogeochemistry model to assess the marine source of OCS. In addition, the OCS photo-production rates computed with the NEMO-PISCES model~were evaluated independently using the UV absorption coefficient of chromophoric dissolved organic matter (derived from satellite ocean color data) and apparent quantum yields available in the literature. Our simulations show global direct marine emissions of OCS in the range of 573–3997 GgS yr−1, depending mostly on the quantification of the absorption rate of chromophoric dissolved organic matter. The high estimates of that range are unlikely, as they correspond to a formulation that most likely overestimate photo-production process. Low and medium (813 GgS yr−1) estimates derived from the NEMO-PISCES model are however consistent spatially and temporally~with the suggested missing source of Berry et al. (2013), allowing us thus to close the global budget of OCS given the recent estimates of leaf and soil OCS uptake.

scholarly journals From Fresh to Marine Waters: Characterization and Fate of Dissolved Organic Matter in the Lena River Delta Region, Siberia

2015 ◽  
Vol 2 ◽  
Author(s):  
Rafael Gonçalves-Araujo ◽  
Colin A. Stedmon ◽  
Birgit Heim ◽  
Ivan Dubinenkov ◽  
Alexandra Kraberg ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
River Delta ◽  
Delta Region ◽  
Marine Waters ◽  
Lena River ◽  
Lena River Delta

Measuring dissolved organic matter in estuarine and marine waters: size-exclusion chromatography with various detection methods

2018 ◽  
Vol 15 (7) ◽  
pp. 436 ◽  
Author(s):  
Gabriel Dulaquais ◽  
Johann Breitenstein ◽  
Matthieu Waeles ◽  
Rémi Marsac ◽  
Ricardo Riso
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Organic Carbon ◽  
Dissolved Organic Matter ◽  
Humic Substances ◽  
Size Exclusion Chromatography ◽  
Size Exclusion ◽  
Marine Waters ◽  
Wide Range ◽  
Exclusion Chromatography

Environmental contextDissolved organic matter (DOM), a key parameter in aquatic biogeochemistry, is difficult to characterise owing to its variable composition and structure. We report a chromatographic method with carbon, nitrogen and absorbance detection able to record the size distribution of DOM and changes in its composition. The method could be used to identify additional sources to river or coastal waters as well as monitoring the DOM size/reactivity continuum in open oceans. AbstractWe studied the performance and limitations of size-exclusion chromatography with organic carbon, ultraviolet and organic nitrogen detectors (SEC-OCD-UVD-OND) for characterising dissolved organic matter (DOM) in estuarine and marine waters. We identified a strong salt effect on dissolved organic carbon (DOC) determination; however, calibration gave good results at salinity levels close to those of the sample analysed (ΔS ± 2 psu (practical salinity units)), with limited matrix effects, enabling an accurate measurement of DOC, as demonstrated by an intercalibration exercise. The repeatability, reproducibility and limit of detection (3 ppb for both carbon and nitrogen) for the three detectors demonstrated the robustness of the method for a wide range of natural waters, including carbon-rich freshwaters and deep seawaters with low carbon content (6000 ppb-C to 300 ppb-C). Deeper analysis of the SEC demonstrated that proteins and polysaccharides are partly fractionated within the column, and that terrestrial humic substances, isolated on a XAD-8 resin, can also be eluted in both fractions associated with biopolymers and low-molecular-weight neutrals. Application of the method to the study of DOM along a macrotidal estuary that was influenced by agricultural activities revealed significant changes in its composition despite a conservative DOC distribution. Distinct origins and qualities of high-molecular-weight (>500 kDa) organic compounds were identified for riverine and marine end-members. A new diagram to track changes in DOM lability is proposed to complete the humic-substances diagram.

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