Editorial: Linking Optical and Chemical Properties of Dissolved Organic Matter in Natural Waters

Osburn, Christopher L.; Bianchi, Thomas S.

doi:10.3389/fmars.2016.00223

Cited by 18 publications

(10 citation statements)

References 11 publications

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“…As the absorption and fluorescence characteristics of DOM are tightly linked to its composition (Osburn & Bianchi 2016), it can be assumed that the observed changes reflect chemical transformation of the DOM pool. This transformation is a result of biogeochemical processing of DOM that is not unidirectional with a common endpoint, but is a more dynamic set of processes that depend on various factors, such as initial DOM quality (Ruiz-González et al 2015;Amaral et al 2016), metabolism of the bacterial community (Cammack et al 2004;Logue et al 2015;Kaartokallio et al 2016) and inorganic nutrient status (Zweifel et al 1993;Asmala et al 2014).…”

Section: Discussionmentioning

confidence: 99%

Nutrient availability as major driver of phytoplankton-derived dissolved organic matter transformation in coastal environment

et al. 2017

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Incubation experiments were performed to examine the processing of fresh autochthonous dissolved organic matter (DOM) produced by coastal plankton communities in spring and autumn. The major driver of observed DOM dynamics was the seasonally variable inorganic nutrient status and characteristics of the initial bulk DOM, whereas the characteristics of the phytoplankton community seemed to have a minor role. Net accumulation of dissolved organic carbon (DOC) during the 18-d experiments was 3.4 and 9.2 µmol l-1 d-1 in P-limited spring and N-limited autumn, respectively. Bacterial bioassays revealed that the phytoplankton-derived DOC had surprisingly low proportions of biologically labile DOC, 12.6 % (spring) and 17.5 % (autumn). The optical characteristics of the DOM changed throughout the experiments, demonstrating continuous heterotrophic processing of the DOM pool. However, these temporal changes in optical characteristics of the DOM pool were not the same between seasons, indicating seasonally variable environmental drivers. Nitrogen and phosphorus availability is likely the main driver of these seasonal differences, affecting both phytoplankton extracellular release of DOM and its heterotrophic degradation by bacteria. These findings underline the complexity of the DOM production and consumption by the natural planktonic community, and show the importance of the prevailing environmental conditions regulating the DOM pathways.

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Section: Discussionmentioning

confidence: 99%

Nutrient availability as major driver of phytoplankton-derived dissolved organic matter transformation in coastal environment

et al. 2017

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“…Although this technique does not unambiguously reveal the structure of DOM compounds, it offers new possibilities for the characterization of individual formulae or classes of molecules. The linkage between optical and chemical properties of DOM in natural waters is a subject of rising interest among aquatic biogeochemists 23 . Recent studies have combined FT-ICR-MS and optical measurements to better understand the composition of DOM in natural waters 24 , 25 but few of them have directly related optical and molecular signatures 26 – 31 .…”

Section: Introductionmentioning

confidence: 99%

Linking optical and molecular signatures of dissolved organic matter in the Mediterranean Sea

Martínez-Pérez

Osterholz

Catalá

et al. 2017

Sci Rep

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Dissolved organic matter (DOM) plays a key role in global biogeochemical cycles and experiences changes in molecular composition as it undergoes processing. In the semi-closed basins of the oligotrophic Mediterranean Sea, these gradual molecular modifications can be observed in close proximity. In order to extend the spatial resolution of information on DOM molecular composition available from ultrahigh resolution mass spectrometry in this area, we relate this data to optical (fluorescence and absorption spectroscopy) measurements. Covariance between molecular formulae signal intensities and carbon-specific fluorescence intensities was examined by means of Spearman’s rank correlations. Fifty two per cent of the assigned molecular formulae were associated with at least one optical parameter, accounting for 70% of the total mass spectrum signal intensity. Furthermore, we obtained significant multiple linear regressions between optical and intensity-weighted molecular indices. The resulting regression equations were used to estimate molecular parameters such as the double bond equivalent, degradation state and occurrence of unsaturated aliphatic compounds from optical measurements. The statistical linkages between DOM molecular and optical properties illustrate that the simple, rapid and cost-efficient optical spectroscopic measurements provide valuable proxy information on the molecular composition of open ocean marine DOM.

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“…Three fluorescent components (C) were modelled: C1 and C2 (a combination of peaks A + M and A + C, respectively) attributable to humic compounds; and C3 (peak T), which is a "non-humic" component (Coble 1996;Stedmon et al 2003). The comparison of these components against the worldwide database Openfluor confirmed the correspondence of C1 and C2 with humic-like compounds (Yamashita et al 2010;Cawley et al 2012;Catalá et al 2015) and associated C3 with protein-like, aliphatic compounds likely derived from recent microbial production (Maie et al 2007;Kellerman et al 2015;Osburn and Bianchi 2016) (for details see Online Resource 1). .…”

Section: Characterization Of U Pinnatifida Exudatesmentioning

confidence: 76%

Undaria pinnatifida exudates trigger shifts in seawater chemistry and microbial communities from Atlantic Patagonian coasts

et al. 2021

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The invasive kelp Undaria pinnatifida has spread from northeastern Asia to temperate coastal environments worldwide, with profound effects on colonized ecosystems. In this work, we analyzed the effect of exudates from U. pinnatifida on the chemical and microbial properties of seawater from a semienclosed gulf from Atlantic Patagonia. Exudates of U. pinnatifida, consisting mainly of carbohydrates, were released at a rate of 1.6 ± 0.8 mg C g -1 algae day -1 , affecting the quality and optical properties of seawater in experimental incubations. Parallel factor analysis based on excitation-emission matrices collected from exudates revealed the presence of two humic-like and one non-humic fluorescent components. Exudate release stimulated microbial growth and polysaccharide degrading activity in seawater. After a 7-day incubation of fresh seawater with the exudates, changes in microbial community structure were analyzed by large-scale 16S rRNA gene amplicon sequencing. Copiotrophic and fermentative genera such as Spirochaeta (Spirochaetes) and Propionigenium (Fusobacteria) increased in the incubations with algal exudates. Genomic potential prediction revealed that the selected bacterial community could have higher ribosome content -an indicator of the potential for reaching higher metabolic rates -and genes for the degradation of complex organic compounds such as polysaccharides and other carbohydrates present in the exudates. Nutrient addition triggered the emergence of other microbial populations with different ecophysiological niches: unclassified Flavobacteriales, unclassified bacteria related to the recently described Phylum Kiritimatiellaeota, as well as potential pathogens such as Vibrio (Gammaproteobacteria) and Arcobacter (Epsilonproteobacteria), suggesting potential synergistic effects between invasive macroalgae and human activities. Keywords macroalgae; bacterial communities; 16S rRNA gene amplicon sequencing; DOM concentration and quality, Southwestern Atlantic .

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Editorial: Linking Optical and Chemical Properties of Dissolved Organic Matter in Natural Waters

Cited by 18 publications

References 11 publications

Nutrient availability as major driver of phytoplankton-derived dissolved organic matter transformation in coastal environment

Nutrient availability as major driver of phytoplankton-derived dissolved organic matter transformation in coastal environment

Linking optical and molecular signatures of dissolved organic matter in the Mediterranean Sea

Undaria pinnatifida exudates trigger shifts in seawater chemistry and microbial communities from Atlantic Patagonian coasts

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