Details

Autor(en) / Beteiligte

• Romera-Castillo, Cristina
• Chen, Meilian
• Yamashita, Youhei
• Jaffé, Rudolf

Titel

Fluorescence characteristics of size-fractionated dissolved organic matter: Implications for a molecular assembly based structure?

Ist Teil von

• Water research (Oxford), 2014-05, Vol.55, p.40-51

Ort / Verlag

Kidlington: Elsevier Ltd

Erscheinungsjahr

2014

Link zum Volltext

Quelle

Elsevier ScienceDirect Journals Complete

Beschreibungen/Notizen

• Surface freshwater samples from Everglades National Park, Florida, were used to investigate the size distributions of natural dissolved organic matter (DOM) and associated fluorescence characteristics along the molecular weight continuum. Samples were fractionated using size exclusion chromatography (SEC) and characterized by spectroscopic means, in particular Excitation-Emission Matrix fluorescence modeled with parallel factor analysis (EEM-PARAFAC). Most of the eight components obtained from PARAFAC modeling were broadly distributed across the DOM molecular weight range, and the optical properties of the eight size fractions for all samples studied were quite consistent among each other. Humic-like components presented a similar distribution in all the samples, with enrichment in the middle molecular weight range. Some variability in the relative distribution of the different humic-like components was observed among the different size fractions and among samples. The protein like fluorescence, although also generally present in all fractions, was more variable but generally enriched in the highest and lowest molecular weight fractions. These observations are in agreement with the hypothesis of a supramolecular structure for DOM, and suggest that DOM fluorescence characteristics may be controlled by molecular assemblies with similar optical properties, distributed along the molecular weight continuum. This study highlights the importance of studying the molecular structure of DOM on a molecular size distribution perspective, which may have important implications in understanding the environmental dynamics such materials. [Display omitted] •Molecular size fraction distribution of the fluorescent pool of DOM was characterized.•Fluorescent DOM was broadly distributed along the size continuum.•Humic-like components were enriched in the middle size fractions.•Protein-like components were more abundant in the extreme size fractions.•FDOM seems to be composed of small units held together by weak dispersive forces.