Predicting Dissolved Lignin Phenol Concentrations in the Coastal Ocean from Chromophoric Dissolved Organic Matter (CDOM) Absorption Coefficients

Abstract

Dissolved lignin is a well-established biomarker of terrigenous dissolved organic matter (DOM) in the ocean, and a chromophoric component of DOM. Although evidence suggests there is a strong linkage between lignin concentrations and chromophoric dissolved organic matter (CDOM) absorption coefficients in coastal waters, the characteristics of this linkage and the existence of a relationship that is applicable across coastal oceans remain unclear. Here, 421 paired measurements of dissolved lignin concentrations (sum of nine lignin phenols) and CDOM absorption coefficients [a g (λ)] were used to examine their relationship along the river-ocean continuum (0-37 salinity) and across contrasting coastal oceans (sub-tropical, temperate, high-latitude). Overall, lignin concentrations spanned four orders of magnitude and revealed a strong, non-linear relationship with a g (λ). The characteristics of the relationship (shape, wavelength dependency, lignin-composition dependency) and evidence from degradation indicators were all consistent with lignin being an important driver of CDOM variability in coastal oceans, and suggested physical mixing and long-term photodegradation were important in shaping the relationship. These observations were used to develop two simple empirical models for estimating lignin concentrations from a g (λ) with a ±20% error relative to measured values. The models are expected to be applicable in most coastal oceans influenced by terrigenous inputs.

The fate of terrigenous dissolved organic carbon on the Eurasian shelves and export to the North Atlantic

“…Trends in CDOM, lignin phenol concentrations, and distinct patterns for P/V and S/V ratios in LSHW, LHW, Siberian rivers, Atlantic inflow, and Pacific waters provided some insights about the formation and modification of LSHW and LHW along the Siberian shelves. Ratios of P/V and S/V are influenced by vegetation source and alterations of tDOC due to photochemical and biological degradation, but along the Siberian shelves they primarily reflected unique source signatures of Siberian rivers [Benner and Kaiser, 2011;Amon et al, 2012;Fichot et al, 2016]. Elevated concentrations of CDOM and lignin phenols in LSHW and LHW waters Bauch et al [2009Bauch et al [ , 2011aBauch et al [ , 2011b and Anderson et al [2013].…”

Sources, Transport, and Transformation of Dissolved Organic Matter in a Large River System: Illustrated by the Changjiang River, China

“…Combining the optical proxies and biomarkers to characterize DOM, especially the linkage between CDOM (absorption or fluorescence) and dissolved lignin, has drawn the attention of researchers; however, most studies have focused on estuaries and coastal regions (Fichot et al, ; Lu et al, ; Osburn & Stedmon, ; Walker et al, ). Except for studies conducted in arctic rivers, which showed high dissolved organic carbon (DOC) concentrations, few studies have linked the optical and chemical properties of DOM in large fluvial systems (Mann et al, ; Spencer, Aiken, et al, ; Stubbins et al, ).…”

Differential effects of solid‐phase extraction resins on the measurement of dissolved lignin‐phenols and organic matter composition in natural waters

“…A fluorescence technique involves excitation and emission matrices (EEMs), which have been used to characterize the quality and source of DOM in aquatic environments (Coble et al ; Coble ). Recently, optical properties of colored DOM have been utilized to estimate DOC concentrations (Spencer et al ; Fichot and Benner ) and lignin phenol concentrations (Fichot and Benner ; Fichot et al ). Furthermore, optical properties such as spectral slope coefficient of DOM have been used to discuss the distribution of carbon normalized dissolved lignin yields in natural system via remote sensing (Fichot et al ).…”