Using synchronous fluorescence spectroscopy and principal components analysis to monitor dissolved organic matter dynamics in a glacier system

Abstract

Abstract:The molecular characteristics of dissolved organic matter (DOM) reflect both its source material and its biogeochemical history. In glacial systems, DOM characteristics might be expected to change over the course of a melt season as changes in the glacier drainage system cause the mobilization of DOM from different OM pools. To test this hypothesis we used Principal Components Analysis (PCA) of synchronous fluorescence spectra to detect and describe changes in the DOM in meltwater from a glacier system in the Coast Mountains of northern British Columbia, Canada. For most of the melt season, the dominant component of subglacially routed meltwater DOM is characterized by a tyrosine-like fluorophore. This DOM component is most likely derived from supraglacial snowmelt. During periods of high discharge, a second component of DOM is present which is humic in character and similar to DOM sampled from a nearby non-glacial stream. This DOM component is inferred to be derived from a moss-covered soil environment that has been glacially overrun. It is probably entrained into glacial melt waters when the supraglacial meltwater flux exceeds the capacity of the principal subglacial drainage channels and water floods areas of the glacier bed that are normally isolated from the subglacial drainage system. Another source of DOM also appears to be mobilized during periods of high air temperatures. It is characterized by both humic and proteinaceous fluorophores and may be derived from the drainage of supraglacial cryoconite holes.

Cross-connection detection in Australian dual reticulation systems by monitoring inherent fluorescent organic matter

“…These multivariate approaches have been applied to fluorescence-based water research to detect the presence and quantify the underlying fluorescence characteristics of complex mixtures of DOM [98,125]. A number of studies have been carried out on fluorescent DOM with multivariate analysis techniques in marine water [126], estuarine water [96,127,128], fresh water [86,129] glacial systems [130,131] and, more recently, in drinking water [114,132] and sewage treatment [133], including process performance [134] as well as to elucidate changes in fluorescence throughout the treatment trains of a number of water recycling plants [135]. Another approach to the interpretation of EEM data is by fluorescence regional integration (FRI) -a method where the EEM is divided into separate regions as appropriate and the intensity area of each region is integrated for comparison [136].…”

Source and biolability of ancient dissolved organic matter in glacier and lake ecosystems on the Tibetan Plateau

“…Previous studies have examined the sources and bulk DOM composition in both glacier and alpine lake ecosystems utilizing stable and radiocarbon isotope measurements (d 13 C-DOC, D 14 C-DOC), and optical techniques such as fluorescence spectroscopy (Barker et al, 2009;Hood et al, 2009;Mladenov et al, 2009). In recent studies, ultrahigh-resolution electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) has been used to examine DOM molecular composition in glacier ecosystems (Bhatia et al, 2010;Singer et al, 2012;.…”

Runoff- and erosion-driven transport of cattle slurry: linking molecular tracers to hydrological processes

“…Barker et al, 2009;Birdwell and Engel, 2010). However, the signal was more difficult to detect in this case because the soil-derived DOM swamped the slurry signal, making it difficult to resolve the two sources.…”