Tracking biodegradation signatures in dissolved organic matter using spectroscopy

Dissolved organic matter undergoes extensive reworking by the microbial community in estuarine and marine environments. Despite this, the UV-visible absorbance spectrum of dissolved organic matter (i.e. CDOM) remains relatively featureless. Several notable studies have shown the value of calculating spectral slopes over various wavelength bands that correlate with properties such as molecular size and degree of photochemical bleaching (Helms et al 2008, Loiselle et al 2009). Recently, the application of statistical methods to CDOM absorbance spectra has found to be useful in identifying potential biological signatures in DOM (Reader et al 2015, Asmala et al 2018).

Here we present a study of estuarine DOM from Bonne Bay, Western Newfoundland, Canada. The DOM samples were exposed to long-term biodegradation (5 sites, 14 weeks), and show how biodegradation can be tracked easily over time using different spectroscopic techniques.