Coupling effects of abiotic and biotic factors on molecular composition of dissolved organic matter in a freshwater wetland

Size-Based Characterization of Freshwater Dissolved Organic Matter finds Similarities within a Water Body Type across Different Canadian Ecozones

“…Agricultural groundwater sites contained the lowest BP proportions (Figure 3a). High BP proportions were found in Boreal and Arctic lakes, while moderate BP proportions were found in rivers and were similar to other studies using LC-OCD (He et al 2016; Catalán et al 2017) (Figure 3a). Similar BP fraction averages are found across a water-body type compared to different water-body types within an ecozone, and high BP proportions are indicative of lake or stream DOM.…”

“…Boxplots for each ecozone in a water-body type indicate the mean value and extend to the first and third quartile, while whiskers represent 1.5x inter-quartile range. Included are literature values that use LC-OCD in South Korea (He et al 2016) and Spain (Catalán et al 2017), and are denoted by symbols in grey. Literature values from South Korea include a maximum and minimum value found within the study (open circle).…”

“…Photolysis and in-situ production are two processes that occur among surface waters that alter the composition of DOM. Exposure of DOM to sunlight and photochemical transformations of humics results in smaller molecules and increased proportions of BB (Tercero Espinoza et al 2009; He et al 2016). This is observed in the dataset by a shift from PCA groupings with high BP (indicative of lakes, ponds, and streams) towards higher BB and LMWN suggestive of exposure to sunlight (Figure 4).…”

“…Size exclusion chromatography (SEC) has been used to characterize freshwater DOM in lakes (Kent et al 2014), rivers or streams (He et al 2016), and groundwaters (Szabo and Tuhkanen 2010). Liquid Chromatography – Organic Carbon Detection (LC-OCD) is a simple, fast (<120 minutes per sample), and quantitative SEC method that separates DOM based upon hydrodynamic radii (Huber et al 2011), characterizing both absorbing and non-absorbing DOM components.…”

“…Liquid Chromatography – Organic Carbon Detection (LC-OCD) is a simple, fast (<120 minutes per sample), and quantitative SEC method that separates DOM based upon hydrodynamic radii (Huber et al 2011), characterizing both absorbing and non-absorbing DOM components. Studies using LC-OCD have focussed on wastewater and water treatment applications (Ciputra et al 2010), with some data from agricultural and forested catchments in Germany (Heinz et al 2015), and rivers in South Korea (He et al 2016) and Spain (Catalán et al 2017). LC-OCD-based DOM groupings provide a relatively easy measure of DOM size-based composition across a large suite of environments.…”