Triplicate 10 µl sub-samples were dried down in a Speedvac drying centrifuge and re-diluted in 11 mL MilliQ water for measurement of dissolved organic carbon (DOC; see below for method). DOC concentrations in these samples were 4.74 ± 0.44 mg L -1 (mean ± standard deviation), or 5297 ± 48.6 mg L -1 in the concentrated sample. This was equivalent to just 34 % of the total sample mass, with DOC typically representing > 40 % DOM in aquatic samples.