For a DOC concentration of 10.1 mg L -1 , absorbance at 254 nm was 0.137 cm -1 , giving a SUVA254 of 1.36 L mg C -1 m -1 . SUVA254 typically ranges from 1.0 to 6.0 L mg C -1 m -1 in surface waters , although values > 6.0 L mg C -1 m -1 have been reported for samples with a strong terrestrial signal and values < 1 L mg-C -1 m -1 have been reported for samples dominated by fresh DOM production (e.g. algal leachate samples ). Coastal ocean samples typically exhibit values of around 1.5 -3.5 L mg C -1 m -1 , whilst open ocean samples tend to be closer to 1.0 L mg C -1 m -1 23 . Thus, the SUVA254 value of TRM-0522 (1.36 L mg C -1 m -1 ) is within the expected range and indicates a considerably lower degree of aromaticity relative to other available reference materials e.g. Suwannee River Natural Organic Matter (SRNOM; 5.34 L mg C -1 m -1 24 ), SRFA (4.20 mg C -1 m -1 25 ), and PLFA (2.0 -3.2 L mg C -1 m -1 26 ).