Examining the 1 H NMR spectrum, 6 distinct regions can be identified (Figure ), with ranges for these regions defined by previous work . Region A spans from 0.6 to 1.3 ppm, and consists of aliphatic polymethylene and methyl functionalities, while region B, spanning 1.3 -2.9 ppm, includes N-and O-substituted aliphatic signals. Further downfield, region C includes predominantly O-alkyl signals, and covers 2.9 -4.1 ppm. Region D is composed predominantly of the α-proton of peptides, comprising signals from 4.1 -4.8 ppm. The presence of the residual water peak at 4.79 ppm obscures any accurate integration of the anomeric protons of carbohydrates. Aromatic and phenolic hydrogen atoms can be observed between 6.2 and 7.8 ppm in region E. Finally, amidic protons can typically be observed in region F, from 7.8 -8.4 ppm. However, exchange with deuterium from the solvent means this signal is non-quantitative. The peak observed at 3.34 ppm is attributable to residual methanol. Finally, no peak at 6.57 ppm, typically attributed to lignin, is observed. The relative amounts of each accurately definable area (regions A -E) are presented in Table . The 1 H NMR spectra of TRM-0522 retains the key features that have previously been described for marine and freshwater DOM . Specifically, regions have been attributed to carbohydrates, CRAM, and aliphatic compounds . The aliphatic region has been described as including both peptide derived aliphatics, but also material derived from linear terpenoids (MDLT) . Roughly, the ranges displayed on Figure and Table correlate to these constituent molecules, with range A including aliphatics, range B including CRAM, and range C including carbohydrates. While the percentage contributions obtained by region integration can only approximately estimate the actual compound composition, the integrated ranges are in alignment with previously reported data that show CRAM as the most abundant component, followed by carbohydrates, and finally aliphatics . Of note is a pronounced feature at 3.52 -3.76 ppm, which in the majority of previously reported samples is not observed as a distinct peak . However, this peak is seen in spectra of samples isolated at several depths in the Atlantic ocean , and is possibly derived from methoxy-ether functionalities . Consistent with other marine water samples, TRM-0522 lacks strong signals attributable to alkenes or aromatics, indicating a low contribution from lignin, humic, and fulvic substances. This also corresponds well to our finding of very low SUVA254 (1.36 L -1 g cm -1 ).