Prior to irradiation, FDOM in the NELHA 674 m Pacific Ocean RO/ED isolate exhibited a
WP1130 peak at 253ex/426em (Peak A) (Fig. 6 and Fig.
cool and had a FI value of 1.53, a HIX value of 3.9, and a BIX value of 0.74 (Table 2 and Table 3). The M:C, FI, and BIX values of the NELHA 674 m RO/ED isolate (prior to irradiation) were similar to those found in a non-irradiated surface water RO/ED isolate from the same region (Station ALOHA; Table 3), while HIX was much higher than the surface water isolate (3.90 vs. 1.82 for 5 m ALOHA isolate; Table 3) and lower than the value measured for DOM isolated from 3500 m (HIX = 4.6). This trend with depth is also evident in the non-isolated (non-irradiated) seawater values for HIX (Table 3; Fig. 7), though all the values are lower than the DOM isolates. Prior to irradiation, Peak M was slightly more intense than Peak C for the 674 m RO/ED isolate (Table 2; Fig.
cool with an M:C value of 1.17 (Table 3). In comparison, the M:C value was 1.21 in the 5 m ALOHA RO/ED isolate and 1.13 in the 3500 m ALOHA isolate. Again,
exothermic trend with depth is similar to the M:C values measured for the non-isolated ALOHA samples (Fig. 7D).
