Depth profiles of chlorophyll a/carbon ratio (Chla/C), chlorophyllide a/carbon ratio (Chlida/C), pheophorbide a/carbon ratio (Phbida/C), pheophytin a/carbon ratio (Pha/C), and pyropheophytin a/carbon ratio (PyroPha/C).

Fig. 4 visualises differences in the degradation between the organic compounds, chlorophylls, and carbon. The chlorophyll a/carbon ratio decreased with depth, indicating that organic carbon is more slowly degraded than chlorophyll a (Table 6 and Fig. 4), whereas the pheophytin a/carbon ratio and the pyropheophytin a/carbon ratio increased with the depth, indicating the formation of pheophytin and pyropheophytin with depth (Table 6 and Fig. 4). Best fits for the chlorophyllide a/carbon ratio and pheophorbide a/carbon ratio vs. depth were also linear regression models, but they were not significant (Fig. 4).