Photochemistry of excited-state species in natural waters: A role for particulate organic matter

Indirect Photochemistry in Sunlit Surface Waters: Photoinduced Production of Reactive Transient Species

“…While it has been found that larger CDOM fractions and even suspended particles can yield reactive triplet states, [167] the formation of such transients is most effective upon irradiation of the smaller CDOM fractions. [168,169] Possibly, as already assumed, the HMW moieties of CDOM undergo fast internal conversion to their ground states and this deactivation process inhibits both fluorescence emission and photoreactivity.…”

Marine Photochemistry of Organic Matter

“…Thus, the role of superoxide in directly oxidizing DOM oxidation and producing DIC is unknown, but likely minor. Highly energetic, excited state ketone triplets 3 (R 1 R 2 -CO)* are also known to oxidize DOM (Canonica et al, 2000;Cottrell et al, 2013;Golanoski et al, 2012), but like superoxide, their role in oxidizing DOM and producing DIC in natural waters is not known.…”

Interactions between protein-like and humic-like components in dissolved organic matter revealed by fluorescence quenching

“…In addition, we should note that the fluorescence quenching of other potential protein-like compounds, such as polyphenols produced by plant leaves (e.g., red mangrove) (Cuss and Gueguen, 2012;Maie et al, 2007), by humic-like compounds should be further revealed in future study. Additionally, it is of some interest to assess or distinguish the contributions of static and dynamic quenching using additional methods such as laser flash photolysis (Cottrell et al, 2013).…”