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An investigation ofhydrogen peroxide chemistry in surface waters of Vineyard Sound with H218O2 and 18O2
Author(s) -
Moffett James W.,
Zajiriou Oliver C.
Publication year - 1990
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.1990.35.6.1221
Subject(s) - chemistry , peroxide , decomposition , seawater , environmental chemistry , organic chemistry , oceanography , geology
18 O‐labeled H 2 O 2 and O 2 have been used to determine absolute rates and pathways of peroxide formation and decay processes in surface waters of a coastal marine site. Reactions were followed by incubating seawater samples with 1 8 O 2 or H 2 18 O 2 and following the chemical transformation of the isotope label. Decomposition of H 2 18 O 2 was dominated by biological processes and led to the formation of 18 O 2 and H 2 18 O; the product distribution indicates that 65–80% of the decay was due to catalase with 20–35% due to peroxidase activity. Photochemical oxidation of H 2 18 O 2 to 18 O 2 was also observed. Particle‐dependent, light‐independent peroxide production was also observed in freshly collected samples, with rates ranging from 0.8 to 2.4 nM h −1 . These rates are low relative to photochemical production rates in surface waters, but may be important under conditions of low light intensity. Experiments with a metabolic inhibitor suggest that at least some of this production was biologically mediated. However, there was no evidence for light‐dependent biological production.