Hydrogen peroxide distribution, production, and decay in boreal lakes

Abstract

Abstract:The distribution, production, and decay of hydrogen peroxide (H 2 O 2 ) were studied in 10 boreal lakes of differing physical-chemical characteristics. Diurnal and vertical fluctuations in H 2 O 2 concentration were followed in the lakes by sampling at six depths three times per day. In addition, incubations of water filtered through 0.2-µm mesh were made under artificial irradiation to study the abiotic production and decay of H 2 O 2 . H 2 O 2 concentrations after 8 h of artificial irradiation were significantly correlated with neither absorption coefficients at 320 nm nor with dissolved organic carbon (DOC) concentrations. However, H 2 O 2 concentration increased rapidly with DOC concentration among lakes with DOC concentrations below 10 mg·L -1 . The H 2 O 2 concentration after exposure to ultraviolet radiation was positively related to the half-life of H 2 O 2 , which in turn was negatively correlated with iron and manganese concentrations (r 2 = 0.68 and 0.70, respectively). In situ H 2 O 2 concentrations at the surface of the water column ranged between 30 and 1041 nmol·L -1 and were largely determined by the decay rates of H 2 O 2 and the mixing depth of the water column.

Effect of Humic Substance Photodegradation on Bacterial Growth and Respiration in Lake Water

“…Hydrogen peroxide did not affect BCP rates for the longer incubations because H 2 O 2 was not detected in the 43-h incubation of lake water with added irradiated humic substances. This loss of H 2 O 2 during the bacterial incubations is consistent with the 1-to 8-h half-life of hydrogen peroxide observed in high-DOM environments (22,32,58). However, since observed differences in BCP in our study represent net differences, it is possible that some inhibition of BCP occurred even in the longer incubations due to the possible photoproduction of long-lived inhibitory substances, e.g., phenolic compounds (29,40,48,58) and other effects (54).…”

“…Furthermore, this negative effect was positively correlated to the production of hydrogen peroxide. The experimental approach used in this study indicated that the production of inhibitory substances during HS irradiation can strongly impact microbially mediated processes in lakes and should be considered in future studies, as those substances can be transported in the water column and affect bacteria negatively even in layers below the influence of direct solar radiation (32). Future studies should examine the nature, stability, and relative importance of photochemically produced shortand long-lived inhibitory substances, including H 2 O 2 and phenolic compounds.…”

Carbocentric limnology: looking back, looking forward

“…Its role on the fate of nutrients, particularly phosphorus, is similar in that it modulates the extent to which they can be used by the phytoplankton (Francko and Heath 1982). In addition to modulating the fate of other elements, DOC is itself a source of highly reactive species such as hydrogen peroxide (Scully et al 1995;Hakkinen et al 2004) and hydroxyl radicals (Vione et al 2006) through various light-induced interactions such as the Fenton reaction or nitrate hydrolysis. These powerful oxidants will in turn break the complex DOC molecules into simpler constituents, rendering them more available to microbial degradation (Bertilsson et al 1999;Bertilsson and Tranvik 2000).…”

Selective effects of H₂O₂ on cyanobacterial photosynthesis

“…Hydrogen peroxide is a commonly encountered component in the aquatic environment (Häkkinen et al 2004). In natural conditions it originates predominantly as a side-product of oxygenic photosynthesis when exposure to high irradiance coincides with a limitation in replenishment of the conventional electron sinks, i.e.…”