Redox reactions of organic matter decomposition in a soft water lake

Abstract

Abstract. During a three year study (1985)(1986)(1987) we used a mass balance approach to study the oxidation and reduction reactions related to decomposition of organic carbon in Mirror Lake, New Hampshire. The stoichiometry of the reactions allows us to calculate an electron transfer budget for the summer stratification period in the lake. as well as in benthic chambers and sealed jars.The average decomposition rate measured as dissolved inorganic carbon (DIC) production was 5.33 mm01 m-2 d-l. The proportions of decomposition accounted for by the various electron acceptors varied both during the summer, as well as from year to year. On average, oxygen accounted for 43% of DIC production, while the processes involving sulfate, nitrate, iron and methane formation together accounted for 20%. Despite conservative assumptions we could not account for 37% of the DIC production. The general pattern, including excess DIC production, was also observed in chamber studies conducted over shallow-water sediments and in sealed-jar experiments.Data on burial rates of reduced iron minerals indicate that such minerals are not sufficient to account for the discrepancy in the electron budget. Our analysis suggests that another electron acceptor such as organic carbon reduction, either via fermentation or selective oxidation, is the most likely explanation of excess DIC production.

Diel Variation of Methane Fluxes in Summer in a Eutrophic Subtropical Lake in China

“…The more likely reason was the presence of a strong wind disturbance. Similarly, in Mirror Lake, CH4 release was apparently associated with heavy rain and passage of a hurricane (Mattson and Likens 1993). In a small productive lake, two release maxima occurred when wind speed and air pressure were both low (Casper et al 2000), and many other studies suggested that the gas exchange rate increases predictably with increasing wind speed (Wanninkhof 1992, Marino and Howarth 1993, Cole and Caraco 1998.…”

Effects of alternative electron acceptors on the activity and community structure of methane-producing and consuming microbes in the sediments of two shallow boreal lakes

“…During thermal stratification periods, the oxygenation of the sediment is inhibited, which leads to the exhaustion of sediment EAs (other than CO 2 ) by microbial processes (Bedard and Knowles 1991;Mattson and Likens 1993). In contrast, sediment oxygenation, which is induced by watercolumn mixing during spring and autumn, as well as by biological and physical turbation, activates the biogeochemical processes that regenerate the sediment EA pool.…”

The potential of methanotrophic bacteria to compensate for food quantity or food quality limitations in Daphnia

“…In lakes (also ponds, wetlands and streams), large quantities of organic matter are degraded under anaerobic conditions through methanogenesis (Rudd & Taylor 1980, Ingvorsen & Brock 1982, Mattson & Likens 1993. Lakes in particular have been found to be 'hot spots' of methane production and thus contribute a large amount (1−16%) to global natural methane emissions (Bastviken et al 2004).…”