Carbon Dioxide Supersaturation in the Surface Waters of Lakes

Abstract

Data on the partial pressure of carbon dioxide (CO(2)) in the surface waters from a large number of lakes (1835) with a worldwide distribution show that only a small proportion of the 4665 samples analyzed (less than 10 percent) were within +/-20 percent of equilibrium with the atmosphere and that most samples (87 percent) were supersaturated. The mean partial pressure of CO(2) averaged 1036 microatmospheres, about three times the value in the overlying atmosphere, indicating that lakes are sources rather than sinks of atmospheric CO(2). On a global scale, the potential efflux of CO(2) from lakes (about 0.14 x 10(15) grams of carbon per year) is about half as large as riverine transport of organic plus inorganic carbon to the ocean. Lakes are a small but potentially important conduit for carbon from terrestrial sources to the atmospheric sink.

Carbon source/sink function of a subtropical, eutrophic lake determined from an overall mass balance and a gas exchange and carbon burial balance

“…A relatively low ratio of gas emission across the watereair interface (752 t) to carbon burial into sediments (9481 t) of 0.08 Cole et al (1994) further indicates that Lake Donghu is a significant carbon sink. Both the overall mass balance and the gas exchange and carbon burial balance showed Lake Donghu to be a carbon sink.…”

“…Compared to large lakes, small lakes are proportionally more important for carbon burial (Kortelainen et al, 2004). On the other hand, many studies on gaseous carbon exchange across the watereair interface have found that nearly 90% of lakes are supersaturated with CO 2 with a net diffusion of CO 2 from surface waters (Cole et al, 1994;Rantakari and Kortelainen, 2005). Some investigations have also revealed that many freshwater ecosystems are important sources of CH 4 , particularly eutrophic lakes (Casper et al, 2000;Xing et al, 2004;Xing et al, 2005).…”

“…Up until now, mass balance carbon budget studies have been heavily biased towards north temperate lakes (Charlton, 1977;Eadie and Robertson, 1976;Maier and Swain, 1978;Mcconnaughey et al, 1994;Quay et al, 1986) where gaseous carbon (CO 2 and CH 4 ) fluxes, in particular CH 4 , were usually not taken into account. However, CO 2 and CH 4 fluxes across the watereair interface are relatively high (Cole et al, 1994;Xing et al, 2005) and are important parts of whole-lake carbon budgets (Quay et al, 1986;Cole and Caraco, 1998).…”

Long‐term decline in carbon dioxide supersaturation in rivers across the contiguous United States

“…Free CO 2 in ground waters is principally derived from respiration in soil environments, but can also be influenced by weathering production of DIC and alkalinity, and the resulting changes in pH. The flux of ground water enriched with terrestrially-derived (largely soil-respired) CO 2 , supplemented by the decomposition of terrestrial organic matter within streams, dominate the aquatic carbon cycle in most rivers, and makes these systems CO 2 supersaturated and net sources of CO 2 to the atmosphere [Kling et al, 1991;Cole et al, 1994;Jones andMulholland, 1998a, 1998b].…”

Photo‐oxidative production of dissolved inorganic carbon in lakes of different humic content

“…Most lakes are supersaturated with CO2 in comparison to the atmosphere (Cole et al 1994). Excess CO2 can be: introduced into the lake externally from the watershed.…”