Carbon and Oxygen fluxes from small ponds: a significant carbon source to the atmosphere from small headwater systems
Abstract
Over 250 days of 0.5 hr profiles (six level) have been analysed to determine the gas exchange fluxes of CO2 and O2 from a small pond (approx. 100mx100m; 1.2m max depth). Mirror Lake (Storrs, CT) exhibits net fluxes of both O2 and CO2 to the atmosphere of the order 83±90 mmoles CO2 m-2 day-1and 15±70 mmoles O2 m-2 day-1 indicating the pond is both highly productive and heterotrophic. The temporal variability of C flux is -10 to +1000mmoles CO2 m-2 day-1. If this pond is considered typical, the net flux of CO2 to the atmosphere from small ponds is order 1-3 x 1014 gC yr-1 making a net contribution to the carbon cycle comparable to lakes (1.4 x 1014 gC yr-1; Cole et al 1994) and rivers (3 x1014 gC yr-1; Maybeck 1993) and confirms a significant role for shallow aquatic systems in the carbon cycle. Microbial processing of allochthonous carbon in the pond strongly favors C export relative to O2 consumption via microbial pathways that utilize NO3 or fermentation; allochthonous terrestrial organic material exacerbates the export of carbon. Given the growth in number and area devoted to man-made ponds/impoundments and the large number of natural ponds (277million) worldwide, these small, shallow hydrologic systems represent an additional concern for global change and the carbon cycle.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2006
- Bibcode:
- 2006AGUFM.B52B..02T
- Keywords:
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- 0428 Carbon cycling (4806);
- 0438 Diel;
- seasonal;
- and annual cycles (4227);
- 0458 Limnology (1845;
- 4239;
- 4942);
- 0497 Wetlands (1890);
- 1848 Monitoring networks