MEPS 290:1-14 (2005)  -  doi:10.3354/meps290001

Biological consumption of carbon monoxide in Delaware Bay, NW Atlantic and Beaufort Sea

Huixiang Xie1,*, Oliver C. Zafiriou2, Thomas P. Umile3,4, David J. Kieber3

1Institut des Sciences de la Mer de Rimouski, Université du Québec à Rimouski, 310 Allée des Ursulines, Rimouski, Québec G5L 3A1, Canada
2Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, 266 Woods Hole Road, Woods Hole, Massachusetts 02543, USA
3Department of Chemistry, College of Environmental Science and Forestry, State University of New York, 1 Forestry Drive, Syracuse, New York 13210, USA
4Present address: Department of Chemistry, The University of Scranton, 223 Monroe Avenue, Scranton, Pennsylvania 18510, USA

ABSTRACT: Microbial consumption is the dominant sink of oceanic carbon monoxide (CO), one of the major carbon-containing photoproducts of chromophoric dissolved organic matter in marine waters. This study presents first-order microbial CO consumption rate constants (kCO) determined using whole-water dark incubations in summer and fall in diverse marine ecosystems covering the Delaware Bay, NW Atlantic, and Beaufort Sea. The microbial CO consumption rate constant, kCO (mean ± SD) was 1.11 ± 0.76 h–1 in the Delaware Bay, 0.33 ± 0.26 h–1 in the coastal Atlantic, 0.099 ± 0.054 h–1 in the open Atlantic, 0.040 ± 0.012 h–1 in the coastal Beaufort Sea and 0.020 ± 0.0060 h–1 in the offshore Beaufort Sea. The kCO in the Delaware Bay covaried with chlorophyll a concentration ([chl a]), rising with increasing salinity in the range 0 to 19 and diminishing with further increasing salinity. The kCO in the Beaufort Sea is significantly positively correlated with [chl a]. Both the Atlantic and cross-system data sets showed significant positive correlations between kCO and the product of [chl a] and water temperature, suggesting that [chl a] can be used as an indicator of CO-consuming bacterial activity in the areas and seasons sampled in this study. Microbial CO consumption was shown to follow Wright-Hobbie kinetics, with variable but low half-saturation concentrations: ~1 nM in the Beaufort Sea and Gulf Stream and 2 to 18 nM in the coastal NW Atlantic. These low half-saturation concentrations suggest that microbial CO consumption in seawater is at times partly saturated, and that some previous microbial CO consumption rates determined with the commonly used 14CO method could be underestimates due to the addition of 14CO as a tracer substrate. The present study provides valuable data for coastal and Arctic waters whose kCO values are poorly or not constrained, including extensive data on the dependence of kCO on the concentration of CO.

KEY WORDS: Carbon monoxide · Microbial consumption · Wright-Hobbie kinetics · Marine waters

Full text in pdf format