MEPS 389:17-29 (2009)  -  DOI: https://doi.org/10.3354/meps08175

Microbial carbon monoxide uptake in the St. Lawrence estuarine system

Huixiang Xie1,*, Yong Zhang1,2, Karine Lemarchand1, Patrick Poulin1

1Institut des Sciences de la Mer, Université du Québec à Rimouski, 310 allée des Ursulines, Rimouski, Québec G5L 3A1, Canada
2Present address: Yantai Institute of Coastal Zone Research for Sustainable Development, Chinese Academy of Sciences, 17 Chunhui Road, Laishan District, 264003 Yantai, PR China

ABSTRACT: Microbial uptake of carbon monoxide (CO) in the Gulf of St. Lawrence and the estuary of the St. Lawrence River, Canada, typically followed first-order kinetics at ambient CO concentrations, [CO], but saturation kinetics occasionally occurred in spring. The first-order uptake rate constant, Kco, decreased from the upper estuary (8.48 d–1) to the lower estuary (3.94 d–1) and the gulf (1.32 d–1). Kco inversely varied with tide and decreased from its highest value in summer (7.52 d–1) to intermediate values in spring (5.15 d–1) and autumn (4.12 d–1), and to its lowest value in winter (1.09 d–1). Maximum Kco values always occurred in a turbidity maximum zone near the head of the estuary. An empirical model was proposed to account for the effect of particle-associated bacteria on Kco. Temperature dependence of Kco obeyed Arrhenius behavior with the activation energy being lower in the upper estuary (21.5 kJ mol–1) than in the lower estuary and gulf (32.7 kJ mol–1). The combination of bacterial abundance and temperature can serve as an all-season predictive tool for Kco. CO uptake rate versus [CO] plots show typical Michaelis-Menten kinetics or inhibition behavior at elevated [CO]. Km was low and relatively invariable: 3.2 nmol l–1 [CO] in autumn and 4.9 nmol l–1 [CO] in winter. CO specific affinity in autumn (1.25 l (mg of cell)–1 h–1) more than doubled that observed in winter (0.51 l (mg of cell)–1 h–1). This study demonstrated strong seasonal variations in microbial CO uptake and complex influences of various biotic and abiotic variables on this process.


KEY WORDS: Carbon monoxide · Microbial uptake · Seasonal variation · Temperature dependence · Bacteria · Suspended particles · Estuarine waters · Gulf of St. Lawrence


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Cite this article as: Xie H, Zhang Y, Lemarchand K, Poulin P (2009) Microbial carbon monoxide uptake in the St. Lawrence estuarine system. Mar Ecol Prog Ser 389:17-29. https://doi.org/10.3354/meps08175

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