Microbial carbon monoxide uptake in the St. Lawrence estuarine system

作者：Xie Huixiang^*; Zhang Yong; Lemarchand Karine; Poulin Patrick

来源：Marine Ecology Progress Series, 2009, 389: 17-29.

DOI：10.3354/meps08175

• Carbon monoxide
• Microbial uptake
• Seasonal variation
• Temperature dependence
• Bacteria
• Suspended particles
• Estuarine waters
• Gulf of St. Lawrence

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, K-co, decreased from the upper estuary (8.48 d(-1)) to the lower estuary (3.94 d(-1)) and the gulf (1.32 d(-1)). K-co 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 K-co 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 K-co. Temperature dependence of K-co 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 K-co. CO uptake rate versus [CO] plots show typical Michaelis-Menten kinetics or inhibition behavior at elevated [CO]. K-m 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.

• 出版日期2009