Microbial carbon monoxide uptake in the St. Lawrence estuarine system

Marine Ecology Progress Series

Patrick Poulin¹  Huixiang Xie¹  Karine Lemarchand¹  Yong Zhang¹ 

关键词: Carbon monoxide;    Microbial uptake;    Seasonal variation;    Temperature dependence;    Bacteria;    Suspended particles;    Estuarine waters;    Gulf of St. Lawrence;   

DOI  :  10.3354/meps08175

学科分类：海洋学与技术

来源: Inter-Research

【 摘 要 】

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, 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.

【 授权许可】

Unknown