Effect of Temperature on Heterotrophic Glucose Uptake, Mineralization, and Turnover Rates in Lake Sediments

Abstract

The V max and turnover rates (TR) of [ U - 14 C]glucose uptake and mineralization of Lake Kinneret (Israel) sediment are temperature dependent. The following activation energies were determined: glucose uptake, ∼15,000 cal (62,760 J); TR of glucose uptake, ∼10,000 cal (41,840 J); glucose mineralization, 7,500 to 15,000 cal (31,380 to 62,760 J); and TR of glucose mineralization, ∼15,000 cal. Q 10 values varied as follows: glucose uptake, ∼2.3; TR of glucose uptake, ∼1.8; and glucose mineralization, ∼2.5. K + S n values increased slightly with temperature and might reflect an increased K with increased temperatures. Glucose respiration/uptake ratios were low (9.5 to 12%) and were apparently not greatly influenced by the presence or absence of oxygen or by different assay temperatures. Aerobic or anaerobic sediments assayed under either aerobic or anaerobic conditions did not exhibit greatly different V max , TR, or K + S n values.