Changes in Bacterial Numbers and Leucine Assimilation during Estimations of Microbial Respiratory Rates in Seawater by the Precision Winkler Method.

During incubation of seawater in bottles, the decrease in dissolved oxygen is often nonlinear over time scales frequently used to measure respiration. Numbers of bacteria always increase, and rates of assimilation of dissolved leucine often increase exponentially. This suggests that sample handling disrupts the previously existing food web, leading to shifts of trophic state and unbalanced growth. Potential errors in measuring respiratory rate can be minimized by documenting these variables.