Metabolic rate estimates for a eutrophic lake from diel dissolved oxygen signals

摘要

Estimates of net primary production,community respiration (R'),and gross primary production (P_g) are developed diels to several months,based on 4 months of robotic diels profiles of dissolved xoygen (DO) and temperaure.Metabolic rate calculations are made through application of a DO mass balance framework that also accommodates inputs and losses of DO mediated by exchange across the air-water interface and across the lower boundary of the productive layers. It is demonstrated that the dynamics of the flux across the air-water interface are important to the metabvolic rate estimates,while vertical mixing-based losses to the underlyinglayers can be ignored. Study average estimates of R'(1.49 g O_2 m~(-3) d~(-1) and P_g (1.60 g O-2 m~(-3) d~(-1) obtained by this non-isolated community approach are consistent with levels reported in the literature for similar chlorophyll alpha concentrations,based on isolated community protocols to measure these metabolic rates. The non-isolated community approach is shown to have limited utility for quantifying day-to-day changes in these rates in this lake,apparently because of orizontal exhange with waters of different DO concentrations however,this approach may support reliable estimates of metabolic rates at intermediate time scales;e.g.,several days to a week. The DO mass balance frameworkis demonstrated to be valuable in resolving the relative roles of various physical and biological processes in regualting the DO poolof the productive layers.