COMPARISON OF BENTHIC OXYGEN DEMAND MEASUREMENT TECHNIQUES
Belanger, Thomas V.
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Several common methods to measure benthic oxygen demand were compared using measured and literature data. An in situ respirometer technique, a laboratory core-uptake technique and a laboratory flow-through system technique were compared on sand and organic sediment in Lake Washington, Florida. In situ uptake rates were significantly higher than core uptake rates, and this difference was greater for highly organic sediment than sand sediment. Measured and literature uptake values for in situ respirometer and core-uptake techniques with organic sediment were compared and resulted in a relationship (r = .99; P< .01) of the form: in situ uptake (g 2/m 2-hr) = .036 + 1.16 core uptake (g 2/m 2-hr). In many cases both coreuptake and in situ respirometer techniques under estimate oxygen consumption, due to difficulties in obtaining correct water velocities over the sediment surface. In the flow-through system studies, sediment oxygen uptake varied considerably with flow rate and a significant logarithmic relationship (P<.01) was obtained with Lake Apopka, Florida organic sediment. Measurement techniques that simulate field flows are the most accurate, such as the flow through system or the in situ tunnel respirometer technique.