Oxygen supply capacity breathes new life into the critical oxygen partial pressure (Pcrit) [RESEARCH ARTICLE]

We describe the α-method, in which the MR is monitored as oxygen declines and, for each measurement period, is divided by the corresponding PO2 to provide the concurrent oxygen supply (α0=MR/PO2). The highest α0 value (or, more conservatively, the mean of the three highest values) is designated as α. The same value of α is reached at Pcrit for any MR regardless of previous or subsequent metabolic activity. The metabolic rate needn't be constant (regulated), standardized, nor exhibit a clear-breakpoint at Pcrit for accurate determination of α. The α-method has several advantages over Pcrit determination and non-linear analyses, including: 1) less ambiguity and greater accuracy, 2) fewer constraints in respirometry methodology and analysis, and 3) greater predictive power and ecological and physiological insight. Across the species evaluated here, α values are correlated with MR, but not Pcrit. Rather than an index of hypoxia tolerance, Pcrit is a reflection of α, which evolves to support maximum energy demands and aerobic scope at the prevailing temperature and oxygen level.

Source: Journal of Experimental Biology - March 10, 2021 Category: Biology Authors: Seibel, B. A., Andres, A., Birk, M. A., Burns, A. L., Shaw, C. T., Timpe, A. W., Welsh, C. J. Tags: RESEARCH ARTICLE Source Type: research