What does 'R' stand for in Odum's energy model?
R represents respiratory energy loss in Odum’s energy budget. After ingested energy is assimilated, organisms oxidize part of it to generate ATP for maintenance, movement, ion regulation, thermoregulation, and biosynthesis. That oxidation dissipates usable energy as heat and usually releases CO₂ and water, although matter remains available to biogeochemical cycles. Production equals the assimilated portion retained in growth and reproduction after respiration, making R central to both production efficiency and trophic-transfer calculations. Substrate stoichiometry links carbon processing to nu
Ref: Fundamentals of Ecology, Odum & Barrett, 5th Ed., Ch. 3