METABOLIC ALLOMETRY... 'm' Use this
somewhat specialized utility to make estimates of an animal's resting metabolism,
based on its size and taxonomic affiliation. The metabolism calculator has many potential uses; for example, you might want to use it as a 'reality check' if you think your own metabolic data are unexpectedly high or low.
The initial popup menu contains some very generalized equations, and also allows you to switch
to submenus for specific taxa (arthropods,
fish, birds, mammals, etc.). For most taxa, several different equations
are available (from different literature sources, which are described in
the 'help' field to the right). You can also pick the desired output
units. The energy equivalence of metabolism (joules per ml of oxygen
consumed) can be set with the 'O2
heat equivalence' selection in the "Respirometry"
submenu (EDIT menu); the default value
is 20.1 joules/ml. The mass coefficient in the allometric equation
('a' value) is adjusted to reflect whatever output unit is in use.
Results can be stored for later use.
Metabolism for all taxa are calculated from power functions:
metabolism = a Mb
(where a is the mass coefficient, M is mass, and b is the mass exponent)
This example shows an estimate of the resting metabolic rate (RMR) of
a 37.3 g bird, in units of ml O2/min.
The equation was derived from a paper published by Andrew Mckechnie and
Blair Wolf (Click here for a list of the references from which allometric equations were obtained.).
Note that the mass coefficient ('a' value)
and mass exponent are shown and can be edited, and that mass can be in either grams or kilograms. Also, it is possible
to make corrections for the effect of body temperature by making the appropriate
adjustments to the value of Tb and
Q10 (in this example, the 'base' Tb,
from which the equation was derived, is equal to the current Tb
so no temperature correction occurs). After changing values in the
edit fields, click the 'Compute' button to display the new results.
The 'Store' button 'remembers' the computed metabolism for later use (for example in other calculators). The 'Save' button, if present, lets you save the current mass coefficient and mass exponent values for future use, accessed as 'Custom coefficent and exponent' option in the Taxon popup. The 'Save' button is accessible only if the units are set to ml O2/min. NOTE: you will have to click the 'Save Current Preferences' button in the Preferences window if you want to have your custom values available the next time you run the program.
MINIMUM FLOWRATE... This is similar to the Metabolic allometry calculator, but it also makes an estimate of the flow rate necessary to maintain an acceptable oxygen concentration within a metabolism chamber. This example shows a calculation for a small shark in brackish water (since the osmolarity of water affects its oxygen capacity). Note that the osmolarity popup appears only for fish metabolism. Also keep in mind that the calculation is based on a user-entered maximum change in gas concentration or percent saturation, not on the absolute concentration or partial pressure of oxygen.

You can also adjust the activity intensity for the animal, ranging from inactive (minimal metabolism; MMR) to average daily metabolism (3 X MMR) to very vigorous activity -- up to 100X MMR, which is reasonable for some large flying insects.
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