# scale_MO2: Mass-correct metabolic rate In respirometry: Tools for Conducting and Analyzing Respirometry Experiments

## Description

For most organisms, metabolic rate does not scale linearly, but rather according to a power function. This function estimates MO2 or size of an individual organism given the MO2 and size of another individual of a different size. To mass-correct your MO2 data, plug in your desired mass in `mass_2` and the output from `calc_b` to the `b` parameter.

## Usage

 `1` ```scale_MO2(mass_1, MO2_1, mass_2, MO2_2, b = 0.75) ```

## Arguments

 `mass_1` animal mass for `MO2_1`. `MO2_1` metabolic rate for `mass_1`. `mass_2` animal mass for `MO2_2`. `MO2_2` metabolic rate for `mass_2`. `b` scaling coefficient for MO2. Default is 0.75.

## Details

(MO2 = b0 * M^b)

where `b0` is species-specific normalization constant, `M` is mass and `b` is the scaling coefficient which is around 0.75 for many organisms.

For scaling of mass-specific metabolic rates, use something closer to `b = -0.25` rather than `b = 0.75`.

## Author(s)

Matthew A. Birk, matthewabirk@gmail.com

`Q10`, `calc_b`
 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36``` ```# I know a species has an SMR of 800 umol O2/h at 200 g. # What would be a likely SMR for a 300 g individual? scale_MO2(mass_1 = 200, MO2_1 = 800, mass_2 = 300) # Some squids have a much higher scaling coefficient: scale_MO2(mass_1 = 200, MO2_1 = 800, mass_2 = 300, b = 0.92) # A 100 g individual at 10 *C has an MO2 of 1270 umol/h. How much # would a 250 g individual likely consume at 14 *C? Q10(Q10 = 2, R1 = scale_MO2(mass_1 = 100, MO2_1 = 1270, mass_2 = 250), T1 = 10, T2 = 14) # Now I have data from real animals and I want to mass-correct them all to a 10 g animal. mass = 2:20 # obviously not real but you get the point mo2 = c(44.8, 41, 36, 35, 35, 33.5, 34.5, 40, 30, 23, 27, 30, 25.6, 27.8, 28, 24, 27, 28, 20) desired_mass = 10 b = calc_b(mass = mass, MO2 = mo2) scale_MO2(mass_1 = mass, MO2_1 = mo2, mass_2 = desired_mass, b = b\$b) plot(mass, mo2, ylab = 'Raw MO2') # before plot(mass, scale_MO2(mass_1 = mass, MO2_1 = mo2, mass_2 = 10, b = b\$b), ylab = 'Mass-corrected MO2') # after # Visualize MO2 scaling by mass and temperature: mass <- seq(10, 200, 10) temp <- 10:25 base_mass <- 50 base_temp <- 20 base_MO2 <- 750 mo2 <- outer(mass, temp, function(mass, temp){ scale_MO2(mass_1 = base_mass, mass_2 = mass, MO2_1 = Q10(Q10 = 2, R1 = base_MO2, T1 = base_temp, T2 = temp)) }) persp(mass, temp, mo2, xlab = 'Mass (g)', ylab = 'Temperature (*C)', zlab = 'MO2 (umol / hr)', theta = 35, phi = 15, expand = 0.5, ticktype = 'detailed', nticks = 10) ```