Biology 3700 Environmental Control of Respiration
The rate of respiration ( Rate ) at any temperature ( Temp ) can be calculated using equation 1 shown below, if the temperature sensitivity of respiration (Q
10
) and respiration capacity at 10 °C (R
10
) are known.
Rate

R
10

Q
10
(
Temp

10
10
)
Equation 1
The definition of Q
10
is:

Q
10


Rate 2
Equation 2
Rate 1 where Rate2 is the rate of a process at temperature 2 (Temp2, °C) and Rate1 is the rate of a process at temperature 1 (Temp1, °C).




Temp 2
10

Temp 1



The capacity for respiration at 10 °C (R
10
) is known to vary with changes in carbohydrate substrate availability and soil moisture content. Both substrate availability and soil moisture content will vary substantially on a seasonal basis in most ecosystems.

Exercise
1.
Using the daily changes in air temperature shown in the excel file associated with this class assignment, calculate the expected diurnal changes in plant respiration in units of
 mol m -2 s -1 .
Assume that R
10
remains constant at 3
 mol m -2 s -1 during this day.
2.
Using the seasonal changes in air temperature, substrate availability and soil moisture content shown in the excel file associated with this class assignment, calculate the expected seasonal changes in plant respiration in units of
 mol m
-2
s
-1
. Assume that MaxR
10
is 3
 mol m
-2
s
-1 and calculate seasonal changes in R
10
using equation 4 shown above.
3.
Using the definition of Q
10
provided in equation 2, calculate the value of Q
10
given the following information: respiration rate at 15.3 °C was 4.7  mol m
-2
s
-1 , and respiration rate at 23.6 °C was
7.3
 mol m
-2
s
-1
.