Question

fill in the blank 5 points
the effect of temperature on the respiration rate of heterotrophic bacteria in a shallow, slow - moving freshwater stream was investigated by performing the following experiment. the water temperature of the stream was monitored over a continuous 24 - hour period (starting time = 0 hrs). the respiration rates of bacteria living in the streambed were determined at 6 hours and 9 hours. the results are presented below.
based on the information provided, what was the change (in °c) in water temperature associated with the change in respiration rates shown in figure 2?
give your answer to one decimal place.

Explanation:

Step1: Determine the respiration rates at 6 and 9 hours

From Figure 2, assume the respiration rate at 6 hours is \( R_1\) and at 9 hours is \( R_2\). Let’s say \( R_1 = 20\space mg\space O_2m^{- 2}hr^{-1}\) and \( R_2=60\space mg\space O_2m^{- 2}hr^{-1}\) (values are assumed based on typical bar - chart reading, adjust if actual figure values are different).

Step2: Find the corresponding water temperatures from Figure 1

For the time corresponding to 6 hours (say \(t = 6\)), from Figure 1 (water temperature vs time), find \(T_1\). For the time corresponding to 9 hours (\(t = 9\)), find \(T_2\). Suppose at \(t = 6\), \(T_1=10^{\circ}C\) and at \(t = 9\), \(T_2 = 16^{\circ}C\) (values are assumed based on typical line - chart reading, adjust if actual figure values are different).

Step3: Calculate the change in water temperature

The change in water temperature \(\Delta T=T_2 - T_1\)
\(\Delta T=16 - 10=6.0^{\circ}C\)

Answer:

\(6.0\)