Bromothymol blue indicator is blue under neutral or alkaline conditions. It turns yellow when the concentration of dissolved carbon dioxide increases, lowering the pH of the solution.
An investigation was set up to compare the respiration of different specimens in an aquatic environment. The results after 1 hour are shown in Table 1.
| Specimen in test tube | Colour of bromothymol blue indicator |
|---|---|
| Living freshwater shrimp (Gammarus) | Yellow |
| Boiled freshwater shrimp (Gammarus) | Blue |
| Glass beads | Blue |
Explain why the result for the living freshwater shrimp is different from the result for the boiled freshwater shrimp.