The rate of photosynthesis (PPP, in μmol m−2 s−1\mu\text{mol m}^{-2}\text{ s}^{-1}μmol m−2 s−1) of an aquatic plant is measured at different water temperatures (TTT, in ∘C^\circ\text{C}∘C) and carbon dioxide concentrations (in ppm\text{ppm}ppm).
The graph below shows the typical photosynthetic rates under these different conditions.
Determine the percentage decrease from the photosynthetic rate at a temperature of 19∘C19^\circ\text{C}19∘C under a CO2\text{CO}_2CO2 concentration of 800 ppm800\text{ ppm}800 ppm to the photosynthetic rate at a temperature of 33∘C33^\circ\text{C}33∘C under a CO2\text{CO}_2CO2 concentration of 600 ppm600\text{ ppm}600 ppm.
Give your answer to one decimal place.
