Use the figure below to review the reactants and products of photosynthesis and respiration. with respect to carbon dioxide and oxygen concentrations, what trends would you expect to see in the epipelagic vs. the mesopelagic zones? why? the diagram shows the processes of photosynthesis and respiration. water, sunlight and carbon dioxide are shown entering the chloroplast and oxygen along with glucose passing into the mitochondrion where glucose then turns to energy and heat. a. i would expect to find equal concentrations of oxygen and carbon dioxide in the epipelagic and the mesopelagic zones because these zones are always well mixed. b. i would expect to find higher oxygen and lower carbon dioxide concentrations in the epipelagic zone because this is the well-lit zone in which photosynthesis occurs. c. i would expect to find lower oxygen and higher carbon dioxide concentrations in the epipelagic zone because this is the zone in which the majority of photosynthesis and respiration occurs. d. i would expect to find lower oxygen and lower carbon dioxide concentrations in the epipelagic zone because because this is where the majority of cellular respiration takes place.