Discuss the concentration gradients of carbon dioxide and oxygen in the ocean water column. What will be an ideal response?

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Oxygen is abundant near the surface in the ocean’s brightly lit upper layer because of the
activity of marine photosynthesizers (plants and plantlike organisms). Since plants and
plantlike organisms require carbon dioxide for photosynthesis, surface CO2 concentrations
tend to be low. A decrease in oxygen below the sunlit upper layer usually results from the
respiration of bacteria and marine animals, as well as, oxygen consumption through the decay
of tiny dead organisms slowly sinking through the area. Because photosynthesis cannot take
place in the dark, CO2 given off by animals and bacteria tends to build up at depths below the
sunlit layer. Levels of CO2 also increase with depth because its solubility increases as
pressure increases and temperature decreases. Oxygen levels are slightly higher in deeper
water because fewer animals are present to take up the oxygen that reaches these depths.