With reference to the planet Earth, consider the following statements:Rain forests produce more oxyg

Question

With reference to the planet Earth, consider the following statements:Rain forests produce more oxygen than that produced by oceans.Marine phytoplankton and photo-synthetic bacteria produce about 50% of world's oxygen.Well-oxygenated surface water contains several folds higher oxygen than that in atmospheric airWhich of the statements given above is/are correct?

Accepted Answer

Scientists estimate that roughly half of the oxygen production on Earth comes from the ocean. The majority of this production is from oceanic plankton — drifting plants, algae, and some bacteria that can photosynthesize. One particular species, Prochlorococcus, is the smallest photosynthetic organism on Earth. But this little bacteria produces up to 20% of the oxygen in our entire biosphere. That’s a higher percentage than all of the tropical rainforests on land combined. Hence, statement I is not correct. More than half of the oxygen we breathe comes from marine photosynthesizers, like phytoplankton and seaweed. Both use carbon dioxide, water and energy from the sun to make food for themselves, releasing oxygen in the process. Hence, statement II is correct. Oxygen content is highest at the surface. As depth increases, dissolved oxygen declines, reaching a minimum between a few hundred meters and 1000 m deep, the aptly-named oxygen minimum layer. It should be noted that even though dissolved oxygen is highest at the surface, there is still far less oxygen in the water than is found in the air. Well-oxygenated surface water may only contain around 8 mg O2/l, while the air contains 210 mg O2/l. Hence, statement III is not correct.