PADI Divemaster Certification Practice Exam

Phytoplankton play a crucial role in the oceanic ecosystem as they are responsible for producing nearly all of the Earth’s oxygen through the process of photosynthesis. These microscopic organisms use sunlight to convert carbon dioxide and water into glucose and oxygen, contributing significantly to the atmospheric oxygen levels that are essential for the survival of most life forms on the planet. It is estimated that phytoplankton are responsible for producing about 50% of the Earth's oxygen supply, highlighting their vital function in maintaining the balance of oxygen in our atmosphere.

In contrast, the other statements do not accurately reflect the primary role of phytoplankton. While ocean currents are influenced by various factors, they are not directly generated by phytoplankton. Additionally, while phytoplankton can play a role in the decomposition of organic material, this is not their primary function; organisms like bacteria are primarily responsible for that process. Lastly, while phytoplankton do consume carbon dioxide, they do so as part of the process of photosynthesis rather than exclusively; they utilize it to produce oxygen and organic compounds necessary for their growth and energy.