The ocean or the marine microorganisms are the microbes of the sea and ocean environment. They are important because they regulate the biogeochemical cycles.
Marine microbes are crucial and play a major role in the regulation and control of the biogeochemical cycles of the marine ecosystem. They include bacteria, fungi, archaea etc.
They regulate and influences the marine environment and are a part of the marine ecosystem and cycles. They take part in the cycles of nitrogen and carbon that includes the breaking and utilizing of certain dead materials and compounds.
Therefore, marine microbes are crucial as option A. they control the biogeochemical cycles.
Learn more about marine microbes here:
https://brainly.com/question/1257032