Explain why it is important to study ocean microbes with regard to the biosphere.

It is crucial to study ocean microbes because THEY CONTROL THE MAJOR BIOGEOCHEMICAL CYCLES THAT KEEP EARTH'S BIOSPHERE IN BALANCE.

The ocean is made up of many microbes, which play important role in the process of biogeochemical cycling of various elements. For instance, microbes play a very important role in the biogeochemical cycling of carbon and nitrogen. In the nitrogen cycle, the microbes are responsible for breaking down the protein molecules that are found in the body of dead plants and animals. The proteins are broken down into constituent amino acids, which are then released back into soils. The soil used this ammonia as a source of nitrogen for growing plants.

Explanation:

they float because they are less dense than the water itself

something denser than water, like a rock, will sink to the bottom