Synechococcus, a Cyanobacterium, Is a Free-Living Marine Organism That Fixes

Multiple Choice

Synechococcus, a cyanobacterium, is a free-living marine organism that fixes CO₂ into biomass while producing molecular oxygen utilized by swarms of heterotrophic bacteria. Its biomass provides food for protists and predators. What is the niche of this organism?

A) phototroph in the open ocean
B) base of the food chain
C) nitrogen assimilation for the ocean environment
D) all of the above
E) none of the above