What do you think would result if aquatic species of nitrogen fixing cyanobacteria suffered dramatic population decreases?

A)Algae populations would decline,but run off from industrial fixation would continue to provide enough nutrients to prevent their collapse.
B)Both the aquatic and terrestrial populations of autotrophs would collapse,with the end result that all life would cease to exist.
C)Algae populations would increase because they would have less competition for sunlight after the nitrogen fixing cyanobacteria were eliminated.
D)There would be no change in aquatic autotroph populations because nitrogen fixation by cyanobacteria is negligible.