Answer:
Productivity is defined as rate of increase in biomass in an ecosystem.
Step-by-step explanation:
Fertilizers adds nutrients to the water. These nutrients if builds up in the aquatic system, it causes growth of the microorganisms which uses dissolved oxygen present in the water. One of the largest negative impact of adding iron to the oceans is that increased productivity will leads to increased respiration rates which leads to depleted oxygen in oceans. So, increased productive will affect the whole aquatic life.