 For example, a study on phytoplankton changes in the Indian Ocean indicates a decline of up to 20% in marine phytoplankton during the past six decades.During summer, the western Indian Ocean is home to one of the largest concentrations of marine phytoplankton blooms in the world.Increased warming in the Indian Ocean enhances ocean stratification, which prevents nutrient mixing in the euphotic zone where ample light is available for photosynthesis.