Walter visited Thailand during his vacation. He was surprised to see green water at a beach. What could be the reason for the phenomenon

When Walter visited Thailand during his vacation, he was surprised to see green water at a beach. because. It is because the ocean over this region has a high concentrations of phytoplankton from blue-green to green, depending upon the type and density of the population. The more phytoplankton in the water, the greener it is.