Explain the ecological impact of a decline in phytoplankton by providing examples from the organization through the ecosystem levels of organism

Phytoplankton are small photosynthetic organisms that live water bodies. Decline in the levels of phytoplankton in any ecosystem can be detrimental. These organisms build the oxygen content of the water and is food to other organisms. Phytoplankton are fed on by zooplankton which are then fed on by fish larvae which are fed on by numerous predators.