Phytoplanktons are found in littoral zone, which is shallow water region.Lakes subdivided into three zones by light penetration – photic vs. aphotic zones.The littoral zone is the near shore area where sunlight penetrates all the way to the sediment and allows aquatic plants (macrophytes) to grow. The limnetic (pelagic) zone is the open water area where light does not penetrate to the bottom.The benthic zone (bottom) covered by fine layers of mud in which animals live. The profoundal zone (deepest) relevant only in extremely deep lakes.