Dinoflagellates are second major source of marine primary producers. They are important part of the food web in the oceans. They release large amount of energy into planktonic food webs. They are the major source of energy for other marine life. Diatoms are unicellular eukaryotic microalgae that play important role ecologically. They fix about 20% of total carbon. Similar to dinoflagellates, they are also major source of marine primary producters. Both these organisms contributes to climate change processes. They form a basis of the marine food web.