The term 'bits of plankton' can be summarized as small pieces of ALGAE. ALGAE are a type of aquatic plant that are found in both freshwater and saltwater environments. They are an important part of the food chain, providing food for many species of fish, crustaceans, and other aquatic animals. ALGAE also play an important role in the global carbon cycle, helping to regulate the amount of carbon dioxide in the atmosphere.