Abstract:

Research method and ecology of freshwater picophytoplankton were reviewed.Glutaraldehyde or paraformaldehyde was usually used to fix picophytoplankton.The preserved sample should be put into refrigerator in order to prevent it from disintegration and loss of autofluorescence.Three different categories including picoeukaryotes,phycoerythrinrich picocyanobacteria and phycocyaninrich picocyanobacteria can be detected under epifluorescence microscope.Temperature,nutrient availability,grazing,light and pollution are the main factors that influence picophytoplankton.Basically,high temperature is favorable to picocyanobacteria and low temperature is favorable to picoeukaryotes.With the increasing of nutriens,picocyanobacteria numbers increased,but their contribution to the total phytoplankton biomass decreased.The researches of freshwater picophytoplankton were mainly done in temperate waters.Research in tropical and subtropical areas is rare,especielly in China.Such studies should be strengthened to understand more about freshwater picophytoplankton.