In early spring and the fall the ratio of living diatoms to dead diatoms is high, whereas, in summer and winter the amount of dead diatoms outpopulates the living.[1] Based on this known information diatoms can verify the time of year samples were taken. Different types of diatoms can also determine the properties of a samples ecosystem. For example, the higher ratio of periphytic (type of platonic diatom), the higher the vegetation concentration and shallower the water, but the higher the ratio of scaled chrysophytes a sample means the environment of that organism contains more open water.[2] Forensic scientists can create differentiated markers on environments in the area they are collecting data based on the diatoms population growth rate, which is affected by pollutants in their water sources because the simple tissues of diatoms make them sensitive environmental changes.[5][6] The reason diatoms are a common tool to match water environments is because of the variability of their populations are predictable and constant, the organisms can be identified by using the light microscope, and their silica cell walls allow for preservation.[5]