Diatom colonization dynamics in a lotic system

A series of three overlapping sets of slides were exposed in riffle and pool habitats in a fourth order river in the Upper Peninsula of Michigan. Species diversity and evenness peaked quickly during colonization. Seasonal changes appeared to strongly influence diatom species succession. Seasonal changes in water velocity, temperature, or light may have the same effect as the more dramatic flood events which reset periphyton to earlier successional stages, resulting in increased major changes in species composition of the periphyton diatom community.