Examination of endopelic and epilithic algal community structure employing scanning electron microscopy

1. Biological community structure within a stream periphyton mat and sediment core was examined using scanning electron microscopy. Samples were fixed, freeze‐fractured and viewed under normal conditions with a scanning electron microscope. 2. This technique enabled the analysis of orientation and spatial distribution of algal cells within the three‐dimensional algal communities. 3. Fractured samples from a periphyton mat and sediment core at the Procter & Gamble Experimental Stream Facility showed layering of some dominant diatom species, such as Nitzschia dissipata, Melosira varians and Gyrosigma attenuatum. The spatial relationship of nematodes as potential algal predators was also revealed. 4. Advantages, disadvantages and potential future applications of this freeze fracture technique are discussed.