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

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.