Didymosphenia geminata is a nuisance diatom species that can form large amounts of stalk material that covers the streambed (Larnard et al. 2006). These blooms impact the aesthetic value and biodiversity of mountain streams across many parts of North America particularly the Rocky Mountain states. In recent years there has been an increase in nuisance blooms, as well as spreading to new watersheds (Spaulding and Elwell 2007). D. geminata tends to prefer regulated flow conditions downstream of reservoirs (Kirkwood et al. 2009). Studies in Boulder Creek, CO (Cullis 2009; Miller et al. 2009) and elsewhere (Kilroy et al. 2005; Kirkwood et al. 2007) have shown that elevated shear stress and bed disturbance are important in controlling growth.
Cullis JDS (2011): Shear resistance of the nuisance diatom Didymosphenia geminate. Colorado Water 28(2): 5-8..