Water Resources Research Act Program

Details for Project ID 2009CO201B

Understanding the Hydrologic Factors Affecting the Growth of the nuisance diatom Didymosphenia Geminata in Rivers

Institute: Colorado
Year Established: 2009 Start Date: 2009-03-01 End Date: 2010-02-28
Total Federal Funds: $5,000 Total Non-Federal Funds: $2,715

Principal Investigators: Diane McKnight

Project Summary: Didymosphenia geminata, or 'rock-snot', 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, and in recent years there has been an increase in nuisance blooms, as well as spreading to new watersheds (Spaulding and Elwell 2007). While some studies have considered the habitat preferences of D. geminata (Kilroy et al. 2005), none have looked in detail at the impact of flood events and bed disturbance, which are likely to be the primary controls on growth (Kirkwood et al. 2007). The aim of this study is to investigate the hydrologic factors controlling the growth of periphyton in mountain streams and in particular the role of flood events and bed disturbance on controlling the growth of D. geminata. The specific objective is to compare the factors affecting growth in the unregulated and as yet unimpacted rivers of the Rocky Mountain National Park (RMNP) with those in the more regulated and impacted Boulder Creek to determine whether the natural disturbance regime of the unregulated streams in the RMNP is sufficient to reduce the threat of invasion by D. geminata and whether restoring some of the natural disturbance regime through managed flood releases in Boulder Creek could control the future growth of D. geminata.