In the recent years, particularly since the 2002 drought, the presence of Didymosphenia Geminata have significantly increased in Colorado mountain streams. Didymosphenia geminata is a nuisance algal species also known as "didymo" or "rock snot". Didymo can coat streambeds as a thick brown algal mat, with mats as thick as 1-2cm. Click here to get more details and microscopic views of D. geminata.
A study was conducted along Boulder Creek from 2008-2010 to investigate factors affecting the removal of D. geminta. Samples of D. geminata were collected at various points Boulder Creek(see map) between June 2008 and September 2010. Metrics for measuring didymo growth includes Didymo Rating Index (DRI), ash-free-dry-mass(AFDM), chlorophyll concentration and didymo cell densities. Didymo Rating Index(DRI) is a qualitative way to gauge didymo growth. It ranges from 0, representing no obvious signs of didymo growth, to a maximum of 10, representing 100% coverage and mats greater than 5 cm thick. The maximum DRI for Boulder Creek was a 6 or 7 (100% coverage with a mat thickness of 1 to 2cm).
Results of the study show the importance of taking into account site specific geomorphologic controls such as the potential for bed disturbance in addition to simple hydrologic controls such as variations in discharge. The results also show the importance of considering different controls for individual processes such distinguishing between the drivers of increased cell division or increased mat production in understanding the dynamics of complex ecological systems such as that presented by D. geminata.
Didymosphenia Geminata, diatom, Boulder Creek
XML is in ISO-19115 geographic metadata format, compatible with ESRI Geoportal Server.
Citation for This Dataset
Cullis, James. Removal of benthic algae in swift-flowing streams: the significance of spatial and temporal variation in shear stress and bed disturbance. Thesis submitted to the Faculty of the Graduate School of the University of Colorado in partial fulfillment of the requirement for the degree of Doctor of Philosophy Department of Civil, Environmental and Architectural Engineering
Citation for This Webpage
James Cullis (2010). "CZO Dataset: Boulder Creek - Diatoms (2008-2010) - Didymosphenia Geminata." Retrieved 25 Jun 2019, from http://criticalzone.org/national/data/dataset/2862/
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Map Showing locations of Samplings of Didymosphenia Geminata
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