Boulder, GRAD STUDENT
 The benthic, mat-forming diatom Didymosphenia geminata has the unique ability to produce large amounts of algal biomass under oligotrophic conditions in cold, fast flowing streams and rivers. This presents an ecological paradox that challenges our current understanding of stream ecosystem dynamics. Our understanding of the drivers of D. geminata ecology is still limited. Here we present a conceptual model for the blooming behavior and persistence of this species to advance scientific understanding of strategies for life in fast flowing oligotrophic waters and support the design of future research and mitigation measures for nuisance algal blooms. The conceptual model is based on a synthesis of data and ideas from a range of disciplines including hydrology, geomorphology, biogeochemistry, and ecology. The conceptual model highlights the role of water chemistry, river morphology, and flow thresholds in defining the habitat window for D. geminata. We propose that bed disturbance is a primary control on accumulation and persistence of D. geminata and that the removal threshold can be determined by synthesizing site-specific information on hydrology and geomorphology. Further, we propose that a key to understanding the didymo paradox is the separation of cellular reproduction
Cullis J.D.S., Gillis C-A, Bothwell M.L, Kilroy C, Packman A. and Hassan M. (2012): A conceptual model for the blooming behavior and persistence of the benthic mat-forming diatom Didymosphenia geminata in oligotrophic streams. JGR-Biogeosciences. DOI: 10.1029/2011JG001891
This Paper/Book acknowledges NSF CZO grant support.