1. Clancy Brown William Smith College Rocky Mountain Biological Lab Mentor: Brad W. Taylor Effect of the nuisance diatom Didymosphenia geminata on invertebrates in the East River

2. What is Didymo? Image: Sarah Kiemle, Michigan Tech University Other diatom species; growing attached to stalk Didymo stalk Didymo cells

4. Blooms of Rock Snot? Map: Sarah Spaulding, USGS

5. Questions (1)Does D. geminata alter the composition and abundance of stream invertebrates? (2) Does D. geminata affect the growth rate of stream invertebrates?

7. Removal Plots Upstream Downstream 8 2 3 4 5 6 7 1 D D D D D D D D

8. I’m good at removing didymo!

9. Three invertebrate species showed habitat selection E. longimanus Chironomidae Hesperoperla pacifica

10. Didymo has no effect on species richness

11. Two Experiments in the East River: Growth Chambers Baetis spp N = 6 chambers/treatment Epeorus longimanus N = 9 chambers/treatment

12. Epeorus longimanus shows a trend towards slower growth rate in Didymo

13. Didymo has no effect on the growth rate of Baetis spp

14. Summary: Effect of D. geminata on stream invertebrates (1)Composition and abundance -More Chironomidae and stoneflies (Hesperoperla), but fewer E. longimanus in D. geminata treatment -No difference in species richness (2)Growth rate -A trend for slower growth in E. longimanus -No significant effect on Baetis spp

15. Acknowledgements Brad W. Taylor The “Benthettes” The National Science Foundation Rocky Mountain Biological Laboratory