1. Algal Toxin Production in Arid-Land Reservoirs David Walker University of Arizona NSF/UA Water Quality Cen ter

6. http://walter.arizona.edu/ Drought and Wildfire

7. Rodeo-Chedeski Fire The largest wildfire in Arizona recorded history began on June 18 th, 2002. Burned almost 500,000 acres in the White Mountains to the north and east of Phoenix. Several major drainages to the Salt River were within the burn area.

10. Pre- and Post-fire Nutrient Loading

11. Increasing Hypolimnetic Anoxia in Roosevelt

12. Primary Production in Roosevelt

13. Primary Production in Apache, Canyon, and Saguaro

14. History of Algal Toxins in Salt River Reservoirs August 2000 – Large die-off of Corbicula fluminea in the riverine zone of Saguaro reservoir. Found over 140 μg/L of anatoxin-a in aqueous samples.

16. Cylindrospermopsis raciborskii

17. Fish Kills First major fish kill occurred in Apache in March of 2004. Subsequent fish kills occurred in Canyon, Saguaro, and again in Apache throughout the spring and early summer. Multiple species involved.

19. A major fish kill occurred in the riverine portion of Saguaro on 6/10/04. Smaller fish (e.g., threadfin shad) were noticed dead or moribund in Canyon on 6/9/04.

21. Subsequent fish kills, usually beginning in riverine sections, in winter/spring of 2004, 2005, 2006, and decreasing in 2007. No early indicators of fish kill activity this year. Salinity decreased in reservoirs due to adequate winter precipitation and snowmelt.

22. Prymnesium parvum http://www.nies.go.jp/biology/mcc/images/100images/nies- 1397.jpg

24. From Sasaki et al. 2006. Causes mass hemolysis of red blood cells. Structurally similar to brevotoxin. Mass in excess of 1400 AMUs. Structure would appear to make cell entry difficult..

25. Fish toxicosis difficult to explain. No studies showing any significant correlation between concentrations of prymnesin in the water to fish toxicosis. Likely a toxic fraction.

26. Fractionation and Quantification of Prymnesin Toxins JoAnn Burkholder (NCSU), Paul Zimba (USDA-ARS) –Grow unialgal cultures in bulk –Concentrate cell biomass and dissolved organics. –Send cell pellets and SPE material for toxin extraction/assessment.

27. Peter Moeller (NOAA) –Biochemical fractionation, toxin class identification, development of toxin bioassay(s). –Identification of toxin/development of method for toxin assessment

28. Potential Factors for Algal Toxin Production in Reservoirs Changing nutrient ratios due to watershed disturbance.

29. Drought/Climate Change

30. Summary Different types of toxins can be produced by reservoirs due to changing environmental conditions. Toxin production and presence of species capable of producing toxins are poorly correlated. Toxin production of any given species also depends on as-of-yet ill-defined environmental triggers. In connected systems, differing nutrient ratios between upstream-downstream reservoirs may trigger toxin production. Massive watershed disturbance can result in favoring certain toxin-producing species over others.

31. Questions?