Orlando Sarnelle, Ph.D.

Orlando Sarnelle


163A Natural Resources


Area of Expertise: Biological limnology; trophic interactions; plankton ecology; water quality; nuisance algal blooms; exotic species; population and community ecology


Ph. D., University of California, Santa Barbara.
M. S., University of Massachusetts, Amherst.
B. S., Rutgers University.


I am a limnologist and ecologist with relatively broad interests. A major theme in my research has been to understand the roles that interactions among aquatic populations (primarily phytoplankton and zooplankton) play in population and community dynamics within lakes. I am also interested in how these interactions impact the overall functioning of aquatic ecosystems. The approach that I take to questions relies very heavily on field experimentation, and I am very interested in assessing how well such experiments inform us about processes in nature.

Lately, we have been focusing most of our research attention on the ecology of cyanobacteria, the most important group of freshwater phytoplankton with respect to degradation of water quality in lakes and reservoirs. Harmful blooms of freshwater phytoplankton (so-called HABs) nearly always involve cyanobacteria, which produce a variety of compounds with acute and chronic toxicity to humans and other terrestrial animals.

I am a member of the Ecology, Evolutionary Biology & Behavior program and the Center for Water Sciences at MSU, and an adjunct faculty member at the W. K. Kellogg Biological Station. I am also a member of the Editorial Board of Ecology/Ecological Monographs.

Research Interests

Interactions between Daphnia and cyanobacteria in eutrophic lakes - We continue to extend previous counter-intuitive results regarding the impact of Daphnia grazing on supposedly-inedible cyanobacteria (blue-green algae). This research has implications for the control of nuisance cyanobacteria in productive lakes. We have demonstrated that Daphnia pulicaria collected from lakes with high concentrations of cyanobacteria are better able to grow on a diet of 100% toxic cyanobacteria than individuals of the same species collected from lakes with little or no cyanobacteria.  More recently, we demonstrated in field experiments that the ability of a Daphnia population to supress toxic blooms of phytoplankton is largely driven by the presence of Daphnia genotypes that are tolerant of cyanobacterial toxins.  Our recent work is a collaborative effort with scientists at Auburn University.

Zebra mussels and toxic algal blooms in lakes - We are investigating the link between zebra mussel invasion and the incidence and severity of cyanobacterial blooms in lakes. We have conducted a series of large-scale field experiments to determine the functional relationship between zebra mussel abundance and phytoplankton biomass and species composition.  We have demonstrated that zebra mussels increase the abundance of Microcystis aeruginosa, a toxic phytoplankton species, and the concentration of microcystin toxin, in lakes with low to moderate nutrient levels.  In direct contrast, zebra mussels suppress this same species when nutrient levels are increased.  These findings have potentially radical implications for both the field of limnology and for the management of water quality, although the precise mechanisms driving the effect reversal remain to be uncovered.  We have collaborated with scientists at the Great Lakes Environmental Research Laboratory (NOAA) on zebra mussel-Microcystis interactions.

High Sierra Experimental Lakes - We are examining how the removal of an exotic predator influences population, community and ecosystem dynamics at the whole-lake scale. High-elevation lakes in the Sierra were once fishless, with a unique set of planktonic and benthic species that are driven locally extinct by the stocking of exotic trout. From a set of whole-lake manipulations, we have demonstrated that the probability of recovery from local extinction is much lower for sexually-reproducing copepods than for asexually-reproducing Daphnia. We have also demonstrated that mate limitation (an Allee effect) reduces the re-establishment probability of sexually-reproducing copepods, despite the presence of viable resting eggs in the sediment.  This work represents a collaboration between MSU and the Sierra Nevada Aquatic Research Laboratory (UCSB).

Meta-analysis - I was part of a working group sponsored by the National Center for Ecological Analysis and Synthesis examining issues regarding the application of meta-analysis to ecological questions. Meta-analysis, the quantitative synthesis of published experimental results, holds great promise for prediction and generality, but the techniques used in classical meta-analysis require conceptual modification before being applied in ecology. A recent meta-analysis we conducted uncovered consistent evidence of a Type 3 functional response in Daphnia, which we suspect may extend to other filter feeders.

Courses Taught

Ecological Problem Solving (Spring), FW364 

Water and the Environment, ISP217

Water and the Environment Laboratory, ISP217L

Selected Publications

White, J. D. and O. Sarnelle.  2014.  Size-structured vulnerability of the colonial cyanobacterium, Microcystis aeruginosa, to grazing by zebra mussels (Dreissena polymorpha).  Freshwater Biology 59:514-525.

Horst, G. P., O. Sarnelle, J. D. White, S. K. Hamilton, R. B. Kaul and J. D. Bressie.  2014. Nitrogen availability increases the toxin quota of a harmful cyanobacterium, Microcystis aeruginosa.  Water Research 54:188-198.

Chislock, M. F., O. Sarnelle, B. Olsen, E. Doster, and A. E. Wilson.  2013.  Large effects of consumer offense on ecosystem structure and function.  Ecology 94: 2375-2380.

Chislock, M. F., O. Sarnelle and A. E. Wilson.  2013.  Do high concentrations of microcystin prevent Daphnia control of phytoplankton?  Water Research 47: 1961-1970.

Vanderploeg, H. A., A. E. Wilson, T. H. Johengen, J. Dyble, O. Sarnelle, Liebig, J. R., Robinson, S. D., Horst, G. P.  2013.  The role of selective grazing by dreissenid mussels in promoting toxic Microcystis blooms and other changes in phytoplankton composition in the Great Lakes.  Pages 509-524 in: T. F. Nalepa and D. W. Schloesser, editors, Quagga and Zebra Mussels: Biology, Impacts, and Control, Second Edition. CRC Press, Boca Raton, FL.

Sarnelle, O., J. D. White, G. P. Horst and S. K. Hamilton.  2012.  Phosphorus addition reverses the effect of zebra mussels (Dreissena polymorpha) on the toxic cyanobacterium, Microcystis aeruginosa.  Water Research 46: 3471-3478.

White, J. D., A. E. Wilson, R. B. Kaul, L. B. Knoll and O. Sarnelle. 2011. Large variation in vulnerability to grazing within a population of the colonial phytoplankter, Microcystis aeruginosa. Limnology and Oceanography 56:1714-1724.

Wilson, A. E., R. B. Kaul and O. Sarnelle. 2010. Growth rate consequences of coloniality in a harmful phytoplankter. PLoS ONE 5(1): e8679. doi:10.1371/journal.pone.0008679. 

Sarnelle, O., J. Morrison, R. Kaul, G. Horst, H. Wandell and R. Bednarz. 2010. Citizen monitoring: testing hypotheses about the interactive influences of eutrophication and mussel invasion on a cyanobacterial toxin in lakes. Water Research 44:141-150.

Carlsson, N. O. L., O. Sarnelle and D. Strayer. 2009. Native predators and exotic prey – an acquired taste? Frontiers in Ecology and the Environment.

Hamilton, S. K., D. A. Bruesewitz, G. P. Horst, and O. Sarnelle. 2009. Precipitation of phosphorus with calcite as a negative feedback to lake eutrophication. Canadian Journal of Fisheries and Aquatic Sciences 66:321-342.

Kramer, A. and O. Sarnelle. 2008. Limits to genetic bottlenecks and founder events imposed by the Allee effect. Oecologia 157:561-569. 

Knapp, R. A. and O. Sarnelle. 2008. Recovery after local extinction: factors affecting re-establishment of alpine lake zooplankton after removal of nonnative fish. Ecological Applications 18:1850-1859. 

Kramer, A. O. Sarnelle and R. A. Knapp. 2008. Allee effect limits colonization success of sexually reproducing zooplankton. Ecology 89:2760-2769. 

Sarnelle, O. and A. E. Wilson. 2008. Type III functional response in Daphnia. Ecology 89:1723-1732. 

Knoll, L. B., O. Sarnelle, S. K. Hamilton, C. E. H. Scheele, A. E. Wilson, J. B. Rose and M. R. Morgan. 2008. Invasive zebra mussels (Dreissena polymorpha) increase cyanobacterial toxin concentrations in low-nutrient lakes. Canadian Journal of Fisheries and Aquatic Sciences 65:448-455. 

Sarnelle, O. 2007. Initial conditions mediate the interaction between Daphnia and bloom-forming cyanobacteria. Limnology and Oceanography 52:2120-2127. 

Wilson, A. E., O. Sarnelle and A. Tillmanns. 2006. Effects of cyanobacterial toxicity and morphology on population growth of freshwater zooplankton: meta-analysis of laboratory experiments. Limnology and Oceanography 51:1915-1924. 

Sarnelle, O. 2005. Daphnia as keystone predators: effects on phytoplankton diversity and grazing resistance. Journal of Plankton Research 12:1229-1238. 

Sarnelle, O. and R. A. Knapp. 2005. Nutrient recycling by fish versus zooplankton grazing as drivers of the trophic cascade in alpine lakes. Limnology and Oceanography 51:2032-2042. 

Sarnelle, O., and A. E. Wilson. 2005. Local adaptation of Daphnia pulicaria to toxic cyanobacteria. Limnology and Oceanography 50:1565-1570. 

Sarnelle, O., A. E. Wilson, S. K. Hamilton, L. B. Knoll, and D. E. Raikow. 2005. Complex interactions between exotic zebra mussels and the noxious phytoplankter, Microcystis aeruginosa. Limnology and Oceanography 50:896-904. 

Wilson, A. E., O. Sarnelle, B. A. Neilan, T. P. Salmon, M. M. Gehringer and M. E. Hay. 2005. Genetic variation of the bloom-forming cyanobacterium, Microcystis aeruginosa, within and among lakes: implications for harmful algal blooms. Applied and Environmental Microbiology 71:6126-6133. 

Sarnelle, O. and R. A. Knapp. 2004. Zooplankton recovery after fish removal: limitations of the egg bank. Limnology and Oceanography 49:1382-1392. GET PDF

Sarnelle, O. 2003. Non-linear effects of an aquatic consumer: causes and consequences. American Naturalist 161:478-496. 

Wilson, A. E. and O. Sarnelle. 2002. Relationship between zebra mussel biomass and total phosphorus in European and North American lakes. Archiv für Hydrobiologie 153:339-351.

Knapp, R. A., K. R. Matthews and O. Sarnelle. 2001. Resistence and resilience of alpine lake fauna to fish introductions. Ecological Monographs 71:401-421.

Sarnelle, O. 1999. Zooplankton effects on vertical particulate flux: Testable models and experimental results. Limnology and Oceanography 44:357-370.

Osenberg, C. W., O. Sarnelle, S. D. Cooper and R. D. Holt. 1999. Resolving ecological questions through meta-analysis: goals, metrics and models. Ecology 80:1105-1117.

Downing, J. A., C. W. Osenberg and O. Sarnelle. 1999. Meta-analysis of marine nutrient-enrichment experiments: variation in the magnitude of nutrient limitation. Ecology 80:1157-1167.

Englund, G., O. Sarnelle and S. D. Cooper. 1999. The importance of data selection criteria: meta-analyses of stream predation experiments. Ecology 80:1132-1141.

Cooper, S. D., S. Diehl, K. Kratz and O. Sarnelle. 1998. Implications of scale for patterns and processes in freshwater ecology. Australian Journal of Ecology 23:27-40.

Osenberg, C. W., O. Sarnelle and S. D. Cooper. 1997. Effect size in ecological experiments: the application of biological models in meta-analysis. American Naturalist 150:798-812.

Sarnelle, O. 1997. Daphnia effects on microzooplankton: comparison of enclosure and whole-lake responses. Ecology 78:913-928.

Sarnelle, O. 1994. Inferring process from pattern: trophic level abundances and imbedded interactions. Ecology 75:1835-1841.

Sarnelle, O. 1993. Herbivore effects on phytoplankton succession in a eutrophic lake. Ecological Monographs 63:129-149.

Sarnelle, O., K. W. Kratz and S. D. Cooper. 1993. Effects of an invertebrate grazer on the spatial arrangement of a benthic microhabitat. Oecologia 96:208-218.

Sarnelle, O. 1992. Contrasting effects of Daphnia on ratios of nitrogen to phosphorus in a eutrophic, hard-water lake. Limnology and Oceanography 37:1527-1542.

Sarnelle, O. 1992. Nutrient enrichment and grazer effects on phytoplankton in lakes. Ecology 73:551-560.

Last updated: June, 2009