George McManus

(Ph.D., SUNY Stony Brook) Professor of Marine Sciences

I study zooplankton, specifically the single-celled protozoans that are responsible for most of the consumption in planktonic food webs. These organisms, which are comprised principally of a variety of flagellates and ciliates, can grow rapidly and have high metabolic rates in general. They form important links in the food web between microbial producers and multicellular organisms such as copepods and fish.

My current research projects focus on two questions related to marine protozoa: (1) What is the role of ciliate “mixotrophy” ( a metabolic strategy that involves both feeding and photosynthesis using chloroplasts from ingested prey) in coastal food webs? This project involves mainly laboratory cultivation of ciliates isolated from the sea and tracer experiments using radioactive and stable isotopes of C and N to measure metabolic rates, and (2) How much intra- and interspecific genetic diversity is there among planktonic ciliates in nature? This project requires both field sampling and cultivation of ciliates, and aims to study diversity on scales ranging from weekly changes at a single location to global biogeography. In collaboration with colleagues at Smith College in Massachusetts, my lab uses molecular tools to create species and community “fingerprints” of ciliates. We can then make comparisons with other species and communities in different parts of the world. For the future, I plan to use other molecular methods to study growth rates and other metabolic processes in marine protozoa. For more information, visit my lab webpage at

Research Projects

Diversity and biogeography of marine oligotrich and choreotrich ciliates – National Science Foundation

Carbon and Nitrogen acquisition and cycling in heterotrophic and mixotrophic ciliates – National Science Foundation

Monitoring Mesozooplankton and Microzooplankton in Long Island Sound, National Coastal Assessment – Connecticut Department of Environmental Protection

Foodweb Support for the Threatened Delta Smelt and other Estuarine Species in Suisun Bay and the Western Sacramento-San Joaquin Delta – CALFED Bay-Delta Program

Oceanography Student

Susan Smith – Ph.D. Student

Oceanography Alumni

Katharine (Katie) Haberlandt – M.Sc. 2007

Stacey McLeroy – M.Sc. 1997, Ph.D. 2002

Carol Rosetta – M.Sc. 2002

Don Schoener – Ph.D. 2013

Former Postdoctoral Fellows

Ewelina Rubin

Luciana Santoferrara


More publications and some reprints can be viewed at

York, JK, GB McManus, WJ Kimmerer, AM Slaughter, and TR Ignoffo. 2014. Trophic links in the plankton in the low salinity zone of a large temperate estuary: top-down effects of introduced copepods.  Estuaries and Coasts 37:576€“588. doi:10.1007/s12237-013-9698-9.

Grattepanche, J-D, L Santoferrara, J Andrade, AM Oliverio, GB McManus, and LA Katz. 2014. Distribution and diversity of oligotrich and choreotrich ciliates assessed by morphology and by DGGE in temperate coastal waters. Aquat. Microb. Ecol. 71:211-221. doi:10.3354/ame01675

Santoferrara, L, J-D Grattepanche, LA Katz, and GB McManus. 2014. Pyrosequencing for assessing diversity of eukaryotic microbes: analysis of data on marine planktonic ciliates and comparison with traditional methods.  Environ. Microbiol. DOI: 10.1111/1462-2920.12380

Grattepanche, J-D, L Santoferrara, GB McManus, and LA Katz. 2014. Diversity of diversity: conceptual and methodological differences in biodiversity estimates of eukaryotic microbes as compared to bacteria. Trends in Microbiology 22:432-437. DOI: 10.1016/j.tim.2014.04.006

Santoferrara, LF, S Guida, H Zhang, and GB McManus. 2014. De novo transcriptomes of a mixotrophic and a heterotrophic ciliate from marine plankton. PLOS One DOI: 10.1371/journal.pone.0101418

Contact Information