Michele Guannel

Contact information

After receiving her Ph.D. in 2012, Michele joined the Center for Microbial Oceanography: Research and Education (C-MORE) as a Marine Science Educator.  You may contact her at mguannel {AT} hawaii.edu.


  • B.A. Smith College magna cum laude with Highest Honors in Biological Sciences, 1997.
  • Member of Sea Education Association’s SEA Semester, 1996.
  • M.S. University of Washington, Biological Oceanography, 2007.
  • Ph.D. University of Washington, Biological Oceanography, 2012.


 Research: two perspectives

~Oceans and human health~

 My research contributes to the Pacific Northwest Center for Human Health and Ocean Studies, a multidisciplinary collaboration that began at the University of Washington in 2004. A group of oceanographers, public health researchers, and other scientists, we seek to understand one type of harmful algal bloom that occurs in Washington State waters and worldwide. Marine diatoms of the genus Pseudo-nitzschia produce domoic acid, which acts as a neurotoxin in higher trophic level organisms.  Domoic acid causes Amnesic Shellfish Poisoning (ASP) in humans, and neurological disorders and death in many marine organisms, such as birds and sea lions. Domoic acid outbreaks have been documented along the Pacific Coast of Washington since the early 1990s, and more recently in Puget Sound in 2003 and 2005.

Under which conditions do Pseudo-nitzschia produce domoic acid?  Can we apply our understanding of Pseudo-nitzschia distribution and toxigenicity to “forecast” domoic acid outbreaks?  These are two of the broad questions that drive this research.

In 2008, I was awarded an Oceans and Human Health Initiative (OHHI) Pre-Doctoral Traineeship.  The OHHI Traineeship program seeks to develop scientists who communicate across diverse disciplines and direct their research to optimize impacts of the ocean upon human health and well-being.

~Microbial biogeography~

The distribution of organisms is influenced by historical and present-day responses to their environment, whereby environment is defined in terms of physical and chemical features and interactions with other organisms.  I am most fascinated by the “biological environment” that becomes, at any time, ecologically important for a species or group of organisms. I am interested in biogeography from the micro to global scales. How do individual phytoplankton cells create environments that enrich for specific types of bacteria?  Are any phytoplankton truly cosmopolitan, and if so, which factors enable this amazing level of ecological success?

Research: specific projects

~Interactions between bacteria and Pseudo-nitzschia~

Previous laboratory research (e.g. Bates et al. 1995) revealed that, when bacterial isolates are added to Pseudo-nitzschia multiseries cultures, the diatom produces higher levels of domoic acid.  However, the nature of this interaction is not well characterized. To better understand associations between bacteria and Pseudo-nitzschia, I used 16S rDNA sequencing and Automated Ribosomal Intergenic Spacer Analysis (ARISA; a community fingerprinting technique) to characterize bacterial communities coexisting with 18 Pseudo-nitzschia cultures, representing five species.  Bacterial community composition differed significantly according to Pseudo-nitzschia species and toxigenicity.

These findings could suggest that bacterial communities are influenced by domoic acid or other species-specific features of the Pseudo-nitzschia“phycosphere.”

~Community composition of toxigenic Pseudo-nitzschia blooms & Pseudo-nitzschia biogeography~

Compared to our understanding of harmful Pseudo-nitzschia blooms in the Northern Hemisphere, considerably fewer studies describe the distribution and toxigenicity of Pseudo-nitzschia blooms throughout the Southern Hemisphere.  In 2007, I surveyed Pseudo-nitzschia communities and domoic acid levels across the South Atlantic Ocean and northern Benguela Upwelling Zone. I am applying Pseudo-nitzschia ARISA (Hubbard et al. 2008), among other methods, to investigate the composition of these Pseudo-nitzschia communities in relation to known biogeography of the genus.



Teaching is one of my favorite things to do!

~Teaching and community service positions~

  • Biology and chemistry tutor, Smith College, 1996-1997.
  • AmeriCorps Member, National Civilian Community Corps, Perry Point, MD, 1997-1998. I tutored sixth graders (Baltimore, MD) and completed other community service projects throughout the northeastern US.
  • Greenfield AmeriCorps Program Member, Greenfield, MA, 1998-1999. I tutored and mentored middle school students and facilitated extracurricular art and service learning programs for middle and high school age youth.
  • Independent tutor for middle and high school students, Eugene, OR, 1999-2001.
  • Mentor, Seattle Girls’ School, 2006-2009.
  • Various outreach activities, University of Washington, 2007-present.  I am particularly interested in outreach to groups underrepresented in the sciences, in order to increase the diversity of our field.

~Teaching assistant positions at UW~

  • OCN 430 Biological Oceanography (undergraduate level), Autumn 2005.
  • OCN 102 The Changing Oceans, Winter 2010.
  • OCN 101 Survey of Oceanography, Spring 2011.
  • OCN 535 Biological Oceanography (graduate level), Autumn 2011.
  • BIOL 250 Marine Biology, Summer 2012.

~Mentorship of undergraduate researchers~

  • Gwendolynn Hannam, 2007-2008.  Phytoplankton and bacterial culturing.
  • Diana Haring, 2008-2010.  Phytoplankton microscopy and molecular methods.



Guannel, M.L., Horner-Devine, M.C., and Rocap, G.  2011.  Bacterial community composition differs with species and toxigenicity of the diatom Pseudo-nitzschia.  Aquatic Microbial Ecology 64: 117-133.  

Erdner, D.L., Dyble, J., Parsons, M.L., Stevens, R.C.,  Hubbard, K.A., Wrabel*, M.L., Moore, S.K., Lefebvre, K.A., Anderson, D.M., Bienfang, P., Bidigare, R.R., Parker, M.S., Moeller, P., Brand, L.E., and Trainer, V.L. 2008. Centers for Oceans and Human Health: a unified approach to the challenge of harmful algal blooms. Environmental Health 7:S2.

Wrabel*, M.L. and Peckol, P. 2000. Effects of bioremediation on toxicity and chemical composition of No. 2 fuel oil: growth responses of the brown algaFucus vesiculosusMarine Pollution Bulletin 40(2): 135-139.

Wrabel*, M.L.  1997.  Effects of bioremediation on physiological responses of the macroalgae Ascophyllum nodosumFucus vesiculosus and Laminaria saccharina exposed to No. 2 fuel oil.  Undergraduate Honors Thesis. Smith College Department of Biological Sciences.

* former surname: Wrabel