Biology & Paleo Environment Events

For upcoming seminars, see our calendar here.

Current Seminar Managers: Cassaundra Rose and Samuel Phelps 

Time and Location: Mondays at 12 pm, Comer Seminar Room

March 30th: Dr. Steven Smriga, Postdoctoral Researcher, MIT. Host: Andrew Juhl.

"Dissecting the Phycosphere: Upscaling Bacterial Consumption Near Individual Diatoms."


Individual phytoplankton cells create a region rich in dissolved organic matter (DOM) – the phycosphere – to which chemotactic bacteria can be attracted. As a prominent form of microscale patchiness and resource heterogeneity in the ocean, phycosphere ‘hotspots’ may have important consequences for bacterial populations and DOM dynamics. To scale up the effects of phycospheres in space and time, high resolution video microscopy and image analyses were used to dissect the chemotactic accumulation of natural bacterial populations around individual Chaetoceros affinis diatoms undergoing controlled lysis. Bacterial distributions quantified from the videos were used as input to a mathematical model which enabled predictions on the relative consumption of released DOM by motile and nonmotile bacterial populations, the ‘escape’ of DOM into bulk seawater, the partitioning of diatom DOM components by molecular size, and the growth benefits afforded to individual bacteria through consumption in the phycosphere. By directly using behavioral data to inform a model, this hybrid approach provides a blueprint for the upscaling of hotspot interactions from the microscales at which they occur to the scales at which they affect food web dynamics and ocean chemistry.

Spring 2015:

  • February 2nd: Postponed due to winter storm
  • February 9th: Dr. Todd Sowers, Senior Scientist EESI, Penn State. Host: Pratigya Polissar. "Methane Isotope Records Spanning the last 160kyr: Correlations and Conundrums."
  • SPECIAL SEMINAR February 13th @ 1 pm: Dr. Matt Bekker, Brigham Young University. Host: Brendan Buckley. "Lessons from Centennial- and Millennial-length Reconstructions of Northern Utah’s Hydroclimate from Tree Rings."
  • February 16th: open
  • February 23rd: Dr. Lidya Tarhan, Postdoctoral Researcher, Yale University. Host: Cassaundra Rose. "Protracted Development of Bioturbation through the Early Paleozoic."
  • March 2nd, 2 pm: Dr. Christa Farmer, Hofstra. Host: Mike Kaplan. “Learning from the Impacts of Superstorm Sandy: Paleotempestology on Long Island.”
  • March 9th: Dr. Carling Hay, Postdoctoral Fellow, Harvard University. Host: Maureen Raymo. "Revisiting the Past: Fingerprinting the Sources of 20th Century Global Sea-Level Rise."
  • March 16th: open/Spring Break
  • March 23rd: Dr. Ailene Ettinger, Putnam Fellow, The Arnold Arboretum of Harvard University. Host: Ben Cook. "Testing the limits: effects of climate & competition on tree ranges in a warming world"
  • March 30th: Dr. Steven Smriga, MIT. Host: Andrew Juhl. "Dissecting the Phycosphere: Upscaling Bacterial Consumption Near Individual Diatoms."
  • April 6th: Dr. Jodi Young, Postdoctoral Researcher, Princeton University. Host: Kim Popendorf. "Physiological mechanisms supporting high net primary productivity in the Western Antarctic Peninsula."
  • April 13th, 2 pm: Dr. Mrinalini Nikrad, Postdoc, Rutgers. Host: Jeff Bowman. Bacterial abundance and activity in polar marine and soil environments.
  • April 20th: Dr. Senji Lin, UConn. Host: Joaquim Goes. "Energy and nutrient strategies in dinoflagellates."
  • SPECIAL SEMINAR April 20th, 2:30 pm: Dr. Aldo Shemesh, Weizmann Institute. Host: Yoni Goldsmith.
  • April 27th: Dr. Jennifer Stanford, Drexel University. Host: Andy Juhl.
  • SPECIAL SEMINAR May 1st @ 12:15 pm: Dr. Steven Meyers. Host: Maureen Raymo. "Climate “Noise” and the Cryosphere: New Constraints on the Evolution of Ice Sheets During the Cenozoic."
  • May 4th: Dr. Suni Shah Walter, Harvard University. Host: Kim Popendorf.
  • May 11th: Dr. Jack Scheff, Postdoc, LDEO, "Does greenhouse warming dry out the continents? Lessons from theory, proxies, and models"
  • May 18th: Dr. Brad Linsley, LDEO. American Samoa coral record of S. Pacific climate
  • June 1st: Dr. Navjit Sagoo, Postdoctoral Associate, Yale University. Host: Frankie Pavia. Tentative topic: dust and cloud physics in the Pliocene

Additional talks can be seen on the

google calendar.