Spring Chemistry 501 Seminar
UT Host: Dr. Bhavya Sharma
Speaker: Dr. M.L. Myrick
Professor/Physical and Theoretical Analytical/Environmental/Forensics/Materials/Spectroscopy Departments of Chemistry & Biochemistry
University of South Carolina
Title: “An Ocean Full of Small Green Things: Inroads on the Nanophytoplankton Classification Problem”
Ocean primary production accounts for about 50% of all carbon cycling in the environment, and 90% of this is from phytoplankton. Most of the carbon captured by phytoplankton photosynthesis is eventually returned to the atmosphere, but a portion is exported from the biosphere as sediment that may ultimately be sequestered for geological timescales. An important question is: how much? This answer depends on the types of phytoplankton that dominate their community structure. Satellites are quite good at visualizing patterns of chlorophyll in the world’s oceans, but not good at distinguishing the types of phytoplankton that are present. There are at least many thousands, and perhaps millions, of different species of phytoplankton, falling into 13 broad classes distinguishable by pigmentation. Diatoms (Bacillariophyceae) and some other types, for instance, frequently have heavy inorganic constituents that tend to cause them to sink out of the photic zone when they die, decreasing the likelihood that they will be immediately consumed and their carbon returned to the atmosphere by respiration.
The determination of community structure is challenging. We are not aware of any location on earth for which a complete community structure has ever been obtained, even for a single point in time. Most studies of species in nature are of those that are readily distinguished by their visual appearance, with the other components of the community structure going unrecorded. The most advanced flow cytometric tool for the automatic study of nanophytoplankton populations (i.e., 2-20 µm cell size) lumps a majority of the nanophytoplankton it observes into a single class called “mix” - which is a catch-all for “small green things”.
We have worked on the problem of distinguishing among classes of nanophytoplankton using fluorescence excitation methods. Part of our work involved understanding whether single cells could be distinguished by this method. Part of our work has been conceptual: how to deal with a calibration set that can never be completed, only expanded. Part of our work has been to understand the best selection of optical filters for improving discrimination between species. And another portion of our work has been to understand how environmental factors influence our ability to distinguish nanophytoplankton, and how rapidly they respond to changes in conditions. This presentation will give an overview of all of these aspects of our work over the past few years, with a special focus on work completed in the past 12 months.
Michael (Micky) Myrick received his Ph.D. from New Mexico State University in 1988 and was a postdoctoral associate of S. Michael Angel at Lawrence Livermore National Laboratory from 1989-90. He was a staff member at LLNL from 1990-91, and has been a member of the Department of Chemistry and Biochemistry at the University of South Carolina from 1991-present. He is the author of 170+ publications and 33+ issued patents. His work in multivariate optical computing lead via a startup to the ICE sensor system commercialized by Halliburton Energy Services for petroleum exploration and carbon sequestration, in use worldwide. His work has featured on the covers of Analytical Chemistry, Applied Spectroscopy, Laser Focus World and the Reservoir Innovations Technical Journal. His work in infrared chemical imaging and adsorption thermography was publicized on CNN, Fox, NPR Science Friday, SC Radio Network, Popular Science, and elsewhere. He received the Outstanding SC Chemist Award from the SC Section of the ACS and was named a Fellow of the Society for Applied Spectroscopy in 2018. As an educator, Micky teaches general chemistry, both physical chemistry laboratory courses, and a graduate course in molecular spectroscopy. He has published 5 papers on new spectroscopy experiments for physical chemistry laboratories in the Journal of Chemical Education, and has received several teaching awards at USC, including the 2013 Michael J. Mungo undergraduate teaching award and the SC Honors College Outstanding Professor of Science award.
Thursday, February 28 at 3:45pm to 5:00pm
Buehler Hall, 555
1420 Circle Drive, Knoxville, TN 37996