MULTI’OMICS INDICATE DEPTH-DISCRETE PARTITIONING OF NITROGEN METABOLISM IN A TOXIC PLANKTOTHRIX RUBESCENS BLOOM IN THE WINTER WATER COLUMN

In this study, we conducted a metagenomic+metabolomic field study to address a community concern in our own back yard: What was causing Mead’s Quarry (Knoxville, TN) to turn pink?  A case study was designed and implemented by graduate students at the University of Tennessee-Knoxville enrolled in the course-based authentic learning experience Advanced Techniques in Field Microbiology (Spring 2023). The team leveraged a $3,000 budget to conduct meaningful, depth-discrete multi ‘omics research. Metagenomic analyses and phylogenetic confirmations revealed the quarry was dominated by a bloom of the pink cyanobacterium Planktothrix rubescens. Physiochemical analyses indicated the bloom was concentrated in the cold, light-limited metalimnion, with microcystin-LR levels exceeding the U.S. EPA limit for recreational exposure. Untargeted metabolomics suggested P. rubescens communities were differentially partitioning nitrogen metabolism strategies by depth (0.5 m vs. 2.0 m). This work has revealed a previously underappreciated role of arginine biosynthesis and pyrimidine metabolism in the ecological success of P. rubescens. We subsequently provide these results as a novel ecophysiological hypothesis contributing to the proliferation of this harmful cyanobacterial bloom former in the light-limited metalimnion. Cumulatively, we reinforce the synergistic employment of multiple meta ’omics techniques is feasible on a small-scale while proving impactful on a larger-scale.

Presentation Preference: Oral

Primary Presenter: Brittany Zepernick, University of North Carolina at Chapel Hill (bnzeper95@gmail.com)

Authors:

Brittany Zepernick, University of North Carolina at Chapel Hill  (bnzeper95@gmail.com)

David Niknejad, Department of Microbiology, University of Tennessee  (dnikneja@usc.edu)

Emily Chase, Department of Microbiology, University of Tennessee  (echase2@utk.edu)

Blessing Abiodun, Department of Chemistry, University of Tennessee  (babiodun@vols.utk.edu)

Meaghan Adler, Department of Microbiology, University of Tennessee  (madler5@vols.utk.edu)

Katelyn Houghton, Department of Microbiology, University of Tennessee  (khought1@vols.utk.edu)

Jason Olavesen, Department of Microbiology, University of Tennessee  (jolavese@vols.utk.edu)

Qudus Sarumi, Department of Chemistry, University of Tennessee  (qsarumi@vols.utk.edu)

Alexander Truchon, Department of Microbiology, University of Tennessee  (atruchon@vols.utk.edu)

Jillian Walton, Department of Microbiology, University of Tennessee  (jwalto12@vols.utk.edu)

Jack Cheshire, Institute of Marine Sciences, University of North Carolina at Chapel Hill  (jcheshi@unc.edu)

Hans Paerl, Institute of Marine Sciences, University of North Carolina at Chapel Hill  (hans_paerl@unc.edu)

Justin Chaffin, F.T. Stone Laboratory and Ohio Sea Grant, The Ohio State University  (chaffin.46@osu.edu)

Gregory Boyer, Department of Chemistry, State University of New York College of Environmental Science and Forestry  (glboyer@esf.edu)

Hector Castro, Department of Chemistry, University of Tennessee  (hcastrog@utk.edu)

Shawn Campagna, Department of Chemistry, University of Tennessee  (campagna@utk.edu)

George Bullerjahn, Department of Biological Sciences, Bowling Green State University  (bullerj@bgsu.edu)

Steven Wilhelm, Department of Microbiology, University of Tennessee  (wilhelm@utk.edu)