Wednesday, August 14, 2019: 1:30 PM
M111, Kentucky International Convention Center
ABSTRACT WITHDRAWN
Stephen J. Beckett1, David Demory
1, Ashley R. Coenen
1, John R. Casey
2, Christopher L. Follett
3, Mathilde Dugenne
2, Paige E. Connell
4, Michael C. G. Carlson
5, Sarah K. Hu
6, Samuel T. Wilson
2, Daniel Muratore
1, Angie K. Boysen
7, Matthew J. Harke
8, Elaine Luo
2, Rogelio Rodriguez
1, Shengyun Peng
1, E. Virginia Armbrust
7, David A. Caron
9, Edward F. DeLong
10, Sonya T. Dyhrman
8, Anitra E. Ingalls
7, David M. Karl
11, Debbie Lindell
12, Benjamin A. S. Van Mooy
6, Jonathan P Zehr
13, Mick Follows
14, Angelicque E. White
2, Francois Ribalet
7 and Joshua S. Weitz
15, (1)Georgia Institute of Technology, Atlanta, GA, (2)University of Hawai’i at Mānoa, Honolulu, HI, (3)Massachusetts Institute of Technology, Boston, MA, (4)San Diego Mesa College, San Diego, CA, (5)Technion - Israel Institute of Technology, Haifa, Israel, (6)Woods Hole Oceanographic Institution, Woods Hole, MA, (7)University of Washington, Seattle, WA, (8)Columbia University, New York, NY, (9)University of Southern California, CA, (10)Department of Biological Engineering & Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, (11)Oceanography, University of Hawai'i at Manoa, Honolulu, HI, (12)Technion - Israel Institute of Technology, Haifa, Israel, (13)Department of Ocean Sciences, UC Santa Cruz, Santa Cruz, CA, (14)Earth, Atmosphere and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, (15)School of Biology, School of Physics, Georgia Institute of Technology, Atlanta, GA
Stephen J. Beckett, Georgia Institute of Technology;
David Demory, Georgia Institute of Technology;
Ashley R. Coenen, Georgia Institute of Technology;
John R. Casey, University of Hawai’i at Mānoa;
Christopher L. Follett, Massachusetts Institute of Technology;
Mathilde Dugenne, University of Hawai’i at Mānoa;
Paige E. Connell, San Diego Mesa College;
Michael C. G. Carlson, Technion - Israel Institute of Technology;
Sarah K. Hu, Woods Hole Oceanographic Institution;
Samuel T. Wilson, University of Hawai’i at Mānoa;
Daniel Muratore, Georgia Institute of Technology;
Angie K. Boysen, University of Washington;
Matthew J. Harke, Columbia University;
Elaine Luo, University of Hawai’i at Mānoa;
Rogelio Rodriguez, Georgia Institute of Technology;
Shengyun Peng, Georgia Institute of Technology;
E. Virginia Armbrust, University of Washington;
David A. Caron, University of Southern California;
Edward F. DeLong, Massachusetts Institute of Technology;
Sonya T. Dyhrman, Columbia University;
Anitra E. Ingalls, University of Washington;
David M. Karl, University of Hawai'i at Manoa;
Debbie Lindell, Technion - Israel Institute of Technology;
Benjamin A. S. Van Mooy, Woods Hole Oceanographic Institution;
Jonathan P Zehr, UC Santa Cruz;
Mick Follows, Massachusetts Institute of Technology;
Angelicque E. White, University of Hawai’i at Mānoa;
Francois Ribalet, University of Washington;
Joshua S. Weitz, Georgia Institute of Technology
Background/Question/Methods Prochlorococcus is the most abundant photosynthetic organism on Earth and plays a key role in oligotrophic oceans such as the North Pacific Subtropical Gyre (NPSG). Theory suggests that light availabilty and size-dependent processes are core drivers of growth and mortality in oceanic ecosystem communities. A key question is how much viruses contribute to the mortality of phytoplankton relative to grazers. Motivated by timeseries measurements made via Lagrangian sampling in the NPSG we assess population dynamics of Prochloroccocus, micrograzers and viruses over daily timesecales. To understand this dataset we developed a size-structured dynamical model of Prochlorcoccus cells whose growth is light dependent and are subject to infection by viruses and to ingestion by grazers. Using our process-based model we are able to evaluate how in situ ecological rhythms compare with in silico ecological rhythms. In particular, we assess the strength of virus-induced mortality relative to grazing mortality in the NPSG and explore the sensitivity of this balance with respect to model parameterization.
Results/Conclusions
Our study provides a methodology for bridging community-level data from a variety of sources with dynamical modelling to explain ecosystem processes on short-term daily timescales. Preliminary results show that our model is capable of recapitulating ecosystem dynamics observed in the NPSG. Within this system, our model suggests that Prochlorococcus mortality peaks during the night and that grazing mortality is much greater than viral-induced mortality. Whilst phytoplankton growth is light-driven, we suggest that NPSG data is best fit by a model in which grazing and infection processes are also driven in a diel manner. More generally, we investigate potential drivers of the differential importance of viral lysis relative to grazer mortality and assess potential variations of population dynamics on daily timescales. Our results help drive our understanding of the dynamics, processes and the functioning of oceanic ecological communities across daily timescales.
