University of Pittsburgh Department of Biological Sciences presents:
2019 Spring Seminar Series
Dr. Nelson Hairston Jr.
Cornell University
“Eco-Evolutionary Dynamics meets Hydrodynamics: Linking internal waves and internal phosphorus-loading to rapid Daphnia evolution via cyanobacterial blooms"
In this talk I will show for a shallow lake, in the Finger Lakes region of New York State, how accumulation of phosphorus in anoxic bottom water, due to chemical reducing conditions, is transported to the epilimnion by high-amplitude internal waves travelling along the thermocline, leading to a significant late-summer cyanobacterial phytoplankton bloom. This is a particularly timely observation given the management challenges driven by the increasing prevalence of HABs (Harmful Algal Blooms comprised of cyanobacteria) in lakes regionally and world-wide. I then show for a similar lake in the same geographic region how such a late-summer cyanobacterial bloom selects for evolution of distinct genotype frequencies in a major phytoplankton consumer (Daphnia) with clones that grow best in spring “good food” phytoplankton dominating in spring, and genotypes that are relatively insensitive to summer “bad food” cyanobacteria dominating in late summer. Thus my talk moves from redox dynamics, to internal phosphorus loading, to hydrodynamics, to phytoplankton composition, to evolution of a major planktonic consumer. I end with a speculation that Daphnia evolution of food tolerance within a single season may feedback on phytoplankton succession altering classic ecological consumer resource dynamics.
Monday, March 18, 2019
169 Crawford Hall
11:00 A.M.
10:50 A.M. refreshments
Host: Dr. Martin Turcotte