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NIMBioS Seminar Series

In conjunction with the interdisciplinary activities of the National Institute for Mathematical and Biological Synthesis (NIMBioS), a seminar series on topics in mathematical biology will be hosted at NIMBioS every other Tuesday at 3:30 p.m. (unless otherwise noted) in the Hallam Auditorium, Room 206, Claxton Building, 1122 Volunteer Blvd. Seminar speakers will focus on their research initiatives at the interface of mathematics and many areas of the life sciences. Light refreshments will be served in Room 205 beginning 30 minutes before each talk. Faculty and students from across the UT community are welcome to join us.

H. Rajakaruna photo.

Speaker: Dr. Harshana Rajakaruna, Postdoctoral Fellow, Microbiology, Univ. of Tennessee

Time/Date: Tuesday, November 21, 2017, 3:30 p.m.*

Location: Room 206, Claxton Building, 1122 Volunteer Blvd.

Topic: Effect of yearly temperature cycles on species richness and population fitness: Insights from marine copepods

Abstract: Species richness (α-diversity) and population fitness (intrinsic growth rate) of fast-maturing marine copepods are generally explained as functions of ambient temperature. However, such explanations commonly take into account the long-term average sea temperatures. Yet, sea temperatures fluctuate yearly and quite dramatically in some marine regions. We will illustrate how large amplitudes of yearly temperature cycles could reduce both species richness and population fitness of marine copepods resulting from reduced generation times. These reductions can be explained by Jensen's inequality, which relates the value of a concave function of an integral to the integral of the concave function. Scientific cruise survey data supports our theoretical model predictions. The study leads to the question whether the gradient of the amplitudes of temperature cycles, between habitats with similar yearly mean temperatures, ecological and environmental conditions, influences a class of fast-maturating copepods to colonize new habitats and increase species richness. The study also gives insights into range-expansion and diversity of species in the presence of a general rise in sea temperatures with changes in the degree of their fluctuations.

Dr. Harshana Rajakaruna is a mathematical biologist currently working as a postdoctoral research associate in the Department of Microbiology at the University of Tennessee, Knoxville. His research focuses on modeling the dynamics of T-cell responses to malaria parasites. He has a Ph.D. in mathematical ecology from the University of Alberta and a master’s degree in statistical methods in fisheries from the University of Newfoundland. He also has a master’s degree in natural resource management and environmental economics and a bachelor’s degree in mathematics from the University of Peradeniya. He was a researcher at the Mathematical Biology Unit, OIST University of Japan, an NSERC Visiting Fellow at Fisheries and Oceans Canada, and a Senior Program Officer at the International Union for the Conservation of Nature.

*Join us for refreshments at 3 p.m.

Seminar Flyer (pdf)

For more information about this and other NIMBioS Seminars, visit

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NSF logo. NIMBioS is sponsored by the National Science Foundation through NSF Award #DBI-1300426, with additional support from The University of Tennessee, Knoxville. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.
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