RT Journal Article
SR Electronic
T1 Temperature selection drives evolution of function-valued traits in a marine diatom
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 167817
DO 10.1101/167817
A1 Daniel R. O’Donnell
A1 Carolyn R. Hamman
A1 Evan C. Johnson
A1 Christopher A. Klausmeier
A1 Elena Litchman
YR 2017
UL http://biorxiv.org/content/early/2017/07/24/167817.abstract
AB Rapid evolution in response to environmental change will likely be a driving force determining the distribution of species and the structure of communities across the biosphere in coming decades. This is especially true of microorganisms, many of which may be able to evolve in step with rising temperatures. An ecologically indispensable group of microorganisms with great potential for rapid thermal adaptation are the phytoplankton, the diverse photosynthetic microbes forming the foundation of most aquatic food webs. We tested the capacity of a globally important phytoplankton species, the marine diatom Thalassiosira pseudonana, for rapid evolution in response to temperature. Evolution of replicate populations at 16 and 31°C for 350-450 generations led to significant divergence in several traits associated with T. pseudonana’s thermal reaction norm (TRN) for per-capita population growth, as well as in its competitive ability for nitrogen (commonly limiting in marine systems). Of particular interest were evolution of the optimum temperature for growth, the upper critical temperature, and the derivative of the TRN, an indicator of potential tradeoffs resulting from local adaptation to temperature. This study offers a broad examination of the evolution of the thermal reaction norm and how modes of TRN variation may govern a population’s long-term physiological, ecological, and biogeographic response to global climate change.