Acclimation and adaptation of phytoplankton to changing climate

Climate change over the next century is projected to alter fundamental physical and chemical properties of the ocean including water temperature, pH, circulation, and light and nutrient regimes in the surface ocean. Such changes in environmental conditions are expected to transform the structure and function of phytoplankton communities. Photosynthetic production by phytoplankton fuels the marine food web and regulates the ocean's capacity to act as a carbon sink. Currently there is a lack of consensus amongst model projections for exactly how climate change will alter phytoplankton community structure, net primary production, and the rate of transport of carbon into the ocean. Model projections are fundamentally limited by the current lack of understanding of the capacity of phytoplankton to both acclimate and to adapt to changes in environmental conditions over a range of different timescales from hours to years. We propose to assess the capacity of phytoplankton to acclimate and adapt to temperature change over different timescales by measuring differences in whole gene expression sequences, growth rate, and physiological traits across diatom strains exposed to different temperatures and temperature regimes over timescales of hours to years. The objective of this work is to I) determine the capacity of phytoplankton to physiologically acclimate and adapt to changes in temperature over different timescales, II) identify genes and physiological mechanisms associated with temperature acclimation and adaptation, and III) determine if there is an energy (photon or carbon) or nutrient (nitrogen or phosphorus) cost associated with temperature acclimation and adaptation. The findings from this work has significant implications for understanding how phytoplankton communities, the marine food web, and the ocean carbon sink are likely to respond to future climate change.*