S1-9 Saturday, Jan. 4 13:30 - 14:00 Responses of Antarctic Microalgae to Seasonal Shifts in Temperature and Salinity YOUNG, JN*; DAWSON, HM; RUNDELL, SM; University of Washington; University of Washington; University of Washington email@example.com https://www.younglab-uw.com/
Microalgae in polar oceans possess a number of physiological adaptations that allow them to thrive under extreme conditions. These include adaptations to low light, cold temperatures and fluctuating salinity. Here, I will show results from two experiments testing how Antarctic microalgae respond to seasonal shifts in temperature and salinity. In the first experiment we use metabolomics to explore how axenic laboratory cultures of the sea-ice diatom, Nitzschia lecointei, respond to a matrix of temperatures (-1C, +4C) and salinities (32, 41). While there was only a small effect on overall growth rates and photophysiology, we observed large shifts in the metabolome, particularly in the regulation of compatible solutes. For the second experiment, natural phytoplankton communities from the Western Antarctica Peninsula are incubated at three different conditions: sea ice (-3C, salinity 50), seawater (0C, salinity 32) and melt (+3C, salinity 20). Here, we saw clear differences in net community production and composition over a 10 day period. We will discuss how seasonal changes in temperature and salinity impacts cellular composition and health and how responses at a cellular level could have far reaching impacts on larger scale polar ecology and biogeochemistry.