Growth Responses in the Marine Picocyanobacteria Synechococcus: A Multi Stressor Approach
Abstract: Marine Synechococcus are among the most abundant photosynthetic organisms on Earth, and are often exposed to large fluctuations in temperature and CO2 concentrations. These two key photosynthetic stressors co-vary to different extents in different parts of the ocean, and are expected to change in the coming decades due to ocean acidification and changing circulation patterns. To understand the effects of future global change on marine picocyanobacteria, we cultured the Synechococcus strain WH 8109 (previously isolated from northwestern Atlantic Ocean slope water) under three different temperature (22 °C, 24 °C and 26 °C) and CO2 levels (400 ppm, 600 ppm and 800 ppm) simultaneously. We maintained a constant light intensity of 20 µE m-2 s-1 during the experiments. We also monitored the changes in medium pH during the experimental period. The highest specific growth rate of 0.61 d-1 was observed at 24 °C and 800 ppm CO2 concentration. Also, higher specific growth rates were obtained at 26 °C as compared to 22 °C under the three different CO2 levels tested. Thus, Synechococcus WH8109 showed good growth response at high temperature and CO2 levels, which suggests their potential advantage in the future ocean.
Author: Samarpita Basu
Institution: University of California, Irvine
Location: Irvine, CA, USA