Phytoplankton are important producers of volatile organic compounds (VOCs) involved in atmospheric and ecological processes. VOC production can be sensitive to environmental conditions including light intensity and diel changes in photosynthetic metabolism. Not known is the impact of phytoplankton growth rate on VOC production. This study investigated VOC production in two marine phytoplankton species, Dunaliella tertiolecta (green alga) and Thalassiosira weissflogii (diatom), during steady state growth controlled by low (10 µmol photons m -2 s -1 , LL) or high (180 µmol photons m -2 s -1 , HL) light intensity. Oxygen-containing compounds was the most abundant VOC group across both species regardless of light intensity. LL D. tertiolecta produced VOCs including acetone, isoprene, and methanethiol, but VOCs were not detected in HL D. tertiolecta . T. weissflogii produced up to 5.5-fold more VOCs than LL D. tertiolecta , and most of the VOCs produced by T. weissflogii were detected in both LL and HL treatments. Ethanol production in LL and HL T. weissflogii reflected a generalized redox regulatory strategy used in the diatom but not in D. tertiolecta . The contrasting patterns of light-driven growth rate-dependent VOC production in the two species are proposed to reflect their adaptation to distinct light environments, with D. tertiolecta adapted to relatively stable conditions and T. weissflogii adapted to more dynamic light regimes.
Almubarak et al. (Wed,) studied this question.