Kirralee Baker

Abstract Marine diatoms are an abundant and ecologically important phytoplankton group susceptible to changing environmental conditions. Currently available data assessing diatom responses focus on empirical comparisons between present-day and future conditions, rather than exploring the mechanisms driving these responses. Here, we conducted high-resolution growth experiments to map the fitness of diatoms across broad carbonate chemistry landscapes.

References , , , , , , et al. (2017). Delineating environmental control of phytoplankton biomass and phenology in the Southern Ocean. Geophysical Research Letters, 44(10), 5016–5024. https://doi.org/10.1002/2016GL072428 , , , , & (2020). Seasonal modulation of phytoplankton biomass in the Southern Ocean. Nature Communications, 11(1), 5364. https://doi.org/10.1038/s41467-020-19157-2 , , , , & (2021). Southern Ocean in-situ temperature trends over 25 years emerge from interannual variability.

Abstract Diatoms, large bloom-forming marine microorganisms, build frustules out of silicate, which ballasts the cells and aids their export to the deep ocean. This unique physiology forges an important link between the marine silicon and carbon cycles. However, the effect of ocean acidification on the silicification of diatoms is unclear. Here we show that diatom silicification strongly diminishes with increased acidity in a natural Antarctic community.