Highlights
- Low salinity enhanced the weakening of silicification by ocean acidification (OA).
- OA and salinity influenced the quality of diatom frustules and cell size.
- OA could affect estuarine diatoms’ competitiveness in future environment.
Abstract
Understanding the combined effects of seawater acidification and salinity is crucial for assessing the adaptation of estuarine organisms to climate change. This study examined the physiological and nanostructural responses of two coastal diatoms, Thalassiosira pseudonana and Thalassiosira weissflogii, under different pCO2 and salinity conditions. Our results indicated that high pCO2 and low salinity decreased the biogenic silica and chlorophyll contents in both species. The weakly condensed silicon increased alongside the decrease in biogenic silica under high pCO2 conditions, with this trend being further amplified in low salinity environments. Meanwhile, the biochemical compositions and nanostructure of the diatom frustules were significantly altered by the lower salinity, leading to reduced cell size and porosity. These changes to diatom physiology and morphology may affect the diatoms’ capacity to defend against predators and viruses. This study highlights the chemical and morphological changes occurring in diatom cell walls in future acidic estuarine waters.
Duan W., Zhang Z., Luo M., Xu H., Ou Q., Chen F. & Pan K., 2025. Combined effects of pCO2 and salinity on the silicification of estuarine diatoms. Journal of Experimental Marine Biology and Ecology 582: 152078. doi: 10.1016/j.jembe.2024.152078. Article.
