Ross Gracey
The importance of diatom biodiversity in the response of ecosystem and biogeochemistry to climate change
Name: Ross Gracey
Primary Supervisor: Prof. Alessandro Tagliabue
Year: 1
Discipline: Ocean Sciences
Presentation type: 3MT slide
Project Title: The importance of diatom biodiversity in the response of ecosystem and biogeochemistry to climate change
Abstract:
“Imaging insights into Southern Ocean Diatom communities and their link to silica availability in the Antarctic Peninsula region”
Understanding community structure is crucial for predicting ecosystem responses to climate change, as current models often neglect phytoplankton diversity and their functional roles. Diatoms are a key phytoplankton group in the Southern Ocean, relying on silicic acid (Si(OH)4) to form their frustules. However, it remains unknown how environmental change impacts community’s structure. Using imaging data from the Tara Ocean’s Mission Microbiome expedition, analysed with EcoTaxa’s machine learning algorithms, we assess phytoplankton communities near the Antarctic Peninsula. Diatoms and Dinophyceae together made up ~64% of the relative biovolume. As expected, diatoms dominated high-silica zones like Antarctic Sound (~80% relative biovolume) but declined to ~13% in lower-silica Weddell Sea stations. Four diatom genera—Corethron, Fragilariopsis, Pseudo-nitzschia, and Odontella—were consistently present. Odontella alone contributed up to 98% relative biovolume in Antarctic Sound. This strong dominance is consistent with previous genomic studies showing high relative abundance of Odontella weissflogii in the same regions.