Meta-Omics Analysis Reveals Global Distribution of Toxic Pseudo-nitzschia and Enhanced Neurotoxin Production Under Climate Warming.

The harmful diatom Pseudo-nitzschia produces the neurotoxin domoic acid (DA), threatening human health and seafood safety in a changing climate. However, global patterns of Pseudo-nitzschia abundance and the responses of DA production to underlying environmental drivers remain poorly understood, hindering accurate projections of their responses to environmental change. Using global meta-omics data from Tara Oceans, alongside field survey data from the Chinese coasts and the Southern Ocean, we present the first evidence that four of the most toxic species-Pseudo-nitzschia multiseries, Pseudo-nitzschia multistriata, Pseudo-nitzschia delicatissima, and Pseudo-nitzschia pungens-are prevalent not only in coastal ecosystems but also in open ocean environments, spanning from pole to pole. We identify rising temperatures are recognized as a key driver of Pseudo-nitzschia's spatial distribution, DA production, and biosynthetic metabolism. Global models suggest that by 2100, under the SSP2-4.5 climate scenario, the abundance of P. multiseries will increase by approximately 75.4%, while toxin production will be even more significantly enhanced, rising by up to 200.4%. This study significantly expands the known global distribution of these neurotoxin-producing diatoms and predicts their increasing prevalence and toxicity under future global changes.