Ocean acidification impairs seagrass performance under thermal stress in shallow and deep water

Chiara Ravaglioli, Lucia De Marchi, Serena Anselmi, Emanuela Dattolo, Debora Fontanini, Carlo Pretti, Gabriele Procaccini, Gil Rilov, Monia Renzi, Jacob Silverman, Fabio Bulleri

Research output: Contribution to journalArticlepeer-review


Despite the effects of ocean acidification (OA) on seagrasses have been widely investigated, predictions of seagrass performance under future climates need to consider multiple environmental factors. Here, we performed a mesocosm study to assess the effects of OA on shallow and deep Posidonia oceanica plants. The experiment was run in 2021 and repeated in 2022, a year characterized by a prolonged warm water event, to test how the effects of OA on plants are modulated by thermal stress. The response of P. oceanica to experimental conditions was investigated at different levels of biological organization. Under average seawater temperature, there were no effects of OA in both shallow and deep plants, indicating that P. oceanica is not limited by current inorganic carbon concentration, regardless of light availability. In contrast, under thermal stress, exposure of plants to OA increased lipid peroxidation and decreased photosynthetic performance, with deep plants displaying higher levels of heat stress, as indicated by the over-expression of stress-related genes and the activation of antioxidant systems. In addition, warming reduced plant growth, regardless of seawater CO2 and light levels, suggesting that thermal stress may play a fundamental role in the future development of seagrass meadows. Our results suggest that OA may exacerbate the negative effects of future warming on seagrasses.

Original languageAmerican English
Article number117629
JournalEnvironmental Research
StatePublished - 15 Jan 2024
Externally publishedYes


  • Climate change
  • Light availability
  • Marine plants
  • Ocean acidification
  • Synergistic effects
  • Thermal stress

All Science Journal Classification (ASJC) codes

  • General Environmental Science
  • Biochemistry


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