JAEPRE23 - 30 Evaluating seagrass ecosystems as nature-based solutions against ocean acidification

Habitat forming species of marine macrophytes, such as seagrasses, play a pivotal role in altering the physical and chemical characteristics of their environment and can increase local mean pH by absorbing CO2 from seawater through net photosynthetic activity. Therefore, seagrass meadows have been hypothesized as potential chemical refugia from ocean acidification (OA). However, cycles of photosynthesis and respiration are highly dynamic, and together with multiple biogeochemical and physical processes can induce pH and carbonate chemistry fluctuations that may diminish seagrass capacity to act as refugia for calcifying organisms, but might favor their adaptability. Previous research's limited spatial and temporal scope combined with the intricating underlying drivers of the acid-base equilibria of seawater impedes a comprehensive understanding of seagrass seawater carbonate system controls. The responses of calcifying marine organisms to OA are anticipated to be diverse and complex, raising the questions about how seagrass ecosystems enhance resilience, whether through stress mitigation or increased organisms’ physiological tolerance and adaptation. The overall aim of this proposal is to investigate the role of seagrass ecosystems in conforming the response of calcifying organisms to past, present, and future environmental conditions through a combination of biogeochemical, paleoceanographical, ecological and physiological methods with field and lab approaches.