6843 20240220094509.0 POSTER-2024-0034 Hakim, Kaustubh Exoplanet Ocean Chemistry in the Presence of Diverse Carbonates 2023 2023-07-03 The carbonate-silicate cycle is thought to play a key role in maintaining temperate climates on Earth via continental silicate weathering and seafloor carbonate precipitation. Present-day carbonate pre- cipitation on Earth’s seafloor is mainly attributed to calcium carbonates. However, observations of refractory element ratios in stellar photospheres and planet formation models suggest a large diversity in exoplanet bulk composition and thereby the near-surface composition. In this work, we compute exoplanet ocean pH and carbonate compensation depth (CCD). We find that ocean pH exhibits a limited range of values as a function of ocean temperature and partial pressure of CO2, where the lim- its are given by the absence and presence of carbonates. The CCD increases with ocean temperature and partial pressure of CO2. If the CCD is above the seafloor, the carbonate-silicate cycle ceases to operate and therefore high ocean temperature and partial pressure of CO2 favor the carbonate-silicate cycle. With the help of pure carbonate systems of key divalent elements, we show that magnesium, calcium and iron carbonates produce an increasingly wider parameter space of deep CCDs, suggesting that chemical diversity promotes the carbonate-silicate cycle. This work motivates the inclusion of more chemically diverse targets than Earth twins in the search for life in exoplanets. FED-tWIN STELLA/ FED-tWIN STELLA/ FED-tWIN STELLA NO Complex Planetary Systems II Kavli-IAU Symposium 382, Namur, Belgium kaustubh.hakim@ksb-orb.be CPOSTER