2025 ExoExplorers: Ashika Capirala (Purdue) "Mapping Marine Habitability on Earth-like Exoplanets" скачать в хорошем качестве

2025 ExoExplorers: Ashika Capirala (Purdue) "Mapping Marine Habitability on Earth-like Exoplanets"

Ashika Capirala is part of the 2025 NASA ExoExplorers cohort, a program that aims to enable the professional development of graduate students and/or postdocs in exoplanet research (“ExoExplorers”). The ExoExplorers program, sponsored by NASA’s Exoplanet Exploration Program Office and the ExoPAG Executive Committee, will focus on the professional development of ~10 graduate student and/or postdoc researchers (“ExoExplorers”) at US and international institutions. Each member of the cohort will be featured in a webinar that will be live-streamed to the exoplanet community, helping to increase their visibility within the field and build internal and external research networks. The cohort will also learn from the experiences of established exoplanet researchers and engineers in the field (“ExoGuides”) via a combination of tailored presentations and small group discussions. Title: Using Ocean Dynamics to Map Marine Habitability on Earth-like Exoplanets Abstract: Earth’s oceans have hosted an abundance of biological innovation, and oceans on Earth-like exoplanets may be similar hotspots for life. Habitability for complex, multicellular life requires more than just liquid water, depending additionally on circulation patterns that transport dissolved oxygen (O2) and nutrients within oceans. However, Earth's own ocean circulation has changed through time due to the slowing of Earth's rotation and the rearrangement of continents. Planetary rotation rate affects atmospheric circulation and (in turn) wind-driven ocean circulation, while continental configuration alters surface and deep ocean circulation patterns. Both rotation rate and continental configuration could vary across Earth-like exoplanets, allowing many potential landscapes of circulation and marine habitability. We use a 3D Earth system model to explore these alternate landscapes. We find that slowing rotation enhances ocean circulation and vertical mixing, leading to more efficient nutrient recycling, greater photosynthetic productivity, and higher O2 production. Stronger circulation oxygenates the deep ocean, creating potentially ‘superhabitable’ marine environments, and atmosphere-ocean interactions may also increase O2 biosignature potential on slower-rotating planets. Additionally, we find that changing continents alone can generate highly variable circulation regimes and biogeochemical outcomes. Importantly, for some configurations, the ocean can be highly deoxygenated even under detectable levels of atmospheric O2. We suggest that detecting Earth-like O2, while it may imply the presence of life, does not guarantee complex habitability.