The history of life on Earth illustrates that perturbations on a scale of 10s-100s of kyr – e.g., a single large extraterrestrial impact or large-scale volcanic event – greatly affect the viability of global ecosystems (e.g., mass extinctions). Thus, planetary habitability is not constant. Instead, it varies temporally on 10s of kyr to Myr scale due to internal (e.g., volcanism, plate tectonics) and external (e.g., Milankovitch cycles, asteroid/cometary impacts) perturbations. Typically, exoplanetary studies have focused on analyzing long-term planetary habitability for exoplanets considering long term changes (10s of Myr to Byr) in stellar insolation, volcanism, and weathering using coupled planetary surface-interior evolution models. However, no work has yet sought to quantify the carbon cycle effects of the shorter term solid Earth perturbations on planetary habitability. In this talk, I will discuss some of our ongoing work to address this gap by analyzing the dynamics of the ocean carbon cycle since it controls the rate of ecosystem recovery on short-medium timescales. I will show results focused on two primary features: (a) the role of solid Earth boundary conditions, especially global ocean bathymetry on the climate dynamics and ocean chemistry and (b) the effect of large volcanism on surface climate and habitability. Although these results primarily focus on present-day Earth-like conditions, they provide us process-based understanding of these perturbations and help us towards identifying the characteristics of potentially habitable environments in the Solar System and beyond.

Speaker: Tushar Mittal (Penn State)

Talks are held in the STScI John N. Bahcall Auditorium. Light lunch (provided) starts at 12pm; talk starts at 12:30pm.

Planets, Life, and the Universe Lecture Series presentations are also webcast live. Webcasts can be viewed at the STScI webcast site during the scheduled presentation, and can be found afterward in the STScI webcast archive.

STScI is located in the Muller Building on the Johns Hopkins University Homewood campus. View a JHU map and directions.