CDR Coffee Talk: Rahul Chajwa

Please join us for a CDR coffee talk featuring Rahul Chajwa, Postdoctoral Scholar, Stanford Bioengineering.

Title: Cellular Slingshots and Hidden Comet Tails in the Ocean’s Biological Pump

Abstract: The ocean evokes a sense of mystery and wonder across physics, biology, and chemistry, concealing beneath its sunlit surface a largely unexplored and dynamic world. One of its most awe-inspiring phenomena is the biological pump —a vertical transport process that sequesters ~2–4.5 gigatons of carbon per year from the surface to the deep ocean through a slow shower of sinking aggregates known as marine snow. This flux is initiated by phytoplankton that aggregate and sink through a bath of marine bacteria and viruses, forming the largest sedimenting living suspension on Earth. In this talk, I will explore how non-swimming plankton can inflate dramatically to counteract gravity — what we call cellular slingshots — and how invisible, viscoelastic comet tails in marine snow influence its sinking dynamics. Through this lens, I aim to illuminate the rich physics of soft and biological matter in the ocean, and the microscale dynamics that underpin the global carbon cycle.