[M-IS07] Astrobiology

[MIS07-P08] Modeling the Light Environment in the Archean Oceans

*Chihiro Arai¹, Taro Matsuo¹, Kumiko Ito-Miwa¹, Yuri I. Fujii², Shinnosuke Takeda², Satomi Kanno¹ (1.Nagoya University, 2.Kyoto University)

Approximately 2.5 billion years ago into the Archean Era, the Earth was critically transitioning from a reducing to an oxidizing environment with the advent of oxygenic photosynthetic organisms (i.e., cyanobacteria). This global-scale oxidation of the Earth is believed to have promoted the development of the ozone layer and the prosperity of aerobic respiration, leading to the development of diverse ecosystems. On the other hand, the gradual oxidation of the surface environment before the Great Oxidation Event (GOE) might have significantly altered the light environment under water due to the deposition of Fe(III) hydroxide caused by the oxidation of dissolved ferrous iron, Fe(II), at that time. This research involved simulating underwater light transmission in the Archean oceans, considering the attenuation of light due to Fe(III) hydroxide present in the oceans. Our results provide insights into the habitability of the Earth's surface in the Archean era and contribute to the framework for understanding the co-evolution of photosynthetic organisms and their light environments. Our poster presents an overview of the transmission spectrum underwater in the Archean era and discusses its potential impact on the evolution of life.