Possible link between Earth\u2019s rotation rate and oxygenation

J M Klatt,B K Arbic,G J Dick,B A Biddanda,A Chennu

doi:10.1038/s41561-021-00784-3

Abstract

The biotic and abiotic controls on major shifts in atmospheric oxygen and the persistence of low-oxygen periods over a majority of Earth’s history remain under debate. Explanations of Earth’s stepwise pattern of oxygenation have mostly neglected the effect of changing diel illumination dynamics linked to daylength, which has increased through geological time due to Earth’s rotational deceleration caused by tidal friction. Here we used microsensor measurements and dynamic modelling of interfacial solute fluxes in cyanobacterial mats to investigate the effect of changing daylength on Precambrian benthic ecosystems. Simulated increases in daylength across Earth’s historical range boosted the diel benthic oxygen export, even when the gross photosynthetic production remained constant. This fundamental relationship between net productivity and daylength emerges from the interaction of diffusive mass transfer and diel illumination dynamics, and is amplified by metabolic regulation and microbial behaviour. We found that the resultant daylength-driven surplus organic carbon burial could have shaped the increase in atmospheric oxygen that occurred during the Great and Neoproterozoic Oxidation Events. Our suggested mechanism, which links the coinciding increases in daylength and atmospheric oxygen via enhanced net productivity, reveals a possible contribution of planetary mechanics to the evolution of Earth’s biology and geochemistry.

Highlights

The biotic and abiotic controls on major shifts in atmospheric oxygen and the persistence of low-oxygen periods over a majority of Earth’s history remain under debate
Oxygenic photosynthesis (OP) in microbial mats was a substantial source of O2 for the Great Oxidation Event (GOE) ~2.4 billion years ago (Ga), during the stable low-O2 conditions that followed and for the Neoproterozoic Oxygenation Event (NOE) ~600 Ma
Experimental measurements and models of Proterozoic cyanobacterial mat analogues show that longer daylength increases benthic O2 export, changes the balance between aerobic and anaerobic remineralization, and enhances the diel organic carbon (Corg) burial

Summary

Introduction

The biotic and abiotic controls on major shifts in atmospheric oxygen and the persistence of low-oxygen periods over a majority of Earth’s history remain under debate. Experimental measurements and models of Proterozoic cyanobacterial mat analogues show that longer daylength increases benthic O2 export, changes the balance between aerobic and anaerobic remineralization, and enhances the diel organic carbon (Corg) burial.

Results

Conclusion