Effects of CO2 on the Nitrogen Isotopic Composition of Marine Diazotrophic Cyanobacteria,Geophysical Research Letters

当前位置： X-MOL 学术 › Geophys. Res. Lett. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Effects of CO2 on the Nitrogen Isotopic Composition of Marine Diazotrophic Cyanobacteria
Geophysical Research Letters ( IF 4.6 ) Pub Date : 2024-10-03 , DOI: 10.1029/2024gl110599
Zuozhu Wen, Ruotong Jiang, Tianli He, Thomas J. Browning, Haizheng Hong, Shuh-Ji Kao, Jin-Yu Terence Yang, Dalin Shi

Biological N₂ fixation has been crucial for sustaining early life on Earth. Very negative δ¹⁵N values detected in Archean sediments, which are not observed in present-day environments, have been attributed to the low efficiency of proto-nitrogenases. Alternatively, variations in early atmospheric CO₂ may also play a role. Here we examine the effects of CO₂ concentrations on the biomass δ¹⁵N signatures of the diazotrophs Trichodesmium erythraeum and Crocosphaera watsonii, which utilize Mo-Fe nitrogenase (the most common form of the enzyme). Our results show that these organisms produce biomass with δ¹⁵N values up to ∼3‰ lower under both decreased and elevated CO₂ concentrations compared to modern levels (∼380 μatm). These deviations from modern CO₂ levels reduce nitrogenase enzyme efficiency, leading to increased organismal isotopic fractionation during N₂ fixation. This study offers an alternative explanation for the observed fluctuations in geological δ¹⁵N records and provides new insights into the past nitrogen cycle on Earth.

更新日期：2024-10-04

点击分享查看原文

点击收藏

公开下载

阅读更多本刊新发论文本刊介绍/投稿指南