美国弗吉尼亚理工大学Shuhai Xiao的课题组发现，新元古代早期海洋中硝酸盐的限制，延缓了真核生物的生态崛起。相关论文发表在2023年出版的《科学进展》杂志上。

为了评估硝酸盐有效性是否在这一进化事件中发挥了重要作用，该课题组测定了华北淮北群拉伸纪早期(约ca. 1000Ma-ca. 800Ma)海相碳酸盐的氮同位素组成(δ¹⁵N)。这些数据填补了δ¹⁵N记录的一个关键空白，并表明了新元古代早期海洋中硝酸盐的限制。元古代沉积δ¹⁵N数据的汇编显示，δ¹⁵N值在约800 Ma时逐步增加。

盒模型模拟表明，这种逐步增加可能代表海洋硝酸盐有效性增加了约50%。新元古代早期海洋中有限的硝酸盐的供应，可能推迟了真核生物的生态崛起，直到约800 Ma时，此时硝酸盐供应的增加，加上其他环境和生态因素，可能促进了海洋生态系统从原核生物主导向真核生物主导的转变。

据介绍，新元古代早期(大约在ca. 800 Ma)见证了古代真核生物的初步生态崛起。

附：英文原文

Title: Nitrate limitation in early Neoproterozoic oceans delayed the ecological rise of eukaryotes

Author: Junyao Kang, Benjamin Gill, Rachel Reid, Feifei Zhang, Shuhai Xiao

Issue&Volume: 2023-03

Abstract: The early Neoproterozoic Era witnessed the initial ecological rise of eukaryotes at ca. 800 Ma. To assess whether nitrate availability played an important role in this evolutionary event, we measured nitrogen isotope compositions (δ¹⁵N) of marine carbonates from the early Tonian (ca. 1000 Ma to ca. 800 Ma) Huaibei Group in North China. The data reported here fill a critical gap in the δ¹⁵N record and indicate nitrate limitation in early Neoproterozoic oceans. A compilation of Proterozoic sedimentary δ¹⁵N data reveals a stepwise increase in δ¹⁵N values at ~800 Ma. Box model simulations indicate that this stepwise increase likely represents a ~50% increase in marine nitrate availability. Limited nitrate availability in early Neoproterozoic oceans may have delayed the ecological rise of eukaryotes until ~800 Ma when increased nitrate supply, together with other environmental and ecological factors, may have contributed to the transition from prokaryote-dominant to eukaryote-dominant marine ecosystems.

DOI: ade9647

Source: https://www.science.org/doi/10.1126/sciadv.ade9647