Scientists from Virginia Tech have found evidence that biologically available nitrogen may have played a vital role in the evolution of marine eukaryotes, organisms whose cells have a nucleus. This group of organisms evolved into multicellular creatures and is credited with ushering in a new era for life on Earth, including animals, plants, and fungi. The study, published in Science Advances, sheds new light on the role of nitrogen in this evolution, which had previously been attributed to phosphorus.

Junyao Kang, a doctoral student in the Department of Geosciences, led the study, collaborating with Nanjing University in China. The team used nitrogen isotope analysis of rock samples from the North China Craton, once covered by an ocean and contained rocks dating back 3.8 billion years ago. Kang’s analysis revealed an increase in nitrates around 800 million years ago, coinciding with eukaryotes’ rise.

Kang stated that the data was unique since “nitrogen isotope data are virtually nonexistent from the early Neoproterozoic [era].” The team’s findings were made possible through a collaborative, international approach that connected new data with biological events, particularly the rise of eukaryotes. The study’s authors emphasized the importance of interdisciplinary research and open-access publications in scientific discovery.

The team’s work provides important context about past, present, and future global changes. Shuhai Xiao, professor of geobiology and co-author of the study, stated: “Geologists look at rocks for the same reason that stock traders look at the Dow Jones curve when they make decisions to sell or buy stocks. The geological history written in rocks gives us important context about global changes in the future.” The team hopes to continue researching with NASA on future grants, such as the exobiology program.

References

• Jacques, J. (2023, March 22). Virginia Tech geoscientists shed a light on life’s evolution 800 million years ago. Virginia Tech; Virginia Tech. https://vtx.vt.edu/content/vtx_vt_edu/en/articles/2023/03/flsi-eukaryotic-cells-junayo-kang.html
• Kang, J., Gill, B., Reid, R., Zhang, F., & Xiao, S. (2023). Nitrate limitation in early Neoproterozoic oceans delayed the ecological rise of eukaryotes. Science Advances, 9(12), eade9647. https://doi.org/10.1126/sciadv.ade9647