New research in Earth and Planetary Science Letters argues that the breakup of the supercontinent Nuna around 1.46 billion years ago produced vast shallow continental shelves and temperate seas that favored early eukaryotic life. Modeling 1.8 billion years of plate motions and carbon exchange, researchers found reduced volcanic CO2 and enhanced carbon storage improved ocean chemistry. These stable, nutrient-rich margins likely acted as ecological incubators, helping bridge the energy and oxygen gap needed for complex organisms.
Did the Breakup of Supercontinent Nuna Spark Complex Life? New Study Points to Shallow Seas and Lower CO₂
New research in Earth and Planetary Science Letters argues that the breakup of the supercontinent Nuna around 1.46 billion years ago produced vast shallow continental shelves and temperate seas that favored early eukaryotic life. Modeling 1.8 billion years of plate motions and carbon exchange, researchers found reduced volcanic CO2 and enhanced carbon storage improved ocean chemistry. These stable, nutrient-rich margins likely acted as ecological incubators, helping bridge the energy and oxygen gap needed for complex organisms.
09:50 PM, 11/13/2025Science
Rethinking the "Boring Billion": How Nuna’s breakup may have helped life get complex
For decades, the interval from roughly 1.8 billion to 800 million years ago has been dismissed as the "Boring Billion"—a stretch of Earth history thought to show little tectonic, climatic, or evolutionary change. Recent research, however, is challenging that view and showing the period may have been quietly transformative.
A new study published in Earth and Planetary Science Letters and led by Dietmar Müller (University of Sydney) models about 1.8 billion years of plate motions, continental margin evolution, and carbon exchange between the mantle, oceans, and atmosphere. The team focused on the breakup of the supercontinent Nuna, which began fragmenting around 1.46 billion years ago, and how those tectonic changes altered marine habitats and global carbon cycling.
Key findings
The authors find that Nuna’s rifting produced extensive, shallow continental shelves and temperate seas—vast new habitats ideally suited to early complex cells (eukaryotes). At the same time, changes in tectonics reduced volcanic outgassing of CO2 and increased carbon storage in ocean crust, together improving ocean chemistry and stabilizing environmental conditions.
“Our work reveals that deep Earth processes, specifically the breakup of the ancient supercontinent Nuna, set off a chain of events that reduced volcanic carbon dioxide emissions and expanded the shallow marine habitats where early eukaryotes evolved,”
—Dietmar Müller (press statement)
Coauthor Juraj Farkaš (University of Adelaide) emphasizes the ecological role of these margins: “We think these vast continental shelves and shallow seas were crucial ecological incubators. They provided tectonically and geochemically stable marine environments with presumably elevated levels of nutrients and oxygen, which in turn were critical for more complex lifeforms to evolve and diversify on our planet.”
Independent work from the University of Arizona supports this scenario by showing complex organisms demand substantially more energy and oxygen than single-celled protists. Thus, an increase in habitable shallow marine area combined with improved carbon cycling could have provided the environmental and energetic prerequisites for eukaryotic diversification.
Why it matters
Instead of being merely uneventful, the so-called "Boring Billion" may have been a slow but decisive phase during which plate tectonics and carbon cycling prepared global environments for biological complexity. The study underscores how deep-Earth and surface processes interact to shape habitability over geologic time.
Bottom line: The fragmentation of Nuna likely expanded shallow, nutrient-rich marine habitats and reduced volcanic CO2, creating conditions that favored the emergence and diversification of complex eukaryotic life.