Deep-Sea Lava Rubble Holds Key to Long-Term Carbon Storage, Scientists Discover
A groundbreaking study reveals that accumulations of broken lava beneath the ocean surface act as significant, previously unrecognized reservoirs for carbon dioxide, offering new insights into Earth’s long-term carbon cycle. The research, stemming from analysis of rock samples dating back approximately 60 million years, demonstrates how CO2 becomes trapped within these formations, potentially mitigating atmospheric levels over vast timescales.
The findings, published following Expedition 390/393 of the International Ocean Discovery Program, could reshape our understanding of how the planet naturally manages carbon.
Unlocking the Secrets of the Deep Ocean Floor
Researchers drilled deep into the seafloor of the South Atlantic Ocean, recovering core samples of lava rubble – known as breccia – to measure the amount of CO2 incorporated into the rock. This material forms as underwater mountains erode, creating vast deposits of broken lava.
“We’ve known for a long time that erosion on the slopes of underwater mountains produces large volumes of volcanic rubble, much like scree slopes on continental mountains,” explained a lead researcher from the University of Southampton. “However, our drilling efforts recovered the first cores of this material after it has spent tens of millions of years being rafted across the seafloor as Earth’s tectonic plates spread apart.”
The analysis revealed a surprising capacity for carbon storage. These porous and permeable deposits, the researchers found, are gradually cemented by calcium carbonate minerals formed from seawater, effectively locking away CO2.
How Earth’s Carbon Cycle Works
The amount of carbon dioxide in the atmosphere isn’t static; it’s influenced by a slow, continuous exchange of carbon between Earth’s interior, the oceans, and the atmosphere over millions of years. Understanding this long-term carbon cycle is crucial for predicting future climate scenarios.
As a researcher noted, “The oceans are paved with volcanic rocks that form at mid-ocean ridges, as the tectonic plates move apart creating new ocean crust. This volcanic activity releases CO2 from deep inside the Earth into the ocean and atmosphere.” However, the ocean isn’t simply a passive container. Seawater interacts with the cooling lava, triggering chemical reactions that remove CO2 from the water and store it within the rock as minerals.
A “Sponge” for Carbon: Breccia’s Unexpected Role
The team’s research quantified the extent of this CO2 incorporation into ocean crust. The results were striking: the lava rubble contained between two and 40 times more CO2 than previously sampled lavas.
“This study revealed the importance of such breccia, which forms due to the erosion of seafloor mountains along mid-ocean ridges, as a sponge for carbon in the long-term carbon cycle,” a senior researcher stated. This discovery marks the first time the significant role of these formations as extensive carbon-holding structures has been clearly recognized.
The findings offer a vital piece of the puzzle in understanding Earth’s natural carbon regulation mechanisms, and highlight the importance of continued deep-sea exploration for uncovering hidden geological processes that impact our planet’s climate.
