Reverse Weathering Is Happening Much Faster Than Scientists Thought and It Could Change How We Understand Climate
For decades, reverse weathering has been one of those quietly important ocean processes that scientists knew mattered but didn’t fully understand. Now, two new studies published in early 2025 are forcing researchers to rethink nearly everything they assumed about how fast this process works, how strongly biology influences it, and how deeply it connects to Earth’s climate system.
These studies, led in part by Dr. Jeffrey Krause, Senior Marine Scientist at the Dauphin Island Sea Lab, reveal that reverse weathering can occur far more rapidly than previously believed and that microorganisms play a major role in driving it. Together, the findings reshape our understanding of ocean chemistry, silicon cycling, and the ocean’s ability to regulate atmospheric carbon dioxide.
What Reverse Weathering Actually Is
Reverse weathering is a geochemical process that happens in marine sediments. Instead of rocks breaking down and releasing elements into the ocean—as happens in traditional weathering on land—reverse weathering does the opposite. Dissolved elements in seawater, including silicon, iron, lithium, and manganese, combine to form new clay minerals directly within seafloor sediments.
This matters because these reactions affect the marine silicon cycle, the chemistry of seawater, and the balance of carbon dioxide between the ocean and the atmosphere. When reverse weathering occurs, it tends to consume alkalinity and release CO₂, meaning it can influence ocean acidity and long-term climate regulation.
Until now, scientists believed reverse weathering was a very slow process, operating mainly over geological timescales spanning thousands to millions of years.
Silicon, Diatoms, and the Ocean Food Web
At the heart of this story is silicon, the second most abundant element in Earth’s crust and a critical nutrient for many marine organisms. One of the most important users of silicon in the ocean are diatoms, microscopic algae that form the foundation of the marine food web.
Diatoms build intricate, glass-like shells made of biogenic silica. When they die, these shells sink to the seafloor, where they were long thought to dissolve slowly or remain relatively unchanged before eventually becoming part of sedimentary rock.
The new research shows that this picture is incomplete—and significantly understates how dynamic these sediments really are.
Study One Shows Clay Minerals Can Form in Just Weeks
The first study, published in Science Advances, focused on determining how quickly biogenic silica can transform into authigenic clay minerals—minerals that form directly within sediments rather than being transported from elsewhere.
To answer this, researchers recreated seafloor conditions in a laboratory, carefully controlling temperature, chemistry, and sediment composition. They used biogenic silica produced by marine diatoms and monitored how it changed over time.
What they discovered was startling. Instead of taking generations, authigenic clay minerals formed in as little as forty days. This rapid transformation was far beyond what most geochemical models had predicted.
The finding alone represents a major shift. It means reverse weathering is not just a slow background process but one that can respond quickly to changes in ocean conditions, potentially influencing climate-related processes on much shorter timescales than previously assumed.
Why Speed Matters for Climate Science
The ocean plays a central role in controlling Earth’s temperature and atmospheric balance, largely by absorbing and storing carbon dioxide. Even small changes in how the ocean processes carbon can have ripple effects on global climate.
Because reverse weathering reactions influence how much CO₂ the ocean retains or releases, the newly discovered rapid pace of these reactions suggests that ocean sediments may regulate carbon more actively and dynamically than scientists realized.
In other words, the seafloor isn’t just a passive storage zone—it may be an active participant in climate regulation.
Study Two Reveals the Powerful Role of Microbes
The second study, published in Communications Earth & Environment, focused on the biological drivers of reverse weathering. Specifically, researchers wanted to understand how microorganisms influence silica cycling in marine sediments.
To do this, scientists used radioactive silicon tracers along with sediment samples collected from two very different environments: the Mississippi River Plume and the Congo Deep Sea Fan. These locations were chosen because they receive large amounts of sediment and nutrients, making them ideal natural laboratories.
The results were striking. Microbial activity increased silica transformation and uptake rates by a factor of three and a half compared to sediments without microbial influence. Within just days, microbes were able to dissolve existing silica and reprecipitate it into new mineral forms.
More than half of the reprecipitated silica in these sediments was driven by microbial processes, while only about a quarter formed through purely abiotic, or nonliving, chemical reactions.
A Major Shift in How Scientists View Microbial Influence
Before this work, most scientists believed microbes influenced silicon cycling mainly in the water column or in extreme environments like hydrothermal vents. These studies clearly show that microbial communities within ordinary marine sediments play a dominant role in reshaping silica and mineral formation.
This fundamentally expands the known reach of microbial influence in Earth systems and suggests that life plays a much larger role in controlling sediment chemistry than previously acknowledged.
What This Means for Climate Models
Taken together, these two studies point to a significant revision in how scientists think about reverse weathering. The process is faster, biologically mediated, and more responsive to environmental change than classic models assumed.
This has direct implications for global carbon cycling, ocean acidity, and long-term climate stability. If marine sediments can adjust carbon and nutrient cycles on relatively short timescales, climate models may need to incorporate these processes more explicitly.
What Comes Next in Reverse Weathering Research
Building on these findings, Dr. Krause is now leading additional projects with collaborators Dr. Panagiotis Michalopoulos and Dr. Brandi Kiel Reese. These efforts aim to uncover the detailed mechanisms behind microbially mediated reverse weathering, including how specific microbes interact with minerals and influence chemical reactions.
The broader goal is to better understand how life shapes mineral formation, nutrient availability, and the ocean’s long-term ability to regulate atmospheric carbon dioxide.
Why This Research Matters Beyond the Ocean Floor
Reverse weathering may happen out of sight, but its effects extend far beyond marine sediments. By reshaping how silicon, carbon, and trace metals move through the ocean, this process influences everything from marine ecosystems to global climate trends.
These studies remind us that some of the most important climate-related processes are still being discovered—and that even the quiet chemistry of the seafloor can have global consequences.
Research papers referenced:
https://www.science.org/doi/10.1126/sciadv.adt3374
https://www.nature.com/articles/s43247-025-02941-7
