Isotopes are versions of an element with slightly different atomic weights than the norm because they have different numbers of neutrons in their nuclei. The researchers were studying ratios of isotopes of lithium. At the same time, the balance of certain variants of molecules in ocean rocks went haywire, Bataille, Liu and their colleagues found. At this point, silica-rich rocks made of countless radiolarian shells disappeared, indicating that the radiolarians may have been snuffed out. A sudden shiftĪll of that may have changed, however, at the end of the Permian and the beginning of the Triassic. Similarly, in the Permian, tiny organisms called radiolarians took up almost all of the silica, thus keeping reverse weathering to a minimum. Silica isn't abundant in today's oceans because tiny planktonic organisms snatch it up to make their shells, so reverse weathering doesn't happen much. During reverse weathering, these clays release more CO2 than carbonate rocks can capture. This happens when the mineral silica is abundant and forms new clays on the ocean floor. When the climate cools, weathering slows and less CO2 is locked up in ocean rocks, thus preventing things from getting too chilly.īut there's another process that can occur in the ocean, called reverse weathering. This creates a feedback loop that keeps global temperatures in check, Bataille said: When it's warmer and weathering is faster, more CO2 flows into the sea and gets locked up in ocean rocks, helping to cool the climate. The warmer the climate, the faster weathering occurs, because chemical reactions happen faster in warmer temperatures and more flowing water means more erosion. There, the calcium combines with carbon dioxide (CO2) to form carbonate rocks. The team wanted to study a process called chemical weathering - when rocks on land break down and release calcium, which erodes into the oceans.
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