⇑ Earth 170 million years ago and Earth 105 mya — the Americas and Africa move apart. [Image credit: Colorado Plateau Geosystems, Paleogeography Library]
Global Climate Intrinsically linked to Earth’s Interior
at Million Year Time Scales. These processes can modify ecospace for marine life, driving evolution.
A “cold snap” 116 million years ago triggered a marine ecosystem crisis similar to the ones witnessed in the past as a result of global warming, according to research published in Nature Geoscience.
Analysing the geochemistry and micropaleontology of a marine sediment core taken from the North Atlantic Ocean, the team show that a global temperature drop of up to 5°C resulted in a major shift in the global carbon cycle over a period of 2.5 million years.
Occurring during a time of high tectonic activity that drove the breaking up of the super-continent Pangaea, the research explains how the opening and widening of new ocean basins around Africa, South America and Europe created additional space where large amounts of atmospheric CO2 were fixed by photosynthetic organisms like marine algae. The dead organisms were then buried in the sediments on the sea bed, producing organic, carbon rich shale in these new basins, locking away the carbon that was previously in the atmosphere.
The result of this massive carbon fixing mechanism was a drop in the levels of atmospheric CO2, reducing the greenhouse effect and lowering global temperature.
This period of global cooling came to an end after about 2 million years following the onset of a period of intense volcanic activity in the Indian Ocean. …
The research team highlight in this study how global climate is intrinsically linked to processes taking place in Earth’s interior at million year time scales. These processes can modify ecospace for marine life, driving evolution.
(‘Cold snap’ 116 million years ago triggered marine ecosystem crisis)