Evolution of Marine Life Was Influenced by Climate-Shattering Geological Events

As scientists and weather experts continue to be concerned with the major threat of global warming, often associated with higher temperatures than normal that can potentially lead to extreme weather events, researchers quantified how a global cooling event 116-million years ago had severe long-term consequences for marine species.

Researchers based in the UK and Germany show that a link between global cooling and a crash in the marine ecosystem during the mid-Cretaceous greenhouse period could be a cause for concern, even in modern times.

According to this news release from Newcastle University, the research quantifies the amplitude and duration of this global temperature change in Earth's history for the first time.

Findings based on the geochemistry and micropaleontology analysis of a marine sediment core taken from the North Atlantic Ocean indicate a temperature drop of up to 5 degree Celsius. Major geological events initiated a 2.5 million year period of global cooling and later inversed this phenomenon.

The temperature drop was the result of a massive carbon fixing mechanism invoked by tectonic events that created huge new ocean basins around Africa, South America and Europe. The additional space allowed large amounts of atmospheric CO2 to be fixed by photosynthetic organisms like marine algae. Lower levels of atmospheric CO2 gradually choked the greenhouse effect due to this.

The authors highlight that their study shows how the global climate is linked to processes that take place in the earth's interior at million year time scales, and affects the evolution of marine life.

As always it's a question of fine balance and scale," explains Thomas Wagner, Professor of Earth Systems Science at Newcastle University, and one of the leaders of this study.

"All earth system processes are operating all the time and at different temporal and spatial scales; but when something upsets the balance - be it a large scale but long term natural phenomenon or a short and massive change to global greenhouse gases due to anthropogenic activity - there are multiple, potential knock-on effects on the whole system.

"The trick is to identify and quantify the initial drivers and consequences, which remains an ongoing challenge in climate research."