Increasing concentrations of sulfates allowed bacteria to significantly reduce the share of greenhouse gas in the water of the oceans and the atmosphere. This has led to a cooling and a shift from the "greenhouse" climate to modern glacial regime.
Fluctuations in the concentration of sulfates in the ocean were a major factor in climate change in the past of our planet — the increase in the proportion of these substances led to global cooling and the low content of seawater accompanied warming, according to a paper published in the journal Science.
"When India and Eurasia collided, discovered ancient deposits of salts and their contents fell into the ocean, radically changing the chemical composition of its water. This event led to the "death" of the Eocene — the warmest period of the Cenozoic era of modern, was the cause of the transition from the greenhouse to the modern "glacial" climate "- said one of the authors Adina Paytan of the University of California in Santa Cruz (USA) .
The researchers analyzed the chemical composition of the fluid inclusions in the deposits of sea salt, formed over the last 130 million years. It was found that during this time the concentration of sulfates in the ocean fluctuated strongly enough, several times.
Scientists have tried to understand the reasons for the large fluctuations in the concentration of sulfate, a model of global circulation of sulfur compounds in the atmosphere and ocean.
According to the model, the sharp drop in the concentration of sulphate in the early Cretaceous period was associated with the formation of the South Atlantic Ocean in the Aptian age, approximately 120-110 million years ago. After 70 million years Eurasia faced by India, slowly "drift" from Africa to Asia, from the end of the Cretaceous period, this cataclysm led to the dissolution of a vast sea of gypsum and anhydrite, buried on the coast of Asia from Oman.
The appearance of additional portions of sulphate led to sharp activation of bacteria that feed on methane, a major greenhouse gas. In the Cretaceous and early Cenozoic, these germs are on the "starvation diet" because they lacked the SO4 ions for the active oxidation of methane.
According to scientists, increasing concentrations of sulfates in the middle Eocene allow bacteria to significantly reduce the proportion of greenhouse gases in the water of the oceans and the atmosphere. This has led to a cooling and a shift from the "greenhouse" climate to modern glacial regime.
Based on: RIA Novosti