The results of their research were published in the journal Nature Geoscience.
This period brought intense planetary cooling, which eventually led to glacial movement and a major “Late Ordovician mass extinction.” This mass extinction caused the disappearance of about 85% of the species that lived in the ocean and reshaped the evolution of life on Earth.
Jack Longman, the first author of the research paper, said: “Some people believe that global cooling is driven by the increase in phosphorus entering the ocean. Phosphorus is one of the key elements of life and determines the use of tiny aquatic organisms like algae. The rate at which photosynthesis converts carbon dioxide (CO2) into organic matter.” These organisms will eventually settle to the bottom of the sea and be buried, and ultimately reduce the level of carbon dioxide in the atmosphere and cause cooling.
“The unresolved problem is why glaciers and extinction occurred in two different stages at this time, about 10 million years apart,” said Dr. Tom Gernon, associate professor at the University of Southampton and co-author of the study. “It requires some kind of It is difficult to explain the mechanism to promote the supply of phosphorus.”
The research team found that there were two particularly large pulses of volcanic activity on a global scale, occurring in parts of today’s North America and southern China, which coincided with the two peaks of glacier movement and extinction. “But strong volcanic eruptions are more typically related to the release of large amounts of carbon dioxide, which should promote global warming, so another process must be responsible for the sudden cooling event,” Dr. Gernon explained.
This prompted the research team to consider whether there is a secondary process-the natural decomposition or “weathering” of volcanic material-that may provide the surge in phosphorus needed to explain the glacier phenomenon.
“When volcanic material is deposited in the ocean, it undergoes rapid and profound chemical changes, including the release of phosphorus, which effectively fertilizes the ocean. Therefore, this seems to be a feasible hypothesis, and of course it is also a hypothesis worth testing. “Said Martin Palmer, co-author of the research paper.
Dr. Hayley Manners, Lecturer in Organic Chemistry at the University of Plymouth, said: “This prompted our team to study the volcanic ash layers in younger marine sediments to compare their phosphorus content before and after they interact with seawater and change.” We have this information. , The research team will be able to better understand the potential geochemical impact of the massive volcanic layer produced by the huge volcanic eruption during the Ordovician.
Dr. Benjamin Mills, associate professor at the University of Leeds and co-author of the study, said: “This prompted us to develop a global biogeochemical model to understand the chain reaction of the rapid increase of phosphorus leached from volcanic sediments into the ocean on the carbon cycle.”
The team found that, during the Ordovician period, laid on the seabed wide blanket of volcanic material will release enough phosphorus into the sea in order to promote a series of events – including a wide range of cooling to reduce climate, glaciers, ocean oxygen levels and Mass extinction.
Although it may be very tempting to think that sowing phosphorus into the ocean may help solve the current climate crisis, scientists have warned that fried rice cakes may have more destructive consequences. “Excessive nutrient runoff from sources such as agricultural fertilizers is a major cause of ocean eutrophication-algae grow rapidly, then rot and consume oxygen, which can cause significant damage to the current ecosystem,” Dr. Mills pointed out.
The scientists finally concluded that although large-scale volcanic eruptions can warm the climate through carbon dioxide emissions in a short period of time, they can also promote global cooling on a time scale of several million years. Dr. Longman concluded: “Our research may prompt people to reinvestigate other mass extinctions in the history of the earth.”