Ecological changes following intense volcanic activity 230 million years ago paved the way for dinosaurs to become the dominant species on Earth. Photo by ELG21
Sept. 27 (UPI) -- A few hundred million years before an asteroid wiped the dinosaurs out, a series of volcanic eruptions accelerated their rise to power.
According to a new study, published Monday in the journal PNAS, a series of volcanic eruptions, beginning 230 million years ago, dramatically altered Earth's carbon cycle and climate patterns, resulting in significant ecological and environmental changes.
When scientists analyzed detailed sediment and fossil plant records from a lake in North China, they found strong links between pulses of intense volcanism and major climatic shifts, including marked increases in temperature and humidity.
These dramatic changes reshaped the planet's biodiversity: large numbers of marine species disappeared, conifers proliferated and dinosaurs cemented their place atop the global food chain.
"Within the space of two million years the world's animal and plant life underwent major changes including selective extinctions in the marine realm and diversification of plant and animal groups on land," study co-author Jason Hilton said in a press release.
"These events coincide with a remarkable interval of intense rainfall known as the Carnian Pluvial Episode," a professor of paleobotany and paleoenvironments at the University of Birmingham in Britain.
Researchers were able to divide the 2-million-year-long shift into four distinct episodes, each driven by a volcanic pulse. These pulses resulted in larger amounts of carbon being released into the atmosphere, warming the planet and triggering intense periods of rain.
Geologic data from Central Europe, East Greenland, Morocco, North America and Argentina suggest drainage basins expanded across the globe during this time period, with swamps and lakes swelling across the planet's continental interiors.
The timing of the climatic shifts suggest dinosaurs were uniquely equipped to take advantage of the ecological changes, though researchers aren't yet certain why.
"This relatively long period of volcanic activity and environmental change would have had considerable consequences for animals on land," said Emma Dunne, a paleobiologist at the University of Birmingham who was not involved in the study.
"At this time, the dinosaurs had just begun to diversify, and it's likely that without this event, they would never have reached their ecological dominance we see over the next 150 million years," said Dune.