In a world first, UCD scientists are unlocking the secrets of prehistoric mass extinction, writes Anthony King
Fancy a walk through the climate that existed during the Jurassic period 200 million years ago? Scientists at University College Dublin are now able to do just that using six walk-in chambers that will recreate environmental conditions from the past.
The university has installed six of these large chambers, each with a footprint of about four square metres. The object is to duplicate past conditions to better understand how plants respond to changing climatic conditions, explains Dr Matthew Haworth, a researcher at UCD's School of Biology and Environmental Science.
The chambers will allow scientists simulate prehistoric atmospheres and subject plants to conditions they have not experienced for millions of years.
The facility is unique worldwide because it can adjust the quantities of three different atmospheric gases - carbon dioxide, sulphur dioxide and oxygen. Light intensity, humidity and weather conditions will also be regulated.
Initial experiments are looking at the Triassic-Jurassic boundary 200 million years ago, which marks one of the five great extinction events in Earth's history, Dr Harworth explains.
"We will change the atmosphere and see how plants respond. We will then relate that back to what occurred in the fossil record, and so create a more accurate picture of what happened at the Triassic-Jurassic boundary."
Some 90 per cent of species in North America and Europe became locally or regionally extinct at this time, but no one knows what caused them to die off: among the suspects are meteorite impacts, methane released from oceans, volcanism, sea-level change and global warming. The growth chambers should help scientists solve the mystery.
Dr Haworth views massive volcanism as the most likely culprit. The extinction coincided with one of the greatest eras of volcanic activity, with hundreds of cubic kilometres of basalt lava released over large parts of the Earth's surface. The volcanoes also spewed plumes of toxic gas that fumigated the entire planet.
The growth-chamber experiments will test the effect of one of these noxious gases - sulphur dioxide - on the plants inside. For safety reasons, levels far below those of the Triassic will be used, though researchers will still be restricted to just four hours in the chambers per day for safety reasons.
Plants respond to just 20 parts of sulphur dioxide per billion and those in the chambers will experience one hundred times that amount. Sulphur dioxide is known to affect the breathing pores and the protective layer on the leaf surface.
The end of the Triassic also saw a massive rise in carbon dioxide concentrations and global warming, possibly due to volcanism. The experiments will have relevance to climate change today.
UCD's Dr Claire Belcher is using the growth chambers to investigate oxygen levels, given suggestions that low oxygen could be implicated in animal and plant extinctions. Her method is a pyromaniac's dream. "I'm igniting various things - starting with matches, paper and resinous pine wood - in the chambers at a range of oxygen concentrations," she says.
The plants that will face these environmental challenges are all "living fossils". Many are rare and had to be brought in from as far away as Japan, New Zealand, Australia and China. They include wollemi pine, royal fern, gingko, swamp cypress and cycads such as Lepidozamia.
"We are growing them in preparation to subjecting them to all these horrible atmospheric conditions and we hope we don't kill them," says Dr Jennifer McElwain, the group's leader.
But if the toxic gases or low oxygen doesn't get them, the rain might. "We can change the humidity or mist the vegetation," says Dr Haworth. "Once we start misting the chambers and pumping in sulphur dioxide, we can create our own acid mist or rain."