UMaine Scientist Shows How Clays May Have Made Life on Earth Possible
Contact: Larry Mayer (207) 581-3321; David Munson (207) 581-3777
ORONO, Maine – While working on problems facing the clamming industry in mud flats, UMaine oceanographer Larry Mayer began to more fully appreciate the important connection between the preservation of organic matter and the presence of clays. He pursued this connection into the Gulf of Maine, and then into sediments all around the world. Through a recent collaboration with geologists from the University of California Riverside, his discoveries have been put into the context of geological time, and may help to explain how multicellular life on Earth began.
“Ask your average economist what came first — kitty litter or kitties? Likely they’ll reply kitties. In the environment, clays act as a kind of kitty litter. They cover over and seal in organic matter,” said Mayer, pointing out the microscopic interaction between clays and larger organic particles on an electron micrograph in his office. “In the mudflats just beyond the woods here, our data showed that the accumulation of clays enabled the accumulation of organic matter in marine sediments. By burying organic matter, clays made it possible to increase the levels of oxygen in the atmosphere.”
In other words, if you are breathing, you may have clays to thank. From his woodsy office-laboratory tucked away in a corner of UMaine’s Darling Marine Center in Walpole, Mayer explained that the increase in clay deposition that began more than 500 million years ago may have tipped the balance between the production of oxygen by plants through photosynthesis and the consumption of oxygen by single-celled microbes, transforming the earth from a relatively harsh and uninviting place for animals to a fully-oxygenated Eden where multicellular life could flourish.
As part of a research team led by geologist Martin Kennedy of UCR, Mayer helped to collect and analyze samples from critical sites in locales as diverse as Australia, China and Norway. The team’s goal was to test its idea that the earth started making clays in abundance prior to the evolution of animals.
“The layers of sediment act as a tape recorder of Earth’s history,” said Mayer. “The trick was to find the most complete version of that tape. The UCR geologists were able to locate thick successions of rock that could integrate whole continents across big space and time scales. With those data, we were able to show that clays came into the geological record on a world-wide scale between one and one-half billion years ago, during a time period referred to as the late Proterozoic.”
Thus, clays arose just before the earliest proliferation of multicellular animal life – a strange assemblage of Precambrian creatures known as the Ediacarian fauna. As with any scientific enigma, the hows and whys of the Ediacarian explosion depend heavily on the wheres and whens. Mayer and Kennedy believe that the amazing proliferation of multicellular marine life during the Ediacarian was made possible by the holding power of clays.
In other words, you couldn’t get to kitties without first making the kitty litter.
“This research speaks to one of the big questions, if not the biggest question, in geobiology: Why did animal life arise on Earth and what geological conditions make life possible?” said Kennedy. “The natural extension of that question is to ask what needs to happen on other planets for life to exist. It really shows how amazing our planet is and how dependent we are on the incredibly complex series of linkages between geological and biological processes.”
Indeed, much of the research was funded by the National Air and Space Administration. NASA hopes to use the information to better understand the types of conditions that can lead to an environment capable of supporting life on other planets. The information may help NASA researchers as they look at new directions for the nation’s space program.