Photosynthesis leaves behind a unique calling card, a chemical signature that is spelled out with stable oxygen isotopes, according to a new study in Science. The findings suggest that similar isotopic signatures could exist for many biological processes, including some that are difficult to observe with current tools.
“We’ve found a new type of biosignature,” said co-lead author Laurence Yeung, an assistant professor of Earth science at Rice University. “We show that plants and plankton impart this type of biosignature on the oxygen they produce during photosynthesis. “Yeung, who joined Rice in January, conducted the study with colleagues at the University of California, Los Angeles. Isotopes are versions of an element that differ in their atomic weights. For example, most oxygen atoms contain eight protons and eight neutrons and are represented by the symbol O-16. More than 99.9 percent of Earth’s oxygen is O-16, but two heavier oxygen isotopes exist in trace amounts: O-17, which contains one extra neutron, and O-18, which has two extra.
“Looking at oxygen through the lens of clumped isotopes will give us a lot of new information about how oxygen is made and consumed by plants,” said study co-lead author Jeanine Ash, a graduate student at UCLA. “I’m very excited about what this approach holds for the future.” Read More |
Isotopes of oxygen | There are three stable isotopes of oxygen that lead to oxygen (O) having a standard atomic mass of 15.9994(3) u. Also 10 unstable isotopes have been characterized.
Using stable isotopic analysis, Laurence Yeung, Jeanine Ash, and Edward Young discovered that plants
and plankton impart a unique biosignature on the oxygen they produce during photosynthesis.
Credit: Doug Rumble