They also found variety in the types of building blocks present. Scientists expected to see "amorphous" precursors, minerals that lack a repeating atomic structure. They did—but they also found "crystalline" precursors, minerals that are more structured and orderly. The research is published in the journal Nature Communications. "One fascinating observation is that coral skeletons and mollusk mother-of-pearl form with exactly the same precursors, yet they evolved completely separately from one another," said Pupa Gilbert, a visiting faculty scientist at Berkeley Lab and professor at the University of Wisconsin, Madison. She noted that the two species began making biominerals long after they diverged from one another on the tree of life. "That's cool because it means making a biomineral that way, with so many precursors, is an evolutionary advantage—energetically, thermodynamically, or some other way," Gilbert said. "As a physicist, I find it fascinating that so much of life, and biology in general, is harnessing the beauty of physics to gain evolutionary advantages." Scientists also found different proportions of the building blocks present in different species. The surprise mineral precursor, calcium carbonate hemihydrate (CCHH), and another building block (monohydrocalcite, or MHC) were both found in corals and mollusks. But CCHH and MHC only showed up in trace amounts in sea urchin spines—suggesting that different animals take different approaches to biomineralization. "It is tremendously complicated to run these experiments because we have to analyze the samples right away, while they are fresh, to see the precursors as the biominerals are forming," Gilbert said. "If we wait just one day, we miss these phases that only exist transiently. At Berkeley Lab, we have this unique capability where we can prepare the samples on site and then have access to this fantastic beam and microscopes that are the best in the... |