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A team of researchers from the U.K., China, and Italy has found evidence that suggests oxygen depletion in the world's oceans led to the end-Triassic mass extinction. In their paper published in the journal Science Advances, the group describes their study of ancient rocks found in multiple locations around the world.

Human beings are naturally creative tool users. When we need to drive in a nail but don't have a hammer, we easily realize that we can use a heavy, flat object like a rock in its place. When our table is shaky, we quickly find that we can put a stack of paper under the table leg to stabilize it. But while these actions seem so natural to us, they are believed to be a hallmark of great intelligence-only a few other species use objects in novel ways to solve their problems, and none can do so as flexibly as people. What provides us with these powerful capabilities for using objects in this way?

Silicon is the second-most abundant element in Earth's crust and it plays a vital role in plant life, both on land and in the sea. Silicon is used by plants in tissue building, which helps to ward off herbivorous animals. In the ocean, phytoplankton consume enormous amounts of silicon; they get a constant supply courtesy of rivers and streams. And silicon winds up in rivers and streams due to erosion of silicon-containing rocks. Land plants also use silicon. They get it from the soil. In this new effort, the researchers began by noting that the terrestrial biogeochemical cycling of silicon (how it moves from plants back to the soil and then into plants again) is poorly understood. To gain a better understanding of how it works, they ventured to a part of Western Australia that, unlike other parts of the world, has not been impacted by Pleistocene glaciations. The soil there gave the researchers a look at the silicon cycle going back 2 million years.