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If you want to understand an ecosystem, look at what the species within it eat. In studying food webs-how animals and plants in a community are connected through their dietary preferences-ecologists can piece together how energy flows through an ecosystem and how stable it is to climate change and other disturbances. Studying ancient food webs can help scientists reconstruct communities of species, many long extinct, and even use those insights to figure out how modern-day communities might change in the future. There's just one problem: only some species left enough of a trace for scientists to find eons later, leaving large gaps in the fossil record-and researchers' ability to piece together the food webs from the past.

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.

The researchers investigated food consumption of the Huaca Prieta and Paredones peoples, two neighboring groups who lived less than half a mile apart. Participating were Tiffiny Tung, associate professor of anthropology, Larisa DeSantis, associate professor of biological sciences and earth and environmental sciences and Tom Dillehay, senior research professor and University Distinguished Professor of anthropology and religion and culture emeritus and Rebeca Webb Wilson University Chair Emeritus.

"With each interaction, Alexa is training to hear better, to interpret more precisely, to trigger actions that map to the user's commands more accurately, and to build a more complete model of their preferences, habits and desires. What is required to make this possible? Put simply: each small moment of convenience - be it answering a question, turning on a light, or playing a song - requires a vast planetary network, fueled by the extraction of non-renewable materials, labor, and data. The scale of resources required is many magnitudes greater than the energy and labor it would take a human to operate a household appliance or flick a switch. A full accounting for these costs is almost impossible, but it is increasingly important that we grasp the scale and scope if we are to understand and govern the technical infrastructures that thread through our lives. III The Salar, the world's largest flat surface, is located in southwest Bolivia at an altitude of 3,656 meters above sea level. It is a high plateau, covered by a few meters of salt crust which are exceptionally rich in lithium, containing 50% to 70% of the world's lithium reserves. 4 The Salar, alongside the neighboring Atacama regions in Chile and Argentina, are major sites for lithium extraction. This soft, silvery metal is currently used to power mobile connected devices, as a crucial material used for the production of lithium-Ion batteries. It is known as 'grey gold.' Smartphone batteries, for example, usually have less than eight grams of this material. 5 Each Tesla car needs approximately seven kilograms of lithium for its battery pack. 6 All these batteries have a limited lifespan, and once consumed they are thrown away as waste. Amazon reminds users that they cannot open up and repair their Echo, because this will void the warranty. The Amazon Echo is wall-powered, and also has a mobile battery base. This also has a limited lifespan and then must be thrown away as waste. According to the Ay