What ancient shark teeth say about Earth's climate history 🦈

+ NOAA's high-tide flooding report; tracking ocean plastic from space US Edition - Today's top story: Sharks that hunted near Antarctica millions of years ago recorded Earth's climate history in their teeth [View in browser]( US Edition | 14 July 2021 [The Conversation]( Academic rigor, journalistic flair It’s Shark Week – a time to celebrate and learn about these wonderful animals – and here at The Conversation, we’ve marked it in our own way: with really cool science. Sora Kim, a professor of paleoecology at the University of California Merced, shares her research on ancient shark teeth in Antarctica, where sand tiger sharks once roamed. By studying the chemistry of those teeth, she and her colleagues were able to [gain insights into a major climatic change in Earth’s history](. The fossils are “helping solve the mystery of why the Earth, some 50 million years ago, began shifting from a ‘greenhouse’ climate that was warmer than today toward cooler ‘icehouse’ conditions,” she writes. The delta variant of the coronavirus now accounts for more than half of the case in the U.S. and is rapidly spreading in other countries. If a person had been infected by a different variant months ago, will that person have immunity? And how effective are current vaccines? We asked immunologist Jennifer Grier from the University of South Carolina to survey the latest research and answer these questions. Her article is worth a read to understand the details of how immunity works, but her bottom line is simple: [If you’ve already been infected with SARS-CoV-2, the virus that causes COVID-19, you should still get the vaccine to be protected](. When The Conversation U.S. first launched, we were housed at Boston University in a cramped basement room. So when we began thinking about doing stories on the so-called lab leak hypothesis – the notion that the coronavirus escaped from a lab that researches pathogens – a few editors suggested hearing from the people who run BU’s biocontainment lab. Ronald Corley, director of the National Emerging Infectious Diseases Laboratories in Boston, provides [an inside view of how these secure facilities operate and the work they do](. Here are some other science stories from the past week: - [‘Admixture mapping’ genetic analysis yields clues on Alzheimer’s]( - [What you need to know – for now, anyway – on COVID-19 booster shots]( - [How floating wind turbines work]( If there’s a topic or story you’d like our team of science editors to investigate, please reply to this email. Martin La Monica Director of Editorial Projects and Newsletters Sharks’ teeth carry clues about the oceans they swam in. Christina Spence Morgan [Sharks that hunted near Antarctica millions of years ago recorded Earth’s climate history in their teeth]( Sora Kim, University of California, Merced These giant predators are helping solve the mystery of Earth's cooling shift some 50 million years ago. Infection from the coronavirus can produce weaker immunity than vaccination. Wenmei Zhou/ DigitalVision Vectors via Getty Images [Delta variant makes it even more important to get a COVID-19 vaccine, even if you’ve already had the coronavirus]( Jennifer T. Grier, University of South Carolina COVID-19 vaccination produces a more consistent immune response than a past infection. With the delta variant, the difference in protection may be even greater. Security precautions, thoughtful facilities design, careful training and safe lab practices help keep pathogens isolated. Boston University Photography [We work with dangerous pathogens in a downtown Boston biocontainment lab – here’s why you can feel safe about our research]( Ronald Corley, Boston University The microbiologist who directs the National Emerging Infectious Diseases Laboratories at Boston University explains all the biosafety precautions in place that help him feel safer in the lab than out. 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Engineers found a way around the problem. - [What’s a suborbital flight? An aerospace engineer explains]( John M. Horack, The Ohio State University Both Virgin Galactic and Blue Origin are sending spacecrafts – and their billionaire founders – into suborbital flight. But what differentiates a suborbital flight from a trip around Earth? - [Do I need a COVID-19 booster shot? 6 questions answered on how to stay protected]( William Petri, University of Virginia Though currently approved COVID-19 vaccines effectively provide immunity against the virus, it's unclear how long that protection will last. - [Knowing how heat and humidity affect your body can help you stay safe during heat waves]( JohnEric W. Smith, Mississippi State University Which is worse, dry heat or wet heat? 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