字幕表 動画を再生する 英語字幕をプリント The Titanic was once thought to be indestructible, and we all know how that turned out. And now it's dying a second death on the seafloor as it erodes. It's disappearing so quickly that experts predict that by 2050 there will be no sign of it. Meanwhile, this Greek merchant ship, which sank 2400 years ago, is super well preserved – what the wreck is going on here? Hi, I'm Cameron, and this is MinuteEarth. There are two main factors that determine how long a shipwreck might last on the seafloor. There's a lot to consider, but in general, it comes down to what the ship is made of and how much oxygen there is on the seafloor where it sank. For most of seafaring history, ships – both above and below the water – were made mostly of wood. But during the industrial revolution in the 1840s, people started making ships out of metals – mostly iron and steel – that gave us bigger, stronger ships like the Titanic, the Lusitania, and modern luxury cruise ships. It stands to reason that these big, metal ships should outlast the wooden ones – even underwater – and under some conditions, like, if there is oxygen around, they do. Warm, shallow, oxygen-filled water tends to be full of animals and microbes searching for organic matter to gobble up. A wooden ship that sinks in these waters is a buffet for these decomposers; they'll start breaking down the wreck almost immediately. Shipworms – which are so named for their incredible ability to burrow holes in wooden ships – can completely break down a wooden shipwreck in as little as two years. That's not the case for a metal ship that sinks in shallow waters, because there aren't any critters there capable of digesting iron or steel. Sure, the metal ship will eventually rust, but in these conditions, it will last tens of times longer than the wooden ship. In deeper, colder waters with less oxygen, the rules are reversed. Wooden ships that sink here just… live on. That's because, in the depths, the water has so little oxygen that most organisms – including those wood-chomping decomposers – can't survive. The Black Sea – a particularly oxygen-poor body of water – is home to at least 60 known immaculately preserved ancient shipwrecks from as far back as the time of the ancient Greece; some are in such good shape that archaeologists can literally read the engravings in their planks. Iron ships that sink in similarly cold, deep water aren't so lucky. That's because – although wood-chompers can't survive in these oxygen-poor waters, other, weirder, decomposers can. Instead of using oxygen to make their bodies run, these microbes run on iron. They usually get their iron from geologic vents on the seafloor, but when an iron ship – like the Titanic – reaches their depths, they'll happily feast on it. Scientists estimate that by 2050, these iron-chompers will have consumed the entire Titanic. In other words, my heart may go on, but this ship will be gone. Ok normally I would do a painfully punny segue to our sponsor here. Something like, “you know what ship doesn't get eaten by shipworms or bacteria – a sponsorship!” But instead today I want to give you an update about something amazing that thousands of you have made happen. Just by opening browser tabs, the MinuteEarth community alone has raised more than $20,000 dollars for organizations like Partners in Health, which works to provide community-based health care to those with limited access around the world. This is all through Tab For A Cause, our favorite browser extension that, by adding a couple of ads in the corner of your browser tabs, raises money for charity as you browse the web. But all that tabbing has added up to big bucks – if you're already part of our Tab for a Cause community, let us know in the comments so we can thank you. And if you want to join the MinuteEarth viewers who are literally helping to save lives around the world just by opening tabs, click on the link in the description to get the extension today.
B2 中上級 米 What’s Eating The Titanic?(What’s Eating The Titanic?) 68 3 林宜悉 に公開 2024 年 03 月 22 日 シェア シェア 保存 報告 動画の中の単語