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  

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