Shipwrecks in the Black Sea

In the Times, William Broad has a long article about the shipwrecks recently discovered by robotic exploration of the Black Sea. I didn't write about this story when it came out because none of the news reports I read had enough information about the project to make me feel comfortable. But Broad has done a great job of putting the discoveries in context.

The story starts with the weird oceanography of the Black Sea. A bunch of big rivers flow into this small sea, flooding it with fresh water and organic matter. The influx of fresh water causes the sea to divide into two distinct zones, with heavier, less saline water in the depths and a 200-meter deep layer of salty water on top. The vast amounts of organic matter mostly sink into the sealed depths. You may have read that when too much fertilizer and so on flows down rivers, a huge dead zone forms around the river mouths, where the excess phosphorus and nitrogen cause bacterial blooms that deplete all the oxygen. This has happened on a grand scale in the Black Sea. As a result the whole sea below about 200 meters is so low in oxygen as to be almost completely dead. In particular, none of the organisms that typically eat wooden shipwrecks are present.

As long ago as the 1970s, underwater explorers realized this and started suggesting that somebody should explore the Black Sea and find the wrecks that might be preserved in the anoxic depths. But they mostly suggested that somebody else do it. The Black Sea is bordered around most of its shores by broad shelves of water less than 200 meters deep – light blue in the map above – so to reach the anoxic bottoms required exploring the deep water in the center, far from land and therefore far from clues as to where wrecks might be found. A sort of needle in a haystack operation.

The folks from the Center for Maritime Archaeology in Southampton, England have raised a huge amount of money from anonymous backers to undertake this search with remotely piloted underwater vehicles. They call this venture the Black Sea Maritime Archaeology Project. Exploring a section of the sea bottom claimed by Bulgaria, they have identified more than 40 shipwrecks, some of them exquisitely preserved. The picture above shows a section of an Ottoman wreck of the 18th century, with intact rope and elaborately carved wooden details.

They have released some amazing images, like this one of the Ottoman ship and the one at the top of the post, which shows what they think is a Venetian vessel of the 13th or 14th century. (Reconstruction of the Venetian ship below.) These images are made digitally using a process called photogrammetry, which

combines photography with the careful measurement of distances between objects, letting a computer turn flat images into renderings that seem three-dimensional.

These vessels are in water more than a mile deep, so exploring them will not be easy. But if rope is preserved, all sorts of other things might be, including documents, clothing, and bones.

The potential here is amazing. But the cost will be astronomical. Fortunately we live in an age of bored billionaires, so raising that money may be more possible in our age than ever before.