Beautiful and mysterious, the Black Sea has long attracted sailors, scientists, and marine archeologists. It is one of the youngest seas on the planet and has many fascinating features, one of which is that it is made up of two distinct layers and that the bottom layer is completely devoid of oxygen. However, perhaps the most interesting part lies at the bottom of the Black Sea. A few years ago, while surveying a particular section of the seabed, a team of scientists came across 41 shipwrecks, some of which can be traced as far back as the Byzantine and Ottoman Empire. The sunken ships are so well-preserved that one can see the chisel marks from when the ships were built.

The goal of the expedition was to map and study the floor of the Black Sea, but the international crew of sailors and scientists discovered something they were not expecting.

Jon Adams, the director of the University of Southampton’s Centre for Maritime Archaeology, was the principal investigator on the project. The expedition was part of the Maritime Archaeology Project or MAP. He and his team were mapping the Black Sea floor with sonar technology and ROVs (remotely operated vehicles) to find clues about how ancient humans dealt with rising sea levels. They were aiming for a period from approximately 12,000 years ago as it is presumed that the Black Sea expanded around that time. To their surprise, the ROVs picked up images of around 41 well-preserved shipwrecks. Some of these wrecks are thought to belong to the 19th century, but the oldest ones go as far back as the ninth century.

Despite being at the bottom of the sea for so long, the shipwrecks had not decayed as much as they should have. In fact, some were so perfectly preserved that chisel marks were visible on the wood.

When submerged in seawater, rope and wood are the first things to rot. Most of the shipwrecks that the team found were over 492 feet or 150 meters below the sea level, and some were as deep as 7,217 feet or 2,200 meters at the bottom of the Black Sea. Despite being at such depths for so long, some of the ships were so well preserved that tool and chisel marks were visible on the wood and individual planks. Decorative carvings on the wood, rudders, tills, coils of rope, and rigging materials had evidently survived centuries and they were relatively intact.

It was an incredible find, especially considering that no one had ever discovered something like this. Though historical illustrations and texts could provide enough information about the construction method and appearance of merchant ships belonging to different periods, the MAP team believed that archeologists will be able to verify the historical records independently due to the preserved state of the shipwrecks.

The shipwrecks belong to different time periods. While many of them are thought to be sunken Ottoman ships, while some appear to be from the Byzantine Empire.

Many of the 41 shipwrecks appear to be from a time (presumably the late 800s) when the Byzantine Empire controlled a large portion of the region. Some were Ottoman ships belonging to the 16th and 18th centuries. A medieval Italian vessel and several 19th-century ships were also found. In medieval trade, the Black Sea was regularly used by the Italians. So, the discovery of a Venetian ship, which Marco Polo himself could have recognized, is pretty exciting. The shipwrecks have helped historians to better understand the commercial networks which once linked Europe to the Eastern traders.

Archeologists study and analyze a ship’s anchor, mast, and rigging arrangements, and also clay pot styles in the cargo to determine when the ship was made and where it sailed from. Most of the Black Sea shipwrecks were once merchant ships used for transporting timber, metal, grain, wine, and other commodities. Some of them may have even been Cossack raiding vessels. However, none of the ships show signs of battles, and they are thought to have sunk due to heavy storms. After all, the Black Sea was once nicknamed as the “Hostile Sea” by the Greeks.

It is natural to wonder how these ancient shipwrecks managed to survive for so long. To find the answer, scientists look at how the Black Sea was formed and the unique composition of its waters.

Many marine geologists believe that the Black Sea was merely a freshwater lake some 12,000 years ago when the last Ice Age came to an end. However, as temperatures grew and the ice started to melt, the sea level rose. Water from the Mediterranean Sea began to spill over through the Bosphorus Strait. As a result, the Black Sea was filled up with both freshwater and saltwater, and it created two distinct layers. The upper layer of water is rich in oxygen and low in salt, but the lower level is rich in salt and completely devoid of oxygen. Oxygen levels drop to zero when you reach 150 meters below the surface of the Black Sea. This anoxic layer cannot sustain life, but it is evidently perfect for preserving organic materials such as shipwrecks.

The MAP expedition was conducted by a team of Bulgarian, American, and British scientists. They were able to capture thousands of still photographs and take sedimentary core samples as well.

The MAP team consisted of renowned scientists from Bulgaria, America, and Britain. They spent a month aboard the vessel called the Stril Explorer. The research ship was equipped with powerful and high-tech underwater mapping systems. When studying the seabed using sonar technology, they were able to identify some anomalous shapes. They sent out two remotely operated vehicles, which are worth $7 to $8 million each, to the bottom to take high-res videos, photos, and laser measurements of the objects.

The ROVs were operated and controlled in real-time by researchers aboard the ship, and they worked around the clock to cover as much of the seafloor as they could. The 41 shipwrecks were spread across approximately 2,000 square kilometers. Thousands of still photos were taken from multiple angles, and then a 3D photogrammetry software was used to create a digital model which the scientists could study and manipulate. The team was also able to drill into the seabed and gather sedimentary core samples, which would help to address the original purpose of the mission. A thorough analysis of the core samples should be able to answer some critical questions such as when the Black Sea expanded and how soon the water levels increased.

(Sources: 1, 2, 3, 4)