Wrecks at the bottom of the Baltic Sea – a ticking bomb?

Scientists estimate that our sea is a graveyard for thousands of ships – according to the Baltic Marine Environment Protection Commission (HELCOM), there may be as many as 8,000-10,000 of them. At least a hundred of them were considered unsafe due to their fuel or hazardous substance content and closer than 10 nautical miles from the coastline. What are the risks posed by wrecks at the bottom of the Baltic Sea and what can be done to reduce them?

Franken and Stuttgart – particularly dangerous

According to the Naval Hydrographic Office, there are 415 wrecks within Polish territorial waters, of which approx. 100 on the Gulf of Gdansk. Other sources say as many as 3,000. wrecks on the bottom of the Baltic Sea, including aircraft remains and as yet unidentified objects. In the Swinoujscie area, many wrecks were removed after World War II, but in such a way that their fuel tanks remained on the bottom.

The two most dangerous wrecks on the bottom of the Baltic Sea on Polish territory are the Stuttgart and the Franken, sunk in the Gdansk Bay area. The former was a German passenger ship converted into a floating hospital. As a result of the Allied bombing in 1943. standing in the harbor of Stuttgart caught fire, so it was immediately taken to the roadstead and sunk. Its wreck is located two nautical miles from Gdynia Harbor, in a “Natura 2000” area. Minimum since 1999. It is leaking fuel, of which there may have been as much as 300 tons. In 2016. The area of local contamination due to this included 415,000^{square meters}.

April 8, 1945. A few nautical miles east of the Hel Spit, Soviet aircraft sank the German tanker Franken. Measuring almost 180 meters in length, the ship broke into two parts. At the time of the sinking, the Franken’s tanks probably contained about 2,700 tons of carried oil and 300 tons of its own fuel. The exact amount of fuel lying at the bottom is not known, as the tanks are sealed for the time being. According to the MARE Foundation, which works to protect the Baltic Sea and marine ecosystems, up to 0.14 mm of steel is lost from Franken’s hull each year due to corrosion. Given the time that has passed since the end of World War II, the wreck is therefore on the verge of disintegration.

Wrecks at the bottom of the Baltic Sea and the fuel problem

Stuttgart and Franken are not the only potential sources of fuel leakage. The Polish zone also contains large, still unexplored wrecks, among others. Wilhelm Gustloff, Steuben or Goya, as well as dozens of smaller sunken ships and aircraft. Progressive corrosion threatens to collapse the tanks and leak petroleum substances into the sea.

The scale of the environmental catastrophe in the black spill scenario is difficult to estimate. In the vicinity of the Stuttgart wreck, there are already more than 1,000-fold exceedances of some acceptable pollution standards. The lifeless zone around is growing steadily. If fuel leaked from the Franken wreck, among other things, it is expected. years of damage to the marine environment, poisoning a huge number of species and even contaminating beaches in many Baltic countries.

Unfortunately, the process of pumping fuel out of corroding wrecks is expensive and difficult to carry out. A neutron cannon invented in Poland could help realize it. Wreck risk neutralization plans are currently being handled by the Parliamentary Committee on Maritime Affairs and Inland Navigation.

Operation Spectrum, or the fight against microplastics

Wrecks at the bottom of the Baltic Sea also pose other problems. This is because nets and fishing gear, most of which are made of plastic, have sunk along with fishing vessels. They can be a direct threat to fish and mammals that get caught up in their structure, but in addition they are a serious source of microplastic contamination of the sea. When exposed to light, temperature or mechanical action, plastics gradually decompose, resulting in smaller and smaller plastic particles. They penetrate fish and seafood organisms, clouds, tap water, and eventually the lungs and human bloodstream.

Mare Foundation in cooperation with the Maritime University of Technology in Szczecin from 2021. is conducting Operation Spectrum to clean up wrecks at the bottom of the Baltic Sea with nets and synthetic fishing gear. So far, 2,400^{m2 of} entangling nets and 30 kg of bottom trawl from eight wrecks have been fished out. The project will continue in future years.