Pollution in the Marmara Sea is 2 times higher than in the Black Sea
Experts warned that the oxygen-free layer at the bottom of the Marmara Sea is gradually reaching the surface and that failure to prevent the increasing pollution will be a disaster for the Marmara Sea. On the other hand, the extent of the pollution was announced as at least 2 times of the Black Sea.
According to the data of the Middle East Technical University (METU) Institute of Marine Sciences, in the Marmara Sea, while the oxygen value is measured as 8-9 milligrams per litre in the first 30-metre layer where the Black Sea water is found, it drops to 1 to 2 milligrams in the Mediterranean water starting from 30 metres and below 1 milligram in the layer up to 300 metres from the sea floor.
According to the long-term data compiled by the Marmara Sea Integrated Modelling System (MARMOD) Project carried out by METU in cooperation with the Ministry of Environment, Urbanisation and Climate Change for the deep waters of Çınarcık Pit in Eastern Marmara, oxygen values, which were above 2 milligrams per litre in the 1980s, have dropped below 0.5 milligrams per litre today.
According to the long-term data compiled by the Marmara Sea Integrated Modelling System (MARMOD) Project carried out by METU in cooperation with the Ministry of Environment, Urbanisation and Climate Change for the deep waters of Çınarcık Pit in Eastern Marmara, oxygen values, which were above 2 milligrams per litre in the 1980s, have dropped below 0.5 milligrams per litre today.
Prof. Dr. Mustafa Yücel, Deputy Director of METU Institute of Marine Sciences, said that oxygen dissolves in smaller amounts at a certain temperature and salinity level, and that the oxygen especially in the bottom waters has fallen below the threshold values in the last 30-35 years.
Yücel said, “In the last situation, the bottom waters in Eastern Marmara are almost oxygen-free. In recent years, deoxygenation has gradually reached the surface and the oxygen level is below 2 milligrams per litre after 25-30 metres.”
Yücel emphasised that the oxygen level in seawater falling below 2 milligrams per litre means that most of the commercial fish species cannot live in this water and will escape, and noted that oxygen is needed not only by fish but also by zooplankton, which respire and have an important place in the food chain, and their habitats are shrinking.
Yücel, who shared the determination that the habitat areas of the creatures belonging to Marmara or the species using it as a migration route have also narrowed very much, made the following evaluations:
“The reason for the lack of oxygen is first of all pollution. Harmful algae blooms and pollution are intertwined and the lack of oxygen creates more pollution. The end of this path may be rotting organic layers such as mucilage layers that smell bad, where you cannot even see your arm while swimming, where there are colour changes, which may cause infection. The change is still going on and the end of this change is unfortunately the things we have mentioned. The extent of pollution is at least 2 times that of the Black Sea. The system is continuously accumulating it, this accumulation turns inside and supports new algal blooms.”
Pointing out that the decrease in oxygen will cause the formation of hydrogen sulphide, Yücel said, “Hydrogen sulphide first of all means death. This is now the last point of the deterioration of the sea. Bad odour means damage to economic activities in the sea such as fish farms and loss of many services we obtain from the sea. Everything from tourism to aquaculture is affected, it is over.”
