About three-quarters of Earth's surface is covered with water. These waters are home to millions of living species and make a great contribution to biodiversity.
In addition to making a great contribution to climate-friendly clean energy production, they also provide us with 16% of all animal protein used in the world through fish.
Likewise, the oceans and seas are an effective sink for carbon dioxide, one of the important greenhouse gases that cause global warming. Therefore, the seas and oceans function as a kind of life support unit for living beings.
The world's seas and oceans are also affected by the problems caused by human activities that try to predominate nature instead of being a part of it.
According to the World Meteorological Organization's (WMO) 2020 Global Climate Outlook Report, effects such as record-breaking temperatures in recent years and carbon dioxide concentration, which increased by 50% compared to the preindustrial period, also increase acidification in the seas.
Besides, another danger that awaits the waters is pollution. According to the 2021 edition of the United Nations World Water Development Report (UN WWDR 2021), 80% of the wastewater generated on a global basis is discharged into water resources without treatment.
Most of the untreated domestic and industrial wastewater, which is released into waterways such as streams and rivers, eventually reaches the seas. The organic and chemical waste loads they carry pose a serious threat to the seas.
Turkey, which is surrounded by seas on three sides, is also suffering from such problems. With the algae explosions, the number of which has increased rapidly in recent years, the current problem is "sea snot," or mucilage.
Turkey's seas in its "Blue Homeland" also contain innumerable living species. One of these living groups is the phytoplankton.
Phytoplankton are at the bottom of the food pyramid of submarine life. Like plants on land, they are autotrophic creatures that produce their own food by photosynthesis utilizing solar energy and give oxygen to the environment.
Therefore, phytoplankton can be referred to as the trees of underwater life. According to scientists, these organisms are responsible for almost half of the world's oxygen production.
Just as the excess of everything is harmful, the overgrowth of phytoplankton also creates some problems. The algal blooms seen in the Marmara Sea, especially the Golden Horn, in recent months are one of these events.
Another problem is mucilage, which is perhaps one of the biggest environmental disasters in recent Turkish history. Of course, some environmental factors must have contributed to this situation.
The main factors are temperature and nutrient availability. If there is light, warmth and food, it means there is a suitable environment for reproduction.
The nutrient used in overgrowth is essentially nitrogen and phosphorus-containing pollution. When there is more food in the environment, more plankton is needed to consume it. Hence, overgrowth occurs. When the food runs out, the phytoplankton die. The phenomenon called algae explosion is exactly this in a simple sense.
In mucilage, the situation is somewhat different. Mucilage is a secretion produced by phytoplankton in response to stress in the environment as a result of overgrowth. The process can be called natural, while what is unnatural is the dense formation.
The stagnation in the waters and the extinction of an intermediate species that feed on phytoplankton in the lowest layer of the food chain, unable to adapt to the new conditions caused by overfishing or global climate change, will disrupt the continuity in the food chain, and this may also have affected overgrowth.
Mucilage is the mucus secreted by almost all plants, so it is harmless. However, they do offer a suitable breeding ground for pathogens. This structure is formed when other living things such as bacteria and viruses multiply in these areas.
They rise to the surface as a result of the low density of the dead ones due to air bubbles entering them. By forming a layer on the sea's surface, they prevent both sight, smell and light penetration into the sea and pose a risk to living creatures.
Again, mucilage, the density of which increases as a result of the trapping of heavy metals or suspended solids in the sea, causes a lot of harm to marine life, such as sinking to the bottom and covering the seagrass and creatures that live in the seagrass, such as mussel and oyster, causing them to die over time.
This sticky and contagious secretion also harms fish larvae. Therefore, it affects the food supply chains by causing a decrease in fishing activities.
The dead layer on the surface is usually dragged to the coast by wind and wave action, preventing tourism activities by restricting the use of beaches. Likewise, the formations that continue both on the surface and in the sea can also disrupt ship transportation.
In this respect, it should be considered not only in terms of the environment but also as a problem affecting development.
It is possible to talk about the existence of mucilage at every point where the conditions we mentioned are evident.
Mucilage can occur in any environment where conditions are suitable. Factors such as the location and geological structure of the Marmara leave the sea open to such risks.
One of the reasons is that the Marmara Sea essentially constitutes a transition corridor between the Mediterranean and the Black Sea.
Due to the different salinity rates of the Mediterranean and Black Sea, the significant difference between their densities creates a two-layered current in the Marmara.
While there is low-density Black Sea water in the upper layer, there is high-density Mediterranean water in the lower layer.
While the temperature of the seawater is expected to decrease with depth, the Mediterranean water, which forms the undercurrent of the Marmara, is relatively warmer and the temperature remains almost constant in this region.
The two-layer structure limits vertical mixing. On the surface, the circulation that occurs near the shores of Tekirdağ in the northwest, where the deep pits of the Marmara are located, is very rare, especially in the Gulf regions. This situation creates stagnation in Marmara.
Another factor that leads to the formation of mucilage is temperature. The temperatures in the Turkish seas, which are located in the Mediterranean basin and are among the places most affected by climate change, seem to have increased by 1-2 degrees Celsius (1.8-3.6 degrees Fahrenheit), according to the data.
This value has exceeded 2 degrees Celsius in Marmara. Again, the pollution resulting from the accumulation of many years causes serious turbidity in the Marmara. This turbidity allows more heat to be trapped here, causing the ambient temperature to rise even higher than in other seas.
The last and most important factor is pollution. In this respect, the Marmara Sea is under a great deal of pressure compared to other seas.
In addition to a population of 25 million living in seven provinces located on its approximately 1,000-kilometer (621-mile) long coasts; the Marmara, which hosts more than 50% of the country's industry and where animal husbandry and agricultural activities are intense, is under great pressure in this context.
Likewise, due to its being a transit corridor, it also hosts very large ship mobility. The Marmara region is an industry-intensive region.
For years, the wastewater generated since the 1970s has been discharged into water resources without any treatment.
Over time, this pollution led to an accumulation. Although especially after 1994, when President Recep Tayyip Erdoğan took over the helm in the Istanbul municipality, environmental investments increased but with the increase in pressure elements, pollutants continued to suffocate the Marmara.
In addition, the pollution carried by the rivers coming from Europe and Russia, such as the Danube, Dnieper, Rioni, Dniester, pouring into the Black Sea, also comes to the Marmara with the surface currents and adversely affects the region.
Along with 43,000 giant transit ships annually, urban sea lines connecting the continents, the coasts, and the urban ferry lines and fishing boats, the number of which exceeds thousands, also create shipping-related pressure on the Marmara. Wastewater generated as a result of domestic and industrial activities is the main source.
Likewise, due to the pandemic, it is highly likely that high amounts of phosphorus-rich detergent waters triggered this situation.
Another triggering factor can be considered as the heavy rains that have affected the Thrace region in recent months, carrying the heavy load of surface pollution, especially agricultural fertilizers, to the Marmara.
If any of the factors that led to the formation of the mucilage disappear, the problem will be resolved over time. The only controllable factor is pollution, in other words, nutrient flow.
According to the evaluations of the Union of Municipalities of Marmara, 53% of the wastewater generated in the region is only pretreated and discharged to the sea.
There are no units to remove pollutants such as carbon, nitrogen and phosphorus that cause problems in wastewater.
These facilities urgently need to be converted to advanced biological treatment and existing facilities need to be actively operated. We also need to reduce the waste load from surface areas.
In this context, it is necessary to be more conscious of the use of fertilizers to reduce the nitrogen and phosphorus-based inputs into the sea resulting from agricultural activities.
The Turkish state under the leadership of Erdoğan has followed the issue from the first day. The Ministry of Environment and Urbanization has actively participated in field studies.
With the contribution of hundreds of scientists, the ministry developed and started to implement the Marmara Sea Protection Action Plan, which includes 22 items such as control, inspection and monitoring of pollution sources, conversion of wastewater treatment plants to advanced biological treatment, good agricultural practices and controlled fishing.
As part of the 24/7 inspection activities, it imposed an administrative fine of millions of lira, while many facilities were asked to suspend their activities.
With a team of 1,000 people, it ensured that thousands of cubic meters of mucilage were removed from the field and analyzed along with the surface cleaning of mucilage that prevents odor, image and light transmission.
Another important effect of mucilage is that it lowers the dissolved oxygen values in the environment it is in during decomposition.
In order to overcome this problem, the ministry is also evaluating the technological possibilities to increase the dissolved oxygen level in seawater above the hypoxia values, which are also implemented by some foreign countries.
Turkey carries out many studies within the scope of the protection of its Blue Homeland seas that surround us on three sides.
In order to prevent land-based waste from being transported by surface waters, the country has increased the rate of the municipal population receiving landfill services to 83%.
Turkey reduced the use of plastic bags by 75% by introducing a charge on them. The marine litter action plan of 28 provinces with coasts to the sea has been completed.
In this context, Turkey:
This incident witnessed in the Marmara Sea is not just today's problem. In fact, it is the result of many years of accumulation. It's a kind of reaction of the sea that has reached saturation.
The self-regulation mechanism in ecosystems makes it possible to cope with pollution of a certain value.
However, if the limit is exceeded, there is a constant accumulation. What we see here is a manifestation, an expression of years of accumulation.
Therefore, everyone needs to take responsibility for a healthy and permanent solution. Especially the country's local administrations.
As a matter of fact, what we are experiencing is not just an environmental problem. It resembles the COVID-19 pandemic to the extent that just like the pandemic, it has a multifaceted effect.
Environmental issues are above politics. Investments require continuity. Marmara is not just Istanbul, Tekirdağ or Bursa. It belongs to all of us.
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