The top levels of the Black Sea are less thick than its saltier bottom layers because rivers provide a plentiful supply of fresh water. Vertical mixing is prevented by a fixed border between the two. Oxygen, which is produced from the atmosphere through photosynthesis, is still limited to the surface waters. It can't penetrate more than a few hundred meters below sea level.
The Black Sea has no significant internal circulation. The water is warmed by the sun and cooled by winds at night. This process alone prevents large-scale movement. The water level is lowered about 20 meters (66 feet) around Mount Papa in southern Turkey. This is why the sea covers land that isn't submerged at high tide!
Oxygen is consumed as water vapor in the air. So, less rain means less oxygen for the sea. However, rivers do bring some oxygen down into the ocean. Some researchers estimate that about 10% of the river's flow reaches the deep ocean.
An average rainfall of about 40 inches (1 meter) per year causes hypoxia (low oxygen concentration) in the Black Sea. If it rains less than 30 inches (0.5 meter) per year, then it's considered hyperoxic (high oxygen concentration).
Although fish survive in some parts of the Black Sea, large predators such as tuna and shark have disappeared because there's not enough oxygen for them to live in.
Furthermore, a large quantity of hydrogen sulfide, a very deadly gas, is latent in the Black Sea's lowest strata. The hydrogen sulfide comes from anaerobic bacteria that thrive in these conditions.
The toxicity of the Black Sea arises not only from its high content of sodium chloride but also from its low pH and high temperature. These factors work together to destroy most forms of life, except for some deep-sea bacteria that can resist temperatures as low as 140 degrees Fahrenheit (60 degrees Celsius).
The Black Sea is one of the world's most toxic bodies of water. It contains high concentrations of mercury, which flows into it from coal mines and gold mines, as well as from natural sources. This poison kills both plants and animals that fall into it, including fish, birds, and other organisms that feed on them.
The combination of chemicals and heat present at great depths makes the Black Sea completely unsuitable for swimming. Although there are no official figures, it is estimated that between 20,000 and 50,000 people go swimming in the sea each year. Most of these people come from Romania and Russia, where they believe the water is warm even though it is actually cold.
The waters of the sea contain high concentrations of mercury and other toxic elements.
People can get sick from swimming in the Black Sea. Its waters are often contaminated with chemicals released into the environment during industrial processing or oil drilling. The sea also contains some dangerous bacteria that can make you sick if you swim in them. The most serious threat to health is the risk of drowning in these waters. People have died after entering the water in attempts to save others; they failed to reach the shore in time.
The best way to protect yourself against harmful substances in the water is by wearing a floatation device such as a life jacket when you go swimming. You should also stay within the marked lanes of the road while driving through any area where mining activities may occur. If you feel dizzy or nauseous, get out of the water immediately. These symptoms indicate that you are being exposed to too much hydrogen sulfide.
Swimming in the Black Sea should be avoided because there are better beaches nearby. Also, the sea contains pathogens that can cause you illness.
As a result, anoxic water makes up more than 90% of the deeper Black Sea volume. The circulation patterns of the Black Sea are principally influenced by basin topography and river inputs, resulting in a substantially stratified vertical structure. It is classed as a "salt wedge estuary" due of the high stratification. The highly saline surface waters lack oxygen due to low levels of sunlight that penetrate down to about 100 m depth where oxygen levels rise to approximately 5-10 ml per liter.
The Black Sea is a large body of water located between Europe and Asia. It has a total area of about 166,000 km2 and a maximum depth of 452 m. The sea covers parts of Bulgaria, Romania, Ukraine, and Turkey. It is connected to the Mediterranean Sea through the Strait of Gibraltar and to the Aegean Sea through the Danube River.
The Black Sea contains roughly 30 million tonnes of salt (equal to one fifth of all the salt in the Earth's oceans) and its average density is only 1/3 that of seawater. These characteristics make it very inhospitable to live things. Fish do not normally survive in the Black Sea because they cannot cope with its conditions. However, there are some fish species that can adapt themselves to these harsh conditions. Shellfish can also be found in the sea but their population is dominated by algae and cyanobacteria which collect food from the sediment. This forms a thick layer of scum that prevents any light from reaching the bottom.