Hundreds of enormous craters gushing fresh water and filled with germs have been discovered at the typically desolate bottom of the Dead Sea, according to new study. The findings add to evidence that the dead sea is more than just a salt lake. It's also a mountain range, with many canyons and ravines.
The research was led by Lidija Stojanovic of Columbia University's Lamont-Doherty Earth Observatory. She said she was surprised by the number of ponds found at the bottom of the sea. "I didn't expect to find so many large bodies of water," she told NBC News. "They cover an area of about 10 square miles."
The team used satellite images to identify the fresh water features at the bottom of the sea. They then collected water samples from several sites to test them for bacterial activity. All of the samples contained high levels of oxygen and low levels of nutrients that are usually found in lakes but not in the Dead Sea. This showed that there is a lot of life in these waters even though they are very salty.
Stojanovic said this proves the sea has been reusing its water for thousands of years. "This shows that the Dead Sea is much more than just a salt lake," she said.
The sea is referred to be "dead" because of its extreme salinity, which precludes macroscopic aquatic animals such as fish and aquatic plants from thriving there, despite the presence of trace amounts of bacteria and microbial fungus. The concentration of salt in the water is so high that it prevents most living organisms from surviving in it.
However, a few species of microorganisms can grow in the salty waters of the Dead Sea. These include bacteria, fungi, and algae. There are also small amounts of plant material (mainly decaying wood) that have drifted into the lake from surrounding areas.
The lack of competition allows these microorganisms to thrive in an environment that would kill most other organisms. For example, bacteria can use the salt for food and multiply rapidly; then, when they die, they decompose and add more nutrients to the soil.
Algae can grow in the Dead Sea due to the lack of nutrients and sunlight. However, unlike plants that require soil to survive, algae can live solely on solar energy while consuming carbon dioxide during the day and releasing oxygen at night. Since algae cannot move away from direct sunlight, they tend to cluster together and fall over in strong winds, forming large patches of color in the water.
Fungi play a role in breaking down debris that ends up in the Dead Sea.
Since then, the Dead Sea has been growing drier and drier as more water evaporates than is replenished (the sea's water level drops by around four feet per year). However, the Dead Water's high and variable salinity causes all sorts of strange bacterial growth, such as the algal blooms that painted the sea red in 1980 and 1992. This raises some interesting questions about salinity and ocean currents. Does the flow of salt water affect the distribution of organisms in its path? What role does salinity play in determining which parts of the ocean are inhabited by different species?
The answer to both questions is yes. The presence of salt inhibits the growth of most organisms, so they will prefer fresh water over salty water. This is why lakes and seas contain a wide variety of life: because it's possible for many different types of organisms to exist together in one environment. There are also other factors at work - temperature for example- but salt concentration is very important.
So how does this affect what lives in the Dead Sea? Well, any organism that cannot overcome the high concentration of salt in the water will die. This includes all marine creatures except for those that can produce proteins that allow them to bind together with their arms and legs folded in a kind of crystal structure called a "salt gland". These include certain bacteria and archaea (kinds of ancient organism) as well as animals from the family Crustacea (such as crabs and shrimp).