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Welcome to the weird and wonderful world of Jellyfish Lake.
This marine lake is situated on Eil Malk, an island in Palau, in the Pacific Ocean. It is encased by limestone, and hence fractures and fissures within the rock structure have allowed for the intrusion of seawater, which is just a few metres away.
Black Sea not site of Noah's flood.
In recent years the controversial hypothesis that the biblical event was a transmitted oral memory of the catastrophic flooding of the Black Sea by post ice age rising sea levels has been advanced, notably by Robert Ballard of Titanic fame. While it is clear that the freshwater lake did fill with salt water around 12000 years ago, and that people had lived around it and moved away, new geochemical evidence published in Geology implies that this rise was gradual rather than sudden. The lake's chemistry changed from oxygenated to anoxic during this transition, as the sea spilled over the Bosporus sill (a natural dam of intruded igneous rock). Currently the chemocline between oxygenated surface fresh water and deeper salt anoxic water is at 150M, and the surface water from rivers is exchanged for salt water from the Aegean.
Researchers used a combination of iron isotopes (to trace the changes in oxygen levels) and molybdenum (to trace changes in salinity) in sediment cores to reconstruct the history of the lake's evolution and gradual conversion to anoxic conditions. The results showed that the change had happened over thousands of years, between 12,000 and 3,000 BCE.
On another note, the image shows phytoplankton blooms in the Black Sea, due to fertiliser runoff flowing down the Danube, Don and Kuban rivers. Following the current flooding in Central Europe, another large bloom is a near certainty, which will temporarily change the level of the chemocline.
Loz
Image credit: MODIS/AQUA/NASA
http://geology.gsapubs.org/content/41/4/523.full#ref-7 http://geology.gsapubs.org/content/41/4/431 Tag Photo
