Salt Water
The natural phenonemon of the Dead Sea has long been known, with ancient writers referring to it either as the Salt Sea or as Lake Asphaltis, both names deriving from the two unusual features of the lowest lake on earth.
The unusual saltiness of the Dead Sea has been commented upon by many; Josephus tells of how Vespasian conducted a scientific experiment by tying together two slaves who could not swim and throwing them in to prove that they could not sink! The famous Madeba Map has fish dotted along the length of the Jordan River, all swimming downstream apart from the last one, which is shown heading upstream away from its first taste of the Dead Sea!
According to conventional wisdom, the Dead Sea is salt because, over tens of thousands of years the River Jordan has carried a burden of minerals down into the sea. As there is no outlet from the Dead Sea, all this water has evaporated, leaving the minerals behind, hence the saltiness of the water. A recent discovery up at the Lake of Galilee has provided an indication that there may be another explanation and a shorter timescale.
Jordan water flowing into the Lake of Galilee carried 20 milligrammes of chloride per litre, yet the water in the lake itself bears 385 millgrammes per litre. Water from this ostensibly "fresh water" lake is sufficiently salty that it must be diluted with pure water before it is suitable for drinking — and Galilee water is polluting fields in the Negev with a salt crust that has to be washed away with more of the precious pure water.
Twenty years ago scientists noted the high salt content of some springs on the western shore of the lake. These were diverted and an immediate improvement in water quality in the lake was noticed, with chloride levels falling to 240 milligrammes per litre — still too salty to drink, but a definite improvement.
Now researchers from Leeds University, working with the Lake Kinneret Research Laboratory and the Weizmann Institute, have discovered another source of the lake‘s saltiness: underwater springs. So far they have located three large ones, all near the western shore line. In one place the chloride level leaped to 10,000 milligrammes per litre just four inches below the lake bed. The scientists are now trying to work out how they can cap these springs and prevent their water flowing into the lake.
Their desire to improve the water quality may backfire, however. The areas where the springs come to the surface are particularly rich in fish, probably attracted there by the slightly warmer water. Anything that might harm the important fishing industry is unlikely to gain wide-spread approval from those who live around the lake.
