Why would anyone call a sea “dead”? When you think about it, ALL seas are dead, right,
on the account of not being “alive”? So why did we ostracize this particular sea and call it dead?
And that’s not even the weirdest part! Did you know that anyone can float in the Dead Sea, even
if they don’t know the first thing about swimming? For those reasons and more,
it’s due time to talk about the DEAD SEA! The hypersaline Dead Sea is one of the most
intriguing places on our planet. From being surprisingly bereft of the usual flora and
fauna to being a source of medicinal and therapeutic remedies, this sea piques the
interest of tourists and researchers alike. It is located in the centre of a geological rift,
the Jordan Rift Valley, bordering Israel on the east and Jordan on the west.
Most of the enigmatic aspects of the Dead Sea, from its morbid name to the natural buoyancy it
offers, is directly linked to its hyper salinity. Salt and other minerals that are in abundance in
the Dead Sea are derived from rock erosion by rainwater. During heavy rains, water molecules
in the rainwater react with the carbon dioxide in the atmosphere to form carbonic acid, which
makes the rainwater slightly acidic. This acidic rainwater then reacts with rock in the hilly area
near the sea and erodes it. This erosion is a slow and continuous process that leads to the formation
of salt and other minerals, which are then carried to the Dead Sea through runoff from the rocky
regions. This is the source of the salinity of the Dead Sea. In fact, this explanation applies
to the salinity of other water bodies as well. However, the Dead Sea is MUCH MUCH SALTIER than
your average ocean. It is one of the saltiest lakes in the world, boasting salinity levels above
34%. Calling it a sea is actually a misnomer, as it is landlocked at the lowest point on Earth,
with shores approximately 430 meters below sea level. The salt accrued here is TRAPPED
and cannot easily escape. Moreover, relatively high atmospheric pressure, elevated temperature,
dry air, and low rainfall make the Dead Sea much saltier than any other water body.
Now, the main question is why do you naturally float in the Dead Sea? The science behind this
again lies in the HIGH SALINITY. With more than 340 gms/kg salt content, along with a high amount
of other minerals, the water in the Dead Sea is denser than other water bodies. On average,
sea water contains 35gms/kg salt. As you can clearly see, the “dead” water is roughly 10 times
saltier than what we find in other water bodies! There is a direct relationship between salinity
and density. The higher the salinity, the greater the density of the water. When we
say that salt water is denser, we mean that there is MORE mass per volume. Basically,
when the salt (NaCl) is mixed with the water (H2O), it dissolves into ions of sodium and
chloride. The addition of salt in the water increases volume by a small factor, but it
increases mass by a large amount, simply because NaCl is much denser than H2O. Its ions—sodium and
chloride—have significantly more mass than the atoms of oxygen and hydrogen. Thus, when salt
dissolves in water to form ions, it increases the overall density of the dissolved water.
With salinity 10 times higher than a typical sea, the water of the Dead Sea is really dense—1240
kg/m3 to be precise. The human body’s density, on the other hand, is only 985 kg/m3. Therefore,
when we go for a swim in the Dead Sea, our body stays afloat on account of having RELATIVELY
lower density than the surrounding water. When an object is immersed in the water,
the water exerts an upward force, called up thrust, on the object in question. If
the density of the immersed object is less than the water, then this up thrusting force triumphs
in keeping the immersed object floating on the surface. That’s exactly what happens in
the Dead Sea! Due to the high salinity, the water is so dense that our body experiences
a powerful buoyant force in the hypersaline water. That’s why we float effortlessly in the Dead Sea.
Owing to the high density, it is quite improbable to drown in this hypersaline sea. Even so,
some people have lost their lives in the Dead Sea. It’s perfectly safe to float normally,
reclining on your back with your head held above the sea water, but if you trip and fall,
dropping your head under the water, it becomes far more risky. You then run
the risk of swallowing a lot of saline water, which could disrupt the electrolyte balance of
your body. A massive proportion of salt intake adversely affects the HEART and KIDNEY, which
could ultimately be fatal. Deaths that occurred while unwinding in the Dead Sea were often found
to be linked with this type of salt poisoning. That’s why it is highly advisable to only go
in the Dead Sea when lifeguards are around, wear protective eyeglasses,
and definitely avoid immersing your head beneath the surface.
If you can take these basic precautions, floating naturally without a life jacket
on a sea at the lowest point on Earth is truly an unforgettable experience.