Tag Archives: Pressure

Under Pressure

The Deepest part of the ocean is about 36,200 feet or over 11,000 meters, which is deeper than Mt. Everest is tall by about 7,000 feet! Animals that live this deep have a remarkable amount of challenges that they have to adapt to in order to live, such as absence of light, freezing temperatures, and immense increases of pressure. Today we are going to talk about why pressure is increased as you go deeper as well as the effects that it has on many animals that live down there.

Have you ever been on a snorkel or a SCUBA dive and felt pressure on your ears as you go deeper down? Well, if you have, that is actually the air cavities inside your ears shrinking as you go deeper. As a rule of thumb the deeper you go in the ocean the more pressure is being forced onto your body. We normally measure pressure in atmospheres, which is the amount of pressure exerted by the Earth’s atmosphere. At the surface of the ocean we only have 1 atmosphere of pressure pushing down on our bodies. Each atmosphere is equivalent to 14.5 pounds per square inch, meaning you have 14.5 pounds of force pushing down on you right now. However, as you descend in your SCUBA unit or pressurized submarine, the pressure increases by 1 atmosphere every 10 meters (33 feet). So, at the deepest depths of the ocean, you have the weight of an elephant on every inch of your body, OUCH!

So how can animals that live and thrive in the deep depths of the ocean survive these immense pressures and we cannot? Inside of our bodies we have many air cavities that would pop and rigid bones that would snap when exposed to the pressure. So for invertebrates and fish that live in the Marianas Trench the simple solution is to remove the air cavities and have very flexible bones…if any at all! Fish do this by evolving past swim bladders, an organ that normally controls buoyancy. Many invertebrates do this by having hydrostatic skeletons; a fluid filled cavity surrounded by muscle, or no air cavities as well. Marine mammals like deep diving whales have incredibly flexible rib cages that can compress with the pressure and collapsible lungs that can withstand rupturing! This is exactly how Sperm Whales are able to dive down to 7,000 feet deep to battle and eat Giant Squid.


Equalize Early and Often

Have you ever wanted to dive below the surface of the water? If so, it’s important to learn more about equalizing. As you descend, pressure builds up in the inner and outer parts of your ears, which at a few feet can be uncomfortable, but a bit deeper, can lead to major ear damage. Equalizing balances out that pressure, and opens something called the Eustachian tubes, which connect to the empty air space of the middle ear. Throughout our daily lives, we are often equalizing the pressure in our ears by simply swallowing or yawning. When we dive underwater however, we often need a more deliberate method to make sure that the pressure becomes equalized.

IMG_4356One of the most common techniques for equalizing underwater is something called the Valsalva maneuver. For this method, you simply pinch your nose, keep your mouth closed, and blow out. The high amount of pressure in your throat then prompts the Eustachian tubes to open and equalize the pressure in your ears. This method is one of the first that is generally taught to new divers, but it is important to understand that there are still risks. Making sure not to blow too hard can help to prevent damage to the round and oval windows in the inner ear. Other common equalizing techniques include the Toynbee Method, the Lowry Technique, and Voluntary Tubal Opening, among others. For the Toynbee Method, the nose is pinched, and the diver swallows to open the Eustachian tubes. The Lowry Technique combines both the Valsalva and Toynbee methods by pinching the nose and then blowing out and swallowing at the same time. As divers practice equalizing, they may become more comfortable with a specific technique, or learn to control their muscles especially well. For Voluntary Tubal Opening, a diver may learn how to continuously equalize the pressure in their ears by tensing their throat and jutting their lower jaw forward and down similar to a yawn.

So when do you equalize? The most important things to remember are to equalize early and to equalize often. If you have a dive planned for later in the day, it is a good idea to start equalizing a few hours beforehand every few minutes. Before going underwater, always equalize on the surface. Then, as you descend, make an effort to equalize about every two feet to avoid the tearing of tissue or eardrum damage. If at any point your ears hurt, make sure you don’t push through the pain and continue to descend. Equalization takes practice, but diving underwater can take you to a whole new world in the ocean!

Written by: Jaclyn Lucas


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