It’s the second day of our PADI Advanced Open Water course, and today we completed our deep dive and navigation specialities while continuing to practice the peak performance buoyancy skills that we learned yesterday.

For both the deep and navigation dives we have to learn a lot of different things. But there is one skill that is common to both: descending! We cannot dive if we cannot descend, of course.

As part of the deep dive course, our dive instructor Rian explained that we will experience greater pressure with depth. Some of the biggest effects of this pressure change are felt when descending from the surface to 10 meters, as the pressure change will cause gas volumes to be reduced by half.

As we all have air spaces in our bodies called sinuses, divers must take steps to equalize the pressure as they descend. The most common way is to pinch your nose and blow. Another way is to pinch your nose and swallow.  Both these techniques open the Eustachian tubes and equalise the pressure in the inner ear. You can learn more about how to equalise your ears from Divers Alert Network.

Do you spot something? Equalising depends on your nose. If something bothers your nose it can certainly disturb your equalisation. Rian explained that simple things like a cold, hayfever or influenza can be a big problem for divers. If your upper respiratory system is irritated it can swell and become congested with mucus, blocking your Eustachian tubes and sinuses. This can make it very difficult to equalise your ears and sinuses, and if you are not careful can even result in pain, injury or permanent hearing loss. 

When we learned this it crossed my mind that staying healthy is so important, especially when you do dangerous work or sports such as diving. We should all think carefully about what we eat and how much rest we get, to ensure we stay healthy all the time. We don’t want to miss seeing the mantas because we are unhealthy, so I’m going to make sure that I eat lots of fruit and vegetables this month!



I am an undergo undergraduate student from IPB University majoring Marine Science and Technology. I conduct my final project about the use of metabarcoding eDNA for searching biogeography and relative abundance of endemic species walking shark Halmahera. I have strong interest in conservation, specifically elasmobranch conservation for sharks and rays.