Jellyfish

Image of jellyfish captured in glass filming vessel. The footage below shows a jellyfish swimming through a laser sheet with tracer particles.
Image of jellyfish captured in glass filming vessel. The footage below shows a jellyfish swimming through a laser sheet with tracer particles.

Jellyfish creates virtual floor to swim efficiently

Researchers have known that an animal swimming parallel to a solid surface receive a subsequent boost in performance, thus allowing them to utilise less energy when moving around. 
 
Studies have quantified this into a 25 percent increase in speed and a 45 percent increase in thrust when swimming near a solid surface. 

However, the jellyfish does not swim near the seafloor or seawalls. How does it get named the "world's most efficient swimmer"?

Apparently, it does so by creating a "virtual wall."

Here's what the Cassiopea xamachana jellyfish looks like. Photo taken at aquarium in Loro Parque

How upside-down jellyfish can make the water sting

In some tropical waters like the Florida Keys mangrove forests, for snorkellers to stay safe, it’s not enough to not touch anything. It may not be a good idea to enter the water in the first place.

That’s because sometimes it seems that the water itself can sting, causing rashes on a snorkeller's skin.

Here's what the Cassiopea xamachana jellyfish looks like. Photo taken at aquarium in Loro Parque
Here's what the Cassiopea xamachana jellyfish looks like. Photo taken at aquarium in Loro Parque

How upside-down jellyfish can make the water sting

In some tropical waters like the Florida Keys mangrove forests, for snorkellers to stay safe, it’s not enough to not touch anything. It may not be a good idea to enter the water in the first place.

That’s because sometimes it seems that the water itself can sting, causing rashes on a snorkeller's skin.

Periphylla: Aliens of the Deep

The jet-black rubber RIB was running flat out in the February night. We were sweeping past the Mongstad oil refinery at the Norwegian west-coast, just south of Gulen Dive Resort, and the clock was approaching midnight. Apart from the lights in the distance, the visibility was zero, and we were navigating solely on GPS, chart plotter and radar.