47-meter-long tubular jellyfish filmed in the deep sea off Australia, how does it move and feed?

Jellyfish are very beautiful aquatic animals and important plankton in aquatic environments, with many species. Recently, Australia filmed a 47-meter-long tubular jellyfish in the deep sea! So how does it move in the water? What does it feed on?

1. Australia filmed a 47-meter-long tubular jellyfish in the deep sea!

The Schmidt Ocean Institute shared a rare video on overseas social media of an Apolemia jellyfish (a type of siphonophore). This jellyfish is like a long rope floating in the sea. It is reported that the video was filmed in the Ningaloo Canyons off the west coast of Australia. Scientists used lasers to determine the size of the outer ring and estimated from its diameter that it was 154 feet long (about 47 meters).

2. How do jellyfish move in the water?

1. Movement

Jellyfish move by contracting the outer bell to squeeze the inner cavity, changing the volume of the inner cavity, ejecting the water inside the cavity, and propelling themselves by jetting water. Muscle fibers in the jellyfish epidermis, extending from the top to the end of the bell, control the contraction and expansion of the inner cavity. When the inner cavity expands, water is slowly drawn in and fills the cavity; when the inner cavity rapidly contracts, the water is squeezed out of the cavity, and the thrust generated by the jet of water moves the jellyfish along the axial direction of its body.

2. Sinking

When a jellyfish tries to sink in the water, its tentacles stretch out and point upward, forming long lines; when it intends to rise or move in a certain direction, the far ends of the tentacles bend against the direction of movement. With the help of its tentacles, the jellyfish effectively changes direction. Jellyfish are not good swimmers; they often rely on wind, waves and currents to move.

3. What do jellyfish feed on?

All jellyfish are carnivorous, feeding on plankton, small crustaceans, polychaetes and even small fish. Mechanical and chemical stimulation from food causes cnidarians to extend their tentacles and release nematocysts to entangle, paralyze and kill prey, then deliver the food to the mouth.

4. What should you do if you are stung by a jellyfish?

Jellyfish are found in every ocean in the world, and they even appear in some freshwater lakes and ponds. Many neurosurgeons say that commonly used pain remedies such as vinegar, urine or fabric softener do not help with the sting. Instead, the best approach is to rinse with salt water. Salt water deactivates the stinging cells, while fresh water or tap water reactivates them.

Although jellyfish are beautiful, they are venomous. Generally, when stung by a jellyfish, you will only feel a burning pain and see redness and swelling. As long as you apply anti-inflammatory medicine or vinegar, the swelling and pain will subside after a few days. But if the situation is serious, it is still recommended to go to the hospital immediately.