Jellyfish lab

In the newly opened laboratory, the breeding of different types of jellyfish and other gelatinous organisms such as the sea walnut (Mnemiopsis leidyi) is demonstrated.

The Aquarium Pula exhibits about fifteen species of jellyfish and another twenty species of polyps. Visitors can learn about the different stages of their life cycle and their feeding habits.

Scyphoza

Scyphozoans, commonly known as jellyfish, are gelatinous planktonic organisms that belong to the phylum Cnidaria. Like other members of this phylum, they possess stinging cells (cnidocytes). About 200 species have been described and are found in all oceans. Most scyphozoans have a complex life cycle that includes a polyp stage (asexual generation) and a medusa stage (sexual generation). However, some scyphozoans, such as the moon jellyfish, only occur in the medusa form, while others only exist in the polyp form. Almost all medusae are planktonic, which means that they live in the water column and move with the currents. However, species such as the upside-down jellyfish (Cassiopea xamachana) spend most of their lives on the sea floor.

Jellyfish in the ecosystem

The increase in the number of jellyfish indicates changes in the ecosystem caused by natural processes and/or anthropogenic disturbances such as climate change, overfishing, excessive urbanisation and eutrophication, i.e. the accumulation of nutrients in the water. The increase in their numbers could play a positive role in the ocean's carbon cycle. As planktonic organisms, jellyfish feed on organic particles in the water column and take up organic carbon. When they die, these organisms settle on the seabed where their bodies decompose, releasing carbon that is deposited on the ocean/seafloor. Jellyfish thus participate in the transfer of carbon from the water to the seafloor, affecting the global carbon cycle and biochemical processes in the oceans.