Jellyfish of the Rhizostomeae Family: Swimmers and Symbiotics

Have you ever wondered why some jellyfish are bigger and seemingly speedier than others? The Rhizostomeae family, often known for their large sizes and distinctive body shapes, has grabbed the attention of scientists due to their impactful blooms in coastal areas worldwide. As a result, researchers have been delving deeper into the intricate workings of these fascinating sea creatures. One interesting fact is that Rhizostomeae jellyfish have more than double the carbon content per unit of biomass compared to their Semaeostomeae cousins. They are also quite the speed demons, swimming about twice as fast and consuming more oxygen than other similarly-sized scyphozoans. When it comes to growth, they're the champs, exhibiting faster initial growth in labs and the highest growth rates observed in nature compared to other medusae groups.But speed and size aren't everything. These jellyfish also have unique physiological features influenced by symbiotic zooxanthellae found in species of the Kolpophorae suborder. This symbiotic relationship impacts their body composition, nutrition, and excretion, showcasing how partnerships in nature can significantly shape an organism's biology. However, it's essential to note that our understanding is still limited, based on studies of only a few species. The data we do have suggest that Rhizostomeae jellyfish have a higher energy demand and body productivity compared to other jellyfish groups. Understanding these unique characteristics can help scientists make more informed predictions about how these jellyfish interact with their ecosystems.