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PEANUT BUTTER JELLY TIME: THE
Jellyfish may be transparent in structure, but their value to marine ecosystems is certainly anything but. Jellyfish are made up of a hydrostatic hollow skeleton called the mesoglea. This is a combination of 95% water, as well as collagen, fibrous proteins, and wandering amoebocytes for debris and bacteria collection. This may seem like a strange composition for an animal; however, jellyfish are incredibly unusual- they do not possess a brain, blood, or heart. They are actually a type of zooplankton with an umbrella-shaped bell; the mesoglea creates a light, delicate jelly-like texture that facilitates sea travel. This structure permits jellyfish to go with the flow, drifting with ocean currents. Plankton are a key component in the diets of many marine organisms. Some fish, sea turtles, crustaceans, and even people include jellyfish in their diet. Conversely, jellyfish cannot track their prey; they have to pull in with their tentacles whatever is floating within reach. That said, they have a large stomach compartment that requires frequent refueling. Smaller jellies target miniscule organisms, including algae and zooplankton, while larger species ingest shrimp, fishes, and even other jellyfish. Their constant eating helps control populations of low trophic level species, which is vital to maintaining ecosystem balance.
As a simple creature, many jellyfish body parts are multipurpose. For example, the tentacles capture food and aid with movement. The mouth acts as both the entry point for food and the exit for waste. Jellyfish feces becomes fertilizer for plants and small sea creatures in the depths and on the sea floor. This too helps sustain the ecosystem. Another special adaptation of jellyfish is their stinging cells, or nematocysts. Jellyfish bloom. By: UBC Media Relations, Flickr.
Jellyfish use their stinging powers to incapacitate their prey and also to protect certain species of juvenile fish that hide within the tentacles. These young fish are from species which produce a mucous that protects them from the jelly’s venom. Seeking shelter among the tentacles allows them to grow and helps replenish stock levels. Even in death, jellyfish are working to balance the marine ecosystem. Jellyfish usually die due to a clogged feeding area, lack of food when blooms are exhausted, parasites, bodily injury from predators, or sudden temperature changes. When jellyfish begin to decompose, they sink. These descents through the water column are called jelly-falls. The size of jelly-fall depends on the cause of death. Single deaths create smaller jelly-falls, which can be devoured by scavengers in under three hours. Sea stars are the main species that benefit from these falls. Others include fish, shrimp, and lobsters. Jelly-falls can occur wherever jellies are found, and the rapidity of decay is temperature dependent. The falls distribute carbon on the seafloor, offering nutrition to bacteria and benthic megafauna. Because of this, jelly-falls are considered a significant biological carbon sequestration. Locations with warmer waters and jelly bloom hotspots experience more extreme jelly-falls. A 2016 study found that these falls played a role in the biochemical process within benthic communities. When scavengers are not involved, the decaying corpses’ sulfide is expelled as a black residue that is engulfed by a layer of white bacteria. The process pulls large quantities of oxygen from the ecosystem and transforms the falls into hypoxic droppings unwanted by bigger scavengers. Unlike many organisms that are at risk of extinction, jellyfish populations are on the rise. More jellies means more frequent blooms and, in turn, more jelly-falls. As climate change continues to cause ocean acidification and warmer waters, jelly populations are predicted to experience population surges. In addition, eutrophic areas, or waters with sub-average oxygen levels, are popular hot spots for jellies and associated blooms. Jellyfish in life, as in death, are important components of their marine ecosystem. These small drifters help rebuild fish stocks, control smaller species growth, and provide vital nutrients in jelly-falls.
