While death is a universal feature of life, one jellyfish species has discovered an exceptional method of surviving it entirely.
Researchers at the University of Oveidas in Spain studied Turritopsis dohrnii, also known as the immortal jellyfish, to figure out how its unique ability came about.
The lifecycle of a jellyfish
We must first look at how regular jellyfish age in order to comprehend how the immortal jellyfish has done it.
Jellyfish start out as larvae that float through the ocean before sinking to the bottom to find a surface on which to attach. They develop a digestive system and feed on zooplankton here, resulting in a polyp. At this point, their only objective is to survive.
When the water conditions are ideal, the polyp will sexually reproduce and generate genetically similar copies in rapid succession.
Before immature medusae – the typical jellyfish forms we are used to seeing in the ocean or washed up on our beaches – bud off from the polyps, a colony can cover a whole boat dock in only a few days.
Medusae that live freely in water disperse and reproduce, spending only a few months alive. Most jellyfish are done here, but the immortal jellyfish has the potential to go back into this cycle.
T. may react to illness, injury, or old age by experiencing environmental stress. The seabed will reattach itself to the dohnii, regressing into a polyp, and the cycle will begin again when dohnii falls to the ocean bottom and changes into a cyst.
How long can the immortal jellyfish live?
Given that these creatures have existed in the oceans for more than 500 million years, this cycle of regeneration could theoretically go on forever, and a single immortal jellyfish may have lived this entire time.
Yet, since these jellyfish have only been studied for a few decades, scientists have a limited amount of data to work with, making it difficult to prove this is technically feasible.
While a single colony was kept alive in Japan for two years, the jellyfish are also incredibly difficult to maintain alive in captivity. It regenerated itself 10 times throughout this period (source).
The science behind their immortality
Researchers at the University of Oviedo in Spain studied the genome of the immortal jellyfish and compared it to that of a close relative, the crimson jellyfish (Turritopsis rubra), in order to explain how it accomplishes this incredible feat.
The genes that cause DNA repair were discovered to be doubled in number in the immortal jellyfish, indicating that the jellyfish can create bigger amounts of restorative and protective proteins.
Furthermore, the scientists discovered distinct mutations that inhibited cell division and blocked the deterioration of chromosome telomeres, known as telomeres. Maintaining telomere length in humans may be one of the keys to slowing aging (source), since it decreases with age.
Could humans live forever?
Humans are a long way from any kind of real-world application for the discovery of the immortal jellyfish, which has mastered this ability. The goal is to expand our knowledge of cellular and tissue regeneration by investigating what occurs in the jellyfish and how their genes manipulate cells.
This may have relevance to human aging in the future, possibly influencing regenerative medicine and providing information into age-related illnesses like cancer and neurodegeneration.
Other jellyfish discoveries
Many other species have been researched for a variety of medical applications, and the immortal jellyfish isn’t the only one with unusual characteristics.
Venom from the Acromitus flagellates jellyfish, according to new study, may be utilized as a possible cancer therapy since it slows and even reverses the development of tumor cells in human livers and lungs (source).
Aequorea victoria, a different species, has the most thoroughly investigated and extensively utilized medical diagnostics protein, green fluorescent protein (GFP).
GFP can be used as a reporter for identifying which genes are being expressed when it is inserted into DNA (source). This approach is becoming increasingly popular for studying signaling pathways in cells, which will help us understand how cells work and may aid drug development.
By using green fluorescent protein (GFP) to investigate cancer, researchers may monitor and investigate the spread of cancer cells inside animals (source).
The worldwide jellyfish threat
While the scientific benefits of these creatures cannot be ignored, increasing numbers of jellyfish pose a danger to humans in the ocean.
Every summer, millions of jellyfish swarm along Israel’s shore, clogging power plant filters, posing a danger to beachgoers, and costing $10 million in lost tourism.
Jellyfish populations are rising across the globe, and bigger blooms are becoming more prevalent in their natural habitats. The issue isn’t limited to Israel.
Due to swarms of jellyfish blocking their water intakes, several power plants and desalination facilities in numerous countries have had to shut down temporarily.
By obstructing nets and attacking fish farms, mass jellyfish blooms harm commercial fish species larvae recovery, as well as damaging fisheries.
Jellyfish stingings affect an additional 150 million people each year, with 100 of them dying as a result.
Why are we seeing more jellyfish blooms?
The dispersion of species across the globe increases as global commerce grows. Around 7,000 species are believed to have been transported to new habitats via commercial ships’ ballast water discharge, upsetting the ecological equilibrium of local ecosystems.
Five species of jellyfish have currently made their way up the Suez Canal from the Red Sea, causing frequent, and significantly larger, bloom episodes in the Mediterranean.
The increase in jellyfish isn’t solely due to shipping. Jellyfish populations are unchecked because of overfishing of predators, and jellyfish can expand their ranges thanks to rising seas caused by climate change. Agricultural runoff has killed competing species, and the rise in plastic pollution gives them a greater chance of going unnoticed by predators.
Certain jellyfish species have been discovered to form new populations in previously uninhabited areas thanks to offshore wind farms and oil platforms, which act as incubators (source).
What does this mean for the environment?
Jellyfish are designated as “indicator species,” implying that variations in their population may foreshadow alterations in the ecosystem with devastating consequences.
A bloom of the northern sea nettle (Chrysaora melanaster) ate around 32% of the yearly zooplankton stock in the Bering Sea in 1999, compared to less than 1% in non-bloom periods.
Jellyfish may outnumber fish populations after they have gained a foothold, limiting the amount of prey available to them and potentially altering their population size (source).
Jellyfish blooms are generally short-lived, dissolving when water temperature, oxygen concentrations, or the life cycle of the jellyfish itself changes.
The organic matter released from these flowers is swiftly decomposed, and it feeds microbial communities and refreshes the seabed.
Low oxygen zones that are only accessible by the bacterial community may occur in certain situations when the additional organic matter is too big for these communities to breakdown. As a result, energy is transferred to those higher in the food chain, resulting in a trophic dead end (sources).
A Silent Invasion
The immortal jellyfish is practically invisible and defies mortality. It’s just 4.5 millimeters broad, barely bigger than your thumbnail, and it may be found in temperate and tropical seas all around the world if you look closely enough.
T is the symbol for the fourth dimension, time. Dohrnii is thought to be the first species of genetically identical jellyfish to bloom in the Pacific, however it has since spread throughout the globe and split into various populations.
The Jellyfish seems to have spread primarily due to the cysts from which it grows, which are discovered at considerably lower depths than ocean currents. As a result, it is thought that the species was carried across the globe by ships.
Because any damage sustained in transit can be easily reversed, the immortal jellyfish makes an excellent hitchhiker (source).
The immortal jellyfish had a tiny distribution and has little impact on the world’s oceans, thus its effect went largely unnoticed.
Although the species has not been documented causing disruption or harm during massive bloom occurrences, the overall effect on ecosystems and food chains is unclear.
Can the immortal jellyfish die?
Immortal jellyfish are vulnerable to predators, even when they are older or harmed. The polyps are eaten by sea slugs, and the medusae is consumed by a variety of predators.
The jellyfish isn’t indestructible, so the species is unlikely to overrun the planet in the near future.
With the peculiar biology of these creatures opening multiple avenues for scientific study and medical innovation, we can profit greatly from the immortal jellyfish and its relatives.
Yet, the species’ growing presence across the globe cannot be overlooked, since it demonstrates our misunderstanding of how human activity has pushed our oceans out of equilibrium.