Jellyfish: Mysteries of Ancient Creatures and New Ocean Discoveries

Jellyfish are among the most mysterious and ancient inhabitants of our planet. Their evolutionary history stretches back over 600 million years, making them older than dinosaurs and even most multicellular organisms. These soft, transparent beings, lacking bones, hearts, or brains, continue to inspire awe and scientific curiosity. Despite their seemingly simple anatomy, jellyfish play a vital role in the ecosystems of the world’s oceans, influencing food chains, climate processes, and even biotechnology.

Modern research reveals that jellyfish are far more than brainless drifters. They are remarkably resilient organisms, capable of surviving in extreme environments. From warm tropical lagoons to icy Arctic waters, from the ocean surface to depths of several kilometers, jellyfish have colonized nearly every marine habitat. Studying them has become essential not only for understanding marine biology but also for tracing the evolutionary mechanisms that shaped life on Earth.

Origin and Biological Features of Jellyfish

Jellyfish belong to the phylum Cnidaria, which also includes corals and hydroids. Their bodies are structurally simple: a bell (or umbrella) and dangling tentacles. Inside lies the gastrovascular cavity, which serves as both stomach and circulatory system. Although they have no brain, jellyfish possess a nerve ring that coordinates movement and responses to stimuli.

One of their greatest secrets of survival lies in their extraordinary ability to regenerate. Some species, such as Turritopsis dohrnii, can revert from the adult medusa stage back into a polyp—essentially reversing aging and achieving a form of biological immortality. Scientists study this phenomenon intensively, hoping it may one day unlock new insights into aging in other organisms.

Jellyfish also display remarkable adaptability. Their gelatinous bodies are composed of 95–98% water, allowing them to endure dramatic changes in pressure and temperature. They can even thrive in oxygen-poor environments that would kill most marine animals.

This simplicity is their strength: when other species decline under pollution and climate stress, jellyfish populations often expand. In some regions, such as the Yellow Sea and the Sea of Japan, they have become dominant species, posing challenges for fisheries and marine ecosystems.

Jellyfish and Humans: Biology, Benefit, and Danger

The relationship between jellyfish and humans is deeply ambivalent. On one hand, they inspire art, technology, and science; on the other, they can disrupt economies and pose health risks.

Some jellyfish—especially the cube-shaped Cubozoa—possess extremely potent venom. The sting of the Australian box jellyfish (Chironex fleckeri) can stop a human heart within minutes. Even less deadly species can cause painful stings and allergic reactions, sometimes affecting entire coastal industries dependent on tourism and fishing.

Yet jellyfish are also immensely valuable for scientific research and innovation. From the jellyfish Aequorea victoria, scientists extracted the Green Fluorescent Protein (GFP), a discovery that earned the 2008 Nobel Prize in Chemistry. GFP has since become a cornerstone of molecular biology, allowing researchers to “light up” living cells and observe their inner processes in real time.

In Asia, jellyfish are also a culinary delicacy and a source of collagen used in cosmetics. Recently, jellyfish-derived collagen has attracted interest in biomedical engineering as a sustainable and biocompatible material.

Thus, jellyfish embody a paradox: at once dangerous and useful, ancient yet relevant, primitive yet technologically inspiring.

Discovery of New Jellyfish Species

With advances in underwater exploration and genetic taxonomy, scientists have realized that known jellyfish diversity represents only a fraction of what exists. Over the last two decades, more than three hundred new species have been described, highlighting how little of the ocean’s biodiversity we truly understand.

One of the most enigmatic discoveries is Deepstaria enigmatica, a jellyfish found at depths exceeding 1,000 meters. It resembles a floating, transparent cloak capable of enveloping prey. Its body is entirely colorless and almost invisible—a masterpiece of evolutionary adaptation to the deep sea.

In 2018, researchers in the Caribbean identified Tamoya ohboya, humorously named after divers’ startled reaction (“Oh boy!”). Its vivid orange hue and powerful neurotoxic venom make it both deadly and scientifically fascinating.

Equally intriguing are the recently discovered box jellyfish with complex eyes. In tropical Australian and Indonesian waters, several species were found to possess 24 eyes, including lens-based structures that can detect shapes and motion. Some experiments even suggest they can learn and remember obstacles—an extraordinary trait for creatures without central nervous systems.

Thanks to Remotely Operated Vehicles (ROVs), deep-sea expeditions have also uncovered numerous bioluminescent species, glowing in shades of blue, green, and violet. These light displays serve for hunting, camouflage, and communication.

Below is a table summarizing some of the most remarkable recent discoveries:

These discoveries expand not only our understanding of biodiversity but also raise concerns about the fragility of marine ecosystems. Many newly discovered species inhabit regions affected by melting ice, pollution, and underwater noise. Their survival may be short-lived unless conservation measures are taken.

Scientists estimate that nearly 80% of the ocean remains unexplored, implying that countless species—perhaps hundreds of jellyfish—await discovery. Because jellyfish are sensitive to environmental changes, they serve as critical bioindicators of climate shifts, species migrations, and ocean chemistry.

Jellyfish as Symbols of the Future Ocean

Modern ecologists increasingly regard jellyfish as indicators of global change. Their mass blooms across many regions signal ecological imbalance. Rising ocean temperatures, eutrophication, and the decline of predators like tuna and sea turtles create conditions that favor jellyfish proliferation.

In 2009, the Sea of Japan experienced a massive invasion of giant Nemopilema nomurai, each weighing up to 200 kilograms. The bloom destroyed fishing nets, reduced catches, and caused millions in economic losses. Scientists linked the event to ocean current shifts and overfishing of natural predators.

Yet jellyfish also represent resilience and adaptation. Their energy-efficient movement has inspired engineers to design soft-bodied “jellyfish robots” that monitor pollution, track marine life, and even collect microplastics. These innovations show how ancient life forms continue to shape modern technology.

Culturally, jellyfish symbolize fluidity, transformation, and nature’s quiet power. Their apparent fragility conceals remarkable endurance—honed by millions of years of evolution. In this way, jellyfish remind us that adaptability, not dominance, ensures survival.

As climate change reshapes the oceans, jellyfish stand as both a warning and a guide: the first to sense imbalance, yet the last to disappear.

Conclusion

Jellyfish embody one of nature’s greatest paradoxes. Though among the simplest creatures on Earth, they possess intricate survival mechanisms and profound ecological significance. Their story is a living chronicle of evolution that began long before humankind appeared.

The discovery of new species, the study of their bioluminescence, toxins, and regenerative abilities, all open vast new fields in biology, medicine, and technology. Yet perhaps the most valuable lesson jellyfish teach us is about balance and resilience—the art of surviving change without losing harmony.

They have endured global extinctions, adapted to every sea on Earth, and continue to drift gracefully through the depths like ancient keepers of the planet’s memory. Watching their gentle glow in the water, we are reminded that if such simple beings have a future, perhaps humanity does too.