Monterey Bay Aquarium Research Institute

The bumpy jelly stings with their whole body, no tentacles necessary 🪼✨

This jelly launched decades of discovery at MBARI. Researchers first encountered the bumpy jelly (Stellamedusa ventana) in 1990 while exploring Monterey Bay with the remotely operated vehicle Ventana.

The lack of tentacles immediately caught our attention. Most jellies trail long, fine tentacles to stun prey, but the bumpy jelly is covered in tiny bumps loaded with stinging cells. Stellamedusa can capture prey across their entire surface. As they swim, those stinging cells immobilize plankton in their path. Four lacy mouth-arms then sweep the bell's edge to collect the catch—a hunting strategy known in only a small number of deep-sea jellies.

MBARI's growing fleet of autonomous robots, equipped with advanced imaging systems, gives us a persistent presence in the twilight waters Stellamedusa calls home. Long-term studies have revealed that the bumpy jelly is far more common than we first thought, sometimes appearing in blooms deep underwater. Instead of sporadic snapshots, we now have a fuller picture of life in the twilight zone, a reminder of how much more there is to learn as ocean exploration technology advances.

Midweek moment of zen brought to you by a giant phantom jelly. 〰️⁠⁠

The bell of this astonishing jelly is more than one meter (3.3 feet) across and trails four ribbon-like oral (or mouth) arms that can grow to more than 10 meters (33 feet) in length. MBARI’s ROVs have logged thousands of dives, yet we have only seen this spectacular species nine times.⁠ ⁠ The first specimen of the giant phantom jelly was collected in 1899, but it was not until 60 years later that scientists recognized this as a new species. Even now, scientists still know very little about this animal.⁠ ⁠ MBARI’s observations of Stygiomedusa gigantea have helped illuminate its ecological role in the ocean’s depths. During an expedition to the Gulf of California, MBARI’s ROV Tiburon recorded a fish—the pelagic brotula (Thalassobathia pelagica)—alongside a giant phantom jelly. Researchers watched the brotula hover above the bell of its host and swim in and out of the jelly’s voluminous oral arms. The wide-open waters of the midnight zone offer little shelter, so many creatures find refuge among the gelatinous animals that are abundant in this environment.

In the deep sea, we know all about romance. ⁠❤️⁠

A little deep-sea wonder for your Friday 💙✨️

Home is where your crinoid is 💜⭐

MBARI researchers were delighted to spot this purple goiter sponge and its resident crinoid during an expedition to the Taney Seamounts, a chain of ancient underwater volcanoes west of Monterey Bay. The Taney Seamounts formed about 26 million years ago near a mid-ocean ridge. They have thick deposits of fragmental volcanic debris on the flanks and very large, overlapping calderas, evidence of repeated explosive eruptions and caldera collapse.⁠

Mapping one of the ocean’s most extraordinary neighborhoods 🌊

Earlier this month, Principal Engineer Dave Caress led a 10-day expedition aboard MBARI’s flagship research vessel David Packard to conduct high-resolution seafloor surveys with the remotely operated vehicle Doc Ricketts and the Low-Altitude Survey System developed by MBARI engineers. Combining sonar, lidar, stereo photography, and next-generation navigation technologies, this innovative sensor suite enabled the team to capture high-resolution, centimeter-scale maps of Octopus Garden—an octopus nursery near Davidson Seamount—and other deep-sea habitats.

These detailed surveys will help researchers monitor changes over time, better understand how geology shapes deep-sea ecosystems, and guide future expeditions exploring one of the ocean’s most remarkable biological hotspots.

This recent expedition aboard our state-of-the-art flagship vessel highlights MBARI’s expanded capacity for ocean exploration, enabling us to deploy innovative technologies to answer fundamental questions about marine life and ecosystems to help resource managers and policymakers protect unique communities of life thriving deep underwater. Learn more on our website.

#tfw you're trying really hard to hide from Monday 😶‍🌫️

Feather stars are part of an ancient group of echinoderms called crinoids. They're distant relatives of the sea stars and sea urchins you might find in coastal tide pools. Feather stars cling to rocks, corals, and sponges with claw-like appendages called cirri.

Those same rocky habitats provide shelter for plenty of other deep-sea animals. Basket stars (Gorgonocephalus eucnemis) perch high above the seafloor, stretching out their branched arms to catch zooplankton and other drifting food.

Who knew predators could be this pretty? 🩷✨⁠

Just out for a little glide 〰️

Skates are close relatives of sharks and rays that use their broad, wing-like pectoral fins to glide effortlessly across the seafloor. They are found in a variety of ocean habitats around the world.

While we know a lot about the skates that dwell in shallow coastal waters, we know relatively little about those that call the ocean’s inky depths their home. Observations from our advanced underwater robots have provided valuable information about deep-dwelling skates. Video recorded by our robotic submersibles is cataloged with detailed environmental data.

This roughtail skate (Bathyraja trachura) is especially tolerant of low-oxygen environments. While other skates may occasionally visit these oxygen-starved waters, this is the only species that can stay there consistently.

Floating through inner space ✨️

This species of jellyfish, Poralia rufescens, is one that most people will never see. It lives thousands of meters beneath the ocean's surface, often drifting just above the seafloor.

The deep sea is full of friend-shaped surprises. ❤️🤗

Last month, our researchers spent 10 days exploring the midnight zone, documenting everything from glowing jellyfish and siphonophores to colorful crustaceans like this little ocean buddy. This tiny treasure is a mysid shrimp in the genus Gnathophausia. They are typically found in the midwater and feed on smaller crustaceans.

MBARI researchers have developed innovative new technology for studying the seafloor 💡🌊🤖

MBARI researchers are transforming our understanding of the processes that shape the seafloor. Since the beginning of 2025, a team of MBARI scientists and engineers has been testing Geo-Sense, a new portable instrument that uses distributed acoustic sensing technology for long-term, high-resolution seafloor monitoring. 

Geo-Sense measures the tiny strains and vibrations on a fiber-optic cable laid on the seafloor to track a wide range of processes, from underwater landslides to earthquakes. MBARI researchers recently published a detailed description of this innovative instrument in the journal Scientific Reports, highlighting the remarkable collaboration and expertise that brought it to life.

We sat down with Senior Scientist Aaron Micallef, a marine geologist who leads MBARI’s Seafloor Processes Team, to learn more about this groundbreaking instrument and the data being collected. Learn more on our website.

A technicolor feast in the deep 💜🍴🩷⁠

Seafloor snacking with a spectacular crustacean 🦀

Meet one of the ocean's biggest surprises. 🌊

Big red jellies can reach more than a meter (three feet) across. These jellies are covered in tiny, harpoon-like stinging cells that stun prey. Unlike most jellyfish, big red doesn't have long trailing tentacles. Instead, a cluster of finger-like oral arms beneath its bell helps it capture food.

Big red was first discovered off the central California coast in 1988, by MBARI staff. This jelly has been spotted across the Pacific Ocean, from Baja California to Hawaii to Japan.

Deep-sea jellies, siphonophores, and more: MBARI's Southern California expedition 🌊🪼💫

From graceful jellies and sleek siphonophores to dazzling comb jellies and dancing worms, MBARI researchers are revealing the hidden diversity of delicate drifters in the deep. Our Biodiversity and Biooptics Team, led by Senior Scientist Steven Haddock, recently concluded a 10-day expedition from Monterey Bay to the Channel Islands aboard MBARI’s flagship research vessel David Packard to study the biogeography and physiology of gelatinous plankton. 

Using MBARI’s remotely operated vehicle (ROV) Doc Ricketts, they observed and collected gelatinous plankton deep underwater in the ocean’s midnight zone. A specialized low-light camera developed by MBARI scientists and engineers allowed the team to record the remarkable bioluminescence displays of these deep-sea jellies in their natural habitat. They logged observations of several undescribed ctenophores, a new species of Erenna siphonophore with elaborate lures, and a siphonophore they had previously only seen in the waters of the Gulf of California, advancing efforts to catalog life in the deep ocean.

Blending in like a pro 🐙😶‍🌫️

This red octopus (Octopus rubescens) blends seamlessly into the sandy seafloor, patiently waiting for its next meal to wander by. Like other octopuses, it can rapidly change both its color and skin texture to match its surroundings, making it remarkably difficult to spot.