Meet the Siphonophores
Even with the same basic blueprint, the diversity of siphonophores is spectacular. Dive in with MBARI and explore their breathtaking beauty
Swimming bells of angler siphonophore, Erenna sirena (2003) by MBARIMonterey Bay Aquarium Research Institute
Siphonophores (pronounced “sigh-fawn-oh-fours”) are colonial creatures made up of specialized segments that work together as one. They may not be familiar to most, but they’re abundant animals in the ocean. In fact, siphonophores are some of the most important predators in ocean ecosystems.
Central stem of a siphonophore, Apolemia sp. (2004) by MBARIMonterey Bay Aquarium Research Institute
Scientists have described some 175 siphonophore species. Most follow a similar body plan—a gas-filled float provides buoyancy, swimming bells propel the colony, and a central stem bears specialized parts for feeding, defense, and reproduction.
Crystal siphonophore, Frillagalma vityazi (2006) by MBARIMonterey Bay Aquarium Research Institute
From the surface to the seafloor, the ocean is home to many extraordinary siphonophores. Meet some of the most stunning species MBARI and our collaborators have encountered.
Portuguese man o’ war
On the surface, you might think a Portuguese man o’ war is a jelly. Its long, trailing tentacles deliver a potent sting. But this animal is actually a siphonophore, using that balloon-like bladder and thin “sail” to ride winds and waves at the ocean’s surface.
Physalia physalis
Range: worldwide in tropical waters
Depth: surface
Size: float to 30 centimeters (12 inches) long, tentacles to 10 meters (33 feet) long
Diet: small fishes
Hula skirt siphonophore
A small gas-filled float keeps this siphonophore upright while it searches for a meal. As it pulses those swimming bells, it twirls that “skirt” and beaded tentacles to snag morsels of food.
Physophora hydrostatica
Range: worldwide in temperate waters
Depth: surface to 400 meters (1,300 feet)
Size: 40 centimeters (16 inches)
Diet: plankton, crustaceans, and small fishes
Common siphonophore
This little siphonophore has a big impact on deep-sea food webs. It’s one of the principal predators on krill and is abundant in the midwater. It follows the nightly migration of its shrimp-like prey—it dwells in deeper water during the day and swims to the surface at nightfall.
Nanomia bijuga
Range: worldwide
Depth: surface to 700 meters (2,300 feet)
Size: 30 centimeters (12 inches)
Diet: plankton, especially krill
Rocket ship siphonophore
This tiny siphonophore jets through the water with quick contractions of its pointy swimming bells. It darts here and there. Once it has found the perfect spot to hunt, it sets out fine tentacles to trap prey.
Lensia conoidea
Range: worldwide
Depth: surface to 500 meters (330 to 3,900 feet)
Size: 4 centimeters (about 1.5 inches)
Diet: small crustaceans
Giant siphonophore
Giants dwell in the deep sea. In the still waters deep beneath the surface, this siphonophore can grow longer than a blue whale. Rough currents sometimes break up the animal and bring bits of it to shallower waters.
Praya dubia
Range: worldwide
Depth: surface to 600 meters (2,000 feet)
Size: 40 meters (130 feet)
Diet: small crustaceans and jellies
Clown siphonophore
Siphonophores are important predators in the ocean. As they drift in open water, they spread their elaborate tentacles out to tempt unsuspecting prey. At the slightest touch, the tentacle rapidly recoils to snare a meal.
Lychnagalma utricularia
Range: Pacific and Atlantic Oceans, Mediterranean Sea
Depth: 100 to 700 meters (330 to 2,300 feet)
Size: 20 centimeters (8 inches)
Diet: large crustaceans
Thorny siphonophore
Siphonophores come in all sorts of shapes and sizes. This thorny siphonophore has a series of serrated swimming bells. But those spikes probably don’t offer much protection. A transparent body and potent stinging cells are much more effective deterrents for predators.
Vogtia serrata
Range: worldwide
Depth: 200 to 1,500 meters (660 to 4,900 feet)
Size: 8 centimeters (3 inches)
Diet: plankton, crustaceans, and small fishes
Knobby siphonophore, Halistemma rubrum (2015-01-14) by Monterey Bay Aquarium Research Institute (MBARI)Monterey Bay Aquarium Research Institute
Knobby siphonophore
Many siphonophores have expansive ranges. This species lives in warm waters worldwide. Because most dwell in deeper water, they remain out of sight compared to their relatives, jellies, that can be abundant near the surface.
Halistemma rubrum
Range: Pacific, Indian, and Atlantic Oceans and Mediterranean Sea
Depth: surface to 300 meters (1,000 feet)
Size: 1 meter (about 3 feet)
Diet: large crustaceans
Red siphonophore, Stephanomia amphytridis (2015-01-14) by Monterey Bay Aquarium Research Institute (MBARI)Monterey Bay Aquarium Research Institute
Royal siphonophore
Most of what we know about siphonophores comes from the broken bits and pieces of animals naturalists collected 200 years ago. Now underwater video helps scientists learn more about these amazing animals.
Stephanomia amphytridis
Range: worldwide
Depth: 500 to 2,000 meters (1,600 to 6,600 feet)
Size: 10 meters (30 feet)
Diet: small fishes
Crystal siphonophore
Many siphonophores produce bioluminescence. This “living light” likely offers protection from predators. In the dark depths, a burst of blue light disorients or distracts so the siphonophore can swim to safety.
Frillagalma vityazi
Range: worldwide
Depth: 200 to 700 meters (660 to 2,300 feet)
Size: 4 centimeters (almost 2 inches)
Diet: plankton, crustaceans, and small fishes
Lightbulb siphonophore
MBARI researchers are studying how siphonophores and other deep-sea animals make light. We’re also working to understand the purpose of these dazzling displays.
Rosacea sp.
Range: worldwide, except for polar waters
Depth: surface to 800 meters (2,600 feet)
Size: 2 meters (6.5 feet)
Diet: small crustaceans
Weird and Wonderful: The fish-eating siphonophore Erenna (2019-03-08) by Monterey Bay Aquarium Research Institute (MBARI)Monterey Bay Aquarium Research Institute
Angler siphonophore
This siphonophore is a cunning predator. It dangles luminescent lures to hunt for prey. Its tentacles have glowing red tips that mimic crimson crustaceans. Unsuspecting fishes that get too close become a feast. Learn more about the angler siphonophore.
Erenna sirena
Range: central California to Baja California
Depth: 1,600 to 2,400 meters (5,200 to 7,900 feet)
Size: 45 centimeters (18 inches)
Diet: small fishes
Green caterpillar siphonophore
Fluorescent proteins give this siphonophore its vivid appearance. In the ocean’s twilight zone, those proteins absorb the ambient blue light and then glow green. We’re still not sure what function fluorescence serves.
Lilyopsis fluoracantha
Range: only known from Monterey Bay
Depth: 100 to 500 meters (330 to 1,600 feet)
Size: 12 centimeters (about 5 inches)
Diet: crustaceans
Weird and Wonderful: This spectacular deep-sea siphonophore is a sight to see by Monterey Bay Aquarium Research Institute (MBARI)Monterey Bay Aquarium Research Institute
Red siphonophore
MBARI researchers and our collaborators have seen a rainbow of siphonophores in the depths of Monterey Bay and beyond. This is just one of the 22 new siphonophore species we've discovered in the deep sea. Learn more about the red siphonophore.
Marrus claudanielis
Range: known from northeastern Pacific Ocean and northwestern Atlantic Ocean, but may be more widespread
Depth: 500 to 1,500 meters (1,600 to 4,900 feet)
Size: 30 centimeters (12 inches)
Diet: large crustaceans
Spaghetti siphonophore
Meet one of the most unique siphonophores. This species doesn’t have any swimming bells. Instead, it drifts on the currents with a buoyant float. Its twisted and tangled body bobs just above the seafloor. Those elaborate elastic tentacles snag small fishes and other prey
Bathyphysa conifera
Range: Pacific and Atlantic Oceans
Depth: 200 to 4,000 meters (660 to 13,100 feet)
Size: 2 meters (6.5 feet)
Diet: small crustaceans and fishes
Balloon siphonophore
The waters just above the seafloor are rich with food. But swift currents could sweep away this little siphonophore. Its solution? Long, sticky tentacles anchor it in place as other tiny tentacles grab for food.
Stephalia dilata
Range: eastern Pacific Ocean
Depth: 1,700 to 2,800 meters (5,600 to 9,200 feet)
Size: 5 centimeters (about 2 inches) across
Diet: plankton and other drifting particles
Leafy siphonophore, Bargmannia amoena (2002) by MBARIMonterey Bay Aquarium Research Institute
We’re revealing the ocean’s delicate drifters
Robotic submersibles give researchers at MBARI the opportunity to observe life in the midnight zone. Siphonophores and their more distant relatives, jellies and comb jellies, thrive in this world without physical boundaries. Back in the lab, we’re working to understand aspects of their biology in greater detail—from how they build their bodies to how they produce their stunning luminescence.
