The sea is often associated with mystery - after all, who knows what lurks in the occluded depths? Take a look at...
The Maw of the Pelican EelFound swimming beneath the temperate and tropical waters of all the oceans, the pelican or gulper eel resembles something from a sci-fi horror film. Initially resembling an elongated slender black fish, the pelican eel has a massive set of jaws that cover around a quarter of the length of the body. The eel unfolds its massive maw to feed, drawing in seawater and inflating until it resembles a tadpole. The water is vented through the gills, straining out any crustacean or invertebrate prey to be swallowed.
To cap off the alien appearance of this malleable creature, it possesses a bioluminescent tip on the tail. This emits a pulsing red glow - presumably to draw the attention of potential prey.
The worm manufactures these fangs by producing the amino acid dihydroxyphenylalanine (DOPA) and combining it with copper-rich sediment from the seafloor. The copper acts as a catalyst to transform the DOPA into melanin, and the resulting melanin-copper slurry is used to form vicious metal teeth.
The bloodworm attacks prey by ambush, burrowing beneath the sand and then inverting its digestive system, combining both stomach and copper fangs into a biological harpoon. On contact, the fangs clamp down on prey and inject a cocktail of venoms that paralyze the victim and allow the worm to devour it alive.
The sharks are thought to have developed their "fin-walking" talents from their preferred habitat of rockpools and reefs, where marine creatures can easily become cut off as the tide withdraws and leaves rockpools. These sharks are happy enough to maneuver underwater by "walking" on the seafloor, but the ability to hop from one pool to another can help them avoid predators, find new prey or escape a drying or deoxygenating pool.
The Attack of the Giant IsopodIsopods are crustaceans with segmented bodies, two sets of antennae and seven pairs of limbs. They can be found on land or in fresh or salt water, and the most obvious example is the woodlouse. Far more impressive is Bathynomus yucatanensis, a new discovery found in the deep waters off the coast of the Yucatán Peninsula in Mexico, an isopod that can reach 26cm in length.
This particular isopod was found in a baited trap at a depth between 600 to 800 meters in 2017, before being held at Enoshima Aquarium in Japan having been misidentified as another giant isopod Bathynomus giganteus. Despite their size, these creatures are scavengers and largely harmless.
The worms build tube-like homes on the sides of "smokers" that expel boiling acidic water and clouds of mineral ash. The worms lives in these conditions by moving between the boiling & nutrient rich water at the hot end of the tube, and the cool ocean water of the cold end. The worms survive these forays thanks to a coat of bacteria that insulate them from the temperature.
Interestingly the back-and-forth movement of the worm inside the tube serves to "pump" cool water into the tube. Not only does this make the tube more habitable for the worm, it also helps cool the bacterial gel that coats the sides of each smoker and makes it easier for other life to flourish near the vent.
The Grasp of the AnemoneIf you picture an anemone, you probably imagine a small-ish blob of colorful jelly-like tissue surmounted by stinging tentacles. Not all anemones are constrained to these small sizes though - the giant plumose anemone can reach up to a meter in height, filtering small prey out of the water.
It seems the giant plumose anemone is not a picky eater - scientists performed "DNA metabarcoding" on the gut contents of 12 unfortunate anemones, finding everything from plankton to ant and even spider DNA. This suggests that the anemone can "catch" insects and arachnids that fall into the ocean. A decent haul of unidentified DNA was also present, indicating that there is still more life to find in the depths!
Another unfair advantage possessed by Malacosteus fish is an ability to detect red light - most deep sea creatures can only see shades of blue, as red light cannot penetrate far into the depths. They use this ability in conjunction with red bioluminescence to produce a "search beam" that few other fish can see.
The smaller right eye is kept facing downwards to look for flashes of bioluminescence in the inky depths, indicating potential predators or prey. Meanwhile the larger left eye is held upwards, scanning the dimly lit water for shadows of creatures swimming above it, even if they try to blend in to the ambient filtering sunlight with camouflage or a bioluminescent underbelly.
- The Maw of the Pelican Eel
- The Hunger of the Bloodworm
- The Walking Shark
- The Attack of the Giant Isopod
- The Lair of the Pompeii Worm
- The Grasp of the Anemone
- The Fish With Bear-Trap Jaws
- The Evil-Eyed Squid
 |
| Ocean-dwellers can be much stranger than the average fish... (Alex Rose) |
The Maw of the Pelican EelFound swimming beneath the temperate and tropical waters of all the oceans, the pelican or gulper eel resembles something from a sci-fi horror film. Initially resembling an elongated slender black fish, the pelican eel has a massive set of jaws that cover around a quarter of the length of the body. The eel unfolds its massive maw to feed, drawing in seawater and inflating until it resembles a tadpole. The water is vented through the gills, straining out any crustacean or invertebrate prey to be swallowed.
To cap off the alien appearance of this malleable creature, it possesses a bioluminescent tip on the tail. This emits a pulsing red glow - presumably to draw the attention of potential prey.
The Hunger of the Bloodworm
You might be skeptical if someone told you a worm with fangs made of metal and a payload of 32 different toxins lives beneath the waves. The bloodworm is exactly that however - it extracts copper from marine sediment to form a set of metal "teeth" that last throughout its five year life span.The worm manufactures these fangs by producing the amino acid dihydroxyphenylalanine (DOPA) and combining it with copper-rich sediment from the seafloor. The copper acts as a catalyst to transform the DOPA into melanin, and the resulting melanin-copper slurry is used to form vicious metal teeth.
The bloodworm attacks prey by ambush, burrowing beneath the sand and then inverting its digestive system, combining both stomach and copper fangs into a biological harpoon. On contact, the fangs clamp down on prey and inject a cocktail of venoms that paralyze the victim and allow the worm to devour it alive.
The Walking Shark
Sharks are known as the archetypal marine predator, so it may seem somewhat unsporting that some can walk on land. The epaulette shark found on the Great Barrier Reef seems to have developed this skill in response to its changing environment, and can make short trips of up to 90 feet on land, while surviving oxygen deficiency for around 2 hours.The sharks are thought to have developed their "fin-walking" talents from their preferred habitat of rockpools and reefs, where marine creatures can easily become cut off as the tide withdraws and leaves rockpools. These sharks are happy enough to maneuver underwater by "walking" on the seafloor, but the ability to hop from one pool to another can help them avoid predators, find new prey or escape a drying or deoxygenating pool.
 |
| Deep sea isopods grow a great deal larger than a woodlouse... (Joshua Manjgo) |
The Attack of the Giant IsopodIsopods are crustaceans with segmented bodies, two sets of antennae and seven pairs of limbs. They can be found on land or in fresh or salt water, and the most obvious example is the woodlouse. Far more impressive is Bathynomus yucatanensis, a new discovery found in the deep waters off the coast of the Yucatán Peninsula in Mexico, an isopod that can reach 26cm in length.
This particular isopod was found in a baited trap at a depth between 600 to 800 meters in 2017, before being held at Enoshima Aquarium in Japan having been misidentified as another giant isopod Bathynomus giganteus. Despite their size, these creatures are scavengers and largely harmless.
The Lair of the Pompeii Worm
Perhaps the most heat tolerant animal ever discovered, the Pompeii worm makes a home in the boiling waters surrounding hydrothermal vents.The worms build tube-like homes on the sides of "smokers" that expel boiling acidic water and clouds of mineral ash. The worms lives in these conditions by moving between the boiling & nutrient rich water at the hot end of the tube, and the cool ocean water of the cold end. The worms survive these forays thanks to a coat of bacteria that insulate them from the temperature.
Interestingly the back-and-forth movement of the worm inside the tube serves to "pump" cool water into the tube. Not only does this make the tube more habitable for the worm, it also helps cool the bacterial gel that coats the sides of each smoker and makes it easier for other life to flourish near the vent.
 |
| Some sea anemones can reach a meter in height... (Praveen Kenderla) |
The Grasp of the AnemoneIf you picture an anemone, you probably imagine a small-ish blob of colorful jelly-like tissue surmounted by stinging tentacles. Not all anemones are constrained to these small sizes though - the giant plumose anemone can reach up to a meter in height, filtering small prey out of the water.
It seems the giant plumose anemone is not a picky eater - scientists performed "DNA metabarcoding" on the gut contents of 12 unfortunate anemones, finding everything from plankton to ant and even spider DNA. This suggests that the anemone can "catch" insects and arachnids that fall into the ocean. A decent haul of unidentified DNA was also present, indicating that there is still more life to find in the depths!
The Fish With Bear-Trap Jaws
The deep sea is home to many strange fish, but the loosejaws have to be one of the weirdest. They take their name from an exposed jaw that extends beyond the skull. They lack a intermandibular membrane (i.e. they have no flesh between the bones of the lower jaw) meaning that they can slam their mouths shut without battling water resistance. The overall effect resembles a bear-trap clamping down on a victim.Another unfair advantage possessed by Malacosteus fish is an ability to detect red light - most deep sea creatures can only see shades of blue, as red light cannot penetrate far into the depths. They use this ability in conjunction with red bioluminescence to produce a "search beam" that few other fish can see.
The Evil-Eyed Squid
Like something out of surreal artwork, the cockeyed squid has two radically different eyes. This allows the squid to have a perfect tool for searching the water no matter the depth - even if it does make them look strange.The smaller right eye is kept facing downwards to look for flashes of bioluminescence in the inky depths, indicating potential predators or prey. Meanwhile the larger left eye is held upwards, scanning the dimly lit water for shadows of creatures swimming above it, even if they try to blend in to the ambient filtering sunlight with camouflage or a bioluminescent underbelly.
Thanks for reading - you might also like...