Researchers have documented several new types of plankton called comb jellies in the Colombian Caribbean and Pacific, including six species never recorded in Colombian waters before.
Ctenophores (comb jellies) are ancient creatures that were on the planet long before the dinosaurs. Despite their name, they aren’t related to jellyfish. Found in oceans all over the world, these gelatinous creatures can be surprisingly pretty – some species seem to shimmer with rainbow patterns that pulse across their bodies.
These twinkling colours are created by eight rows of hair-like appendages called cilia, which throb back and forth to help them move through the water. This causes refraction of the light, which creates the appearance of a kaleidoscope dancing across their bodies.
Comb jellies are incredibly delicate, which makes them very difficult to study. “These fragile organisms dissolve when collected in nets, so they can only be studied through images,” says Juan Mayorga, a National Geographic Pristine Seas marine scientist and one of the authors of the new study documenting 15 ctenophores in Colombian waters.
Some of the data was collected from a 2022 Pristine Seas expedition while others were gathered by citizen scientists.
“The results fill a historical information gap on a key group of gelatinous plankton and demonstrate the value of non-invasive methodologies and explorations in remote areas to strengthen knowledge of marine biodiversity,” says Cristina Cedeño-Posso, the study’s lead author and a researcher at INVEMAR.
Because they couldn’t collect such fragile specimens, the research team observed them in the water and took an array of gorgeous photos. The pictures show the diversity of these ancient animals: some look like alien spaceships, others resemble little water balloons and some trail through the water like shining ribbons.
Although they might look strange to us, comb jellies are a vital part of the oceanic food web.
“Ctenophores are carnivorous, and,” says Smithsonian Ocean on its website. This includes fish eggs, larvae and other small planktonic creatures. Although different types of comb jellies have a range of feeding strategies, they often have something in common: colloblasts.
“Many comb jellies have colloblasts lining their tentacles, which work like nematocysts but release glue instead of venom,” says Smithsonian. “Upon touch, a spiral filament automatically bursts out of colloblast cells that releases the sticky glue. Once an item is stuck, the comb jelly reels in its tentacle and brings the food into its mouth.”
In turn, fish, turtles and crustaceans prey on ctenophores.
“Our team’s photography didn’t just document beauty; it enabled taxonomy and discovery, resulting in six new species records for Colombia,” says Mayorga. “This paper beautifully illustrates what happens when scientific rigour meets the art of underwater photograph.”
In pictures: spectacular comb jellies
Top image: Cestum veneris. Credit: Enric Sala, National Geographic Pristine Seas
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