The scientific team aboard the R/V Western Flyer this week is focused on learning more about the gelatinous creatures that inhabit the open midwaters of the ocean. This is the largest, and yet least understood, habitat on our planet. Most of the researchers are specifically studying ctenophores or siphonophores, or both. In today’s report we’ll focus on the ctenophores.

Ctenophores, or comb jellies, are characterized by having eight rows of cilia which are primarily used for locomotion. Comb jellies don’t sting, but have sticky tentacles for capturing prey. They eat crustaceans and other small zooplankton, although some species prefer to eat other ctenophores! Other predators of comb jellies include jellyfish, sea turtles, and fish. They are transparent and often colorless, however when light diffracts off the comb rows it creates striking rainbow patterns. Many also exhibit brilliant bioluminescent displays when disturbed. The research team is taking a closer look at these bioluminescent properties, as well as, making progress toward a worldwide ctenophore survey. Ctenophores are extremely delicate and we are learning a lot more about them by using ROV cameras and advance collection methods than we ever could in the past by using net trawls.

Ctenophores can be found in marine environments, from the poles to the tropics, and from the surface to the deepest parts of the ocean, yet very little is known about how they have evolved to survive such a wide range in temperature, oxygen, light, and pressure. That is another part of what the team is working to uncover. To do this, the researchers are using a variety of new tools and techniques including high-pressure instruments, optical oxygen microsensors, genome-scale sequencing, protein purification, and gene cloning and expression in the lab. The greater challenge is how to also conduct experiments in the animal’s natural environment.

For more information see:

Ctenophores: the story of evolution in the oceans

How comb jellies adapted to life in the deep sea