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Blog Tags: Marine Life Encyclopedia

Marine Monday: Giant Tube Worms

Image via Wikimedia Commons.

When giant tube worms were discovered in the 1970s, they were like nothing that had ever been seen before, and scientists still find them fascinating.

That’s because they live in some of the harshest environments and, unlike almost all kinds of life on Earth, do not rely on the sun for energy. Most life on the planet relies on energy from the sun, mediated by phytoplankton and plants that convert carbon dioxide into sugars. But not in deep-sea vent communities.

Giant tube worms live in the Eastern Pacific Ocean more than a mile underwater. The ocean floor here is geologically quite active, and vents are forming and closing regularly. When a new vent forms, giant tube worms are among the first species to colonize the area, and their population can reach several thousand adult worms in a couple years. The worms form long tubes out of chitin, the same material that makes up the exoskeletons of insects, crabs, and lobsters

Larval worms will float through the ocean until they find an area that is chemically appropriate to settle down in. As larvae, the worms have mouths and digestive tracts, but these are lost once they settle down and develop. Instead, adults have a large sack that holds symbiotic chemosynthetic bacteria. These bacteria oxidize sulfur produced by the vents, providing energy for the worm.

You can learn more about amazing giant tube worms from Oceana’s marine wildlife encyclopedia.

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Marine Monday: Caribbean Reef Octopus

caribbean reef octopus

Unsurprisingly, the Caribbean reef octopus is found throughout the Caribbean, deep within coral reefs. It can grow up to 40 inches long, including its tentacles. As a defense mechanism, it can change color—from blue-green and brown to shimmery red—as well as texture.

Caribbean reef octopuses establish lairs in the reef, which they often disguise with rocks and coral. Although they move their dens regularly, they protect them fiercely. If a strange octopus does not retreat, the defender will sometimes even strangle and eat it.

The same fate awaits unlucky male octopuses who try to mate with uninterested females. If attacked when hunting, the Caribbean reef octopus can pull water into itself, then shoot it out to speed the other way, often also releasing a cloud of ink to confuse predators.

Octopuses hunt at dawn or dusk, which is typical for crustaceans like crabs and shrimp. These cephalopods are fished locally, but not on a large scale, and they are not believed to be at risk of extinction, although they may struggle if the reefs they call home disappear.

Learn more about the Caribbean reef octopus and other fascinating animals at Oceana’s marine life encyclopedia.

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