Marine worm with pink curly parapodia

All photos: Alexander Semenov

Marine zoologist and photographer Alex Semenov has a talent for capturing extraordinary portraits of underwater life, and he doesn't disappoint with his latest collection documenting the wonderful (and strange) world of polychaetes!

Sometimes referred to as "bristle worms," polychaetes are a robust, diverse class of predominantly marine annelids that live in all depths of the Earth's oceans. These organisms have been found everywhere — plankton-rich surface waters, hydrothermal vents, the cold, desolate abyssal plain and even in the darkest depths of the Mariana Trench.

While they might make some folks squirm, it's hard to deny the beauty of the worms' unique patterns and coloration, which are often accompanied by iridescence or even luminescence. Perhaps even more stunning are the fleshy, intricate protrusions — called parapodia — that extend from their segmented bodies.

Semenov captured half of these photos at the Lizard Island Research Station near Australia's Great Barrier Reef, where he was attending a two-week conference on polychaetes. The other half were taken at Russia's White Sea Biological Station, where Semenov serves as head of the diving team.

Although more than 10,000 polychaete species have been described, scientists speculate there are many species that remain undiscovered. Thanks to Semenov's recent photographs, 222 different worm species are now being studied and documented by scientists.

Scroll down for more amazing marine images, and be sure to follow Semenov on Facebook and Flickr for future updates.

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Blue and yellow marine worm with egg-like sac
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Orange marine worm with purple parapodia
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Purple transluscent marine worm
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Green marine worm with striped parapodia
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Purple and orange marine worm
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Bundled up marine worm
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Marine worm with feathery parapodia
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Iridescent marine worm
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Transluscent marine worm
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Pink marine worm
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Creepy green marine worm
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Catie Leary is a photo editor at Mother Nature Network. Follow her on Twitter and Google+.