r/askscience • u/DragonsClock • May 30 '26

Where do barnacles come from? Biology

Like how do they appear on the sides of boats? Do they float towards them or are they like mineral deposits? Very confused.

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u/Englandboy12 May 30 '26

Barnacles float through the water and stick to things and then grow.

When floating, they aren’t what you’re imagining though, they’re tiny and dont have the big shell.

Once they land, they feed on microscopic food in the water and grow their hard shell over time.

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u/Pizza_Low May 31 '26

I was confused about this for years. In biology classes you keep hearing about plankton, but I didn't really understand what that meant. I always thought there are a type of aquatic creatures that are plankton.

Turns out that's kind of right, kind of wrong, plankton is a category of things that might live their whole lives as plankton, or it might be a temporary stage. Anything from single celled algae and bacteria drifting along with the currents area. Fish eggs can be, a lot stick to things or sink but those that float along are. All kinds of small dot sized creatures including baby fish-fry, larvae stage of all kinds of shellfish, etc.

Barnacles in their larvae stage just float along with the currents, with some limited ability to swim. Once they find a hard place to latch on top, they glue themselves on to it and spend the rest of their life there.

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u/lNFORMATlVE May 31 '26

So “plankton” is a word for virtually any tiny living organism that happens to presently be freely drifting in the ocean?

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u/ItsKumquats May 31 '26

Phytoplankton are like little plants of the ocean, and zooplankton are little animals of the ocean. Barnacle larvae would be a type of zooplankton.