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This is Scientific American’s 60-Second Science. I’m Steve Mirsky. Got a minute?

A rolling stone gathers no moss¹. But a salamander embryo² can attract algae³ inside its tissues and cells. This intimate co-habitation—the first ever seen between algae and a vertebrate—is revealed in the Proceedings⁴ of the National Academy of Sciences.

Spotted⁵ salamanders lay their eggs in pools in spring. And the egg capsules actually look green, thanks to the algae that surrounds the resident embryos⁶. That relationship benefits both parties. Algae feed on the nitrogen-rich waste products generated by the embryos. And the embryos bask⁷ in the oxygen given off by the algae. Take away their algae, and spotted salamander babies hatch smaller and less mature.

So that’s the eggs. But this study is the first to show that the algae actually inhabit the embryo itself. Using imaging techniques and DNA⁸ testing, scientists found algae inside the cells of young salamander embryos—and even in the reproductive tracts⁹ of some adult females, which suggests that some algae may be handed down directly from parent to child, more evidence that many individuals are really entire little ecosystems¹⁰.

Thanks for the minute. For Scientific American’s 60-Second Science, I’m Steve Mirsky.