Science

Guano in 60 Seconds

A quick introduction to the surprising ecological benefits of bird droppings.
  • Few things are as good for an island as bird droppings. Guano is full of essential nitrogen—the stuff in fertilizer that...
    Artwork by Alicia Cocchi
    01
  • That nitrogenrich guano also washes into the sea where it nourishes reefs.
    Artwork by Alicia Cocchi
    02
  • But few things are as bad for an island as invasive rats which show up and devour everything in their path. When the...
    Artwork by Alicia Cocchi
    03
  • Scientists examined 12 islands in the Indian Ocean's Chagos Archipelago—six ratfree six ratinfested—and were able to...
    Artwork by Alicia Cocchi
    04
  • The key is nitrogen. Seabirds that populate these islands forage on the open ocean for small fish like sardines which...
    Artwork by Alicia Cocchi
    05
  • By tracking that isotope scientists could see how ratravaged seabird populations were changing the islands' nitrogen stores.
    Artwork by Alicia Cocchi
    06
  • Soil samples showed that on islands where rats had not invaded nitrogen input from bird droppings was a staggering 250...
    Artwork by Alicia Cocchi
    07
  • The team also found higher levels of nitrogen in reef algae and fish near ratfree islands.
    Artwork by Alicia Cocchi
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  • The dearth of seabirds—and therefore their nitrogeninfused poop—dramatically affects coral populations.
    Artwork by Alicia Cocchi
    09
  • But the true culprit isn't rats. It's the humans who introduce the pests to the islands in the first place. Thankfully...
    Artwork by Alicia Cocchi
    10
Matt Simon was a senior staff writer covering biology, robotics, and the environment. He’s the author, most recently, of A Poison Like No Other: How Microplastics Corrupted Our Planet and Our Bodies. ... Read More
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TopicsAMP StoriesEcology
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