Science & Environment
1:49 pm
Mon March 24, 2014

Three Ways to Learn More about the Eco-History of Guano

The depletion of Peru's guano islands lay at the heart of the War of the Pacific.
The depletion of Peru's guano islands lay at the heart of the War of the Pacific.
Credit Wikimedia Commons

It enabled the industrialization of agriculture, led to the discovery of El Nino, helped spawn the modern environmental movement, and lay at the heart of the War of the Pacific. What is it?

Guano, the excrement of South American seabirds.

Guano isn't just any bird poop. (Actually, the word has come to refer to feces of any flying animal, including bats.) Along with mineral nitrates found in the Atacama Desert, the South American seabird variety of guano is the richest source of nitrogen on the planet.

The oceanography and climate of the Pacific coast of Chile and Peru combine to create an incredibly rich environment for marine fish and the sea birds who eat them. They, in turn, produce copious quantities of guano, rich in nitrate, phosphate, and potassium - the three major components of fertilizers that any gardener will recognize. And because there's very little rain, that nutrient wealth stays put, doesn't wash away.

Guano fertilizer revolutionized 19th century farming and left an indelible mark on economics and politics in South America, and beyond. Here's how you can learn more:

1. If your budget (both time and money) allows, there's Gregory Cushman's comprehensive eco-history, Guano and the Opening of the Pacific World: A Global Ecological History. After reading it, you'll wonder how we ever overlooked the importance of quano. But be forewarned: the book is mammoth, with a price tag to match. (Note: this recently came out in paperback at a much more reasonable price.)

2. Gregory Cushman and I hit on some of the major themes and highlights - from an ancient Peruvian creation myth about guano, to the Golden Age of Guano, and the demise of the industry in the 20th century. You can listen to our conversation:

3. Before it was an international hub of scientific research, Woods Hole, MA was a whaling, fishing, and - you guessed it - guano port. For a really quick hit that ties the guano trade into local maritime history:

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