The Bird Poop Revolution
Guanay Cormorant - Ballestas - Perù. Francesco Veronesi via Wikimedia Commons CC-BY-SA 2.0
It’s the 1800s, and the global population is rapidly expanding thanks to modernisation. Many people, particularly in Europe and the US, are leading longer, healthier lives and not dying in quite such dramatic numbers as before.
But bigger populations need more food, and centuries of increasingly intensive agriculture on limited farmland have begun to deplete the nutrients in many farmers’ fields.
To keep producing enough food to fill all these hungry bellies, they need a way to put nutrients for plants back into the soil and make it more fertile. In other words, they need fertilizers.
Unfortunately, farmers in the 1800s couldn’t just pop down to the garden centre and buy some chemical fertilizer, because that hadn’t been invented yet. Mainly they relied on natural resources like human and animal manure, and techniques such as crop rotation. But these interventions could only do so much.
Then in 1805, the German naturalist and explorer Alexander von Humboldt brought back a strange substance from Peru that the indigenous population had been using to fertilize their fields for hundreds of years. This stuff turned out to be the solidified poop of a seabird called the guanay cormorant, which flocked around Peru’s rocky coastline.
The dry coastal climate meant that the bird’s poop - known as guano - piled up on the shore, together with the empty eggshells and bones of dead birds, hardening into impressive craggy islands rather than being washed away.
If guano could help the Peruvian farmers maintain the fertility of their fields, why couldn’t it do the same for the green and pleasant lands here in Britain?
After a couple of years of successful field trials, William Meyer, a businessman from Liverpool, placed the first large order for this ‘white gold’, and the guano boom began.
This new era of agriculture wasn't quite welcomed by everyone, though. As might be expected from a cargo that’s little more than dried bird excrement, when the guano ships reached English shores, the smell was so bad that the populations of nearby towns fled for the hills to get away from the stench.
But by the mid-1800s, guano was well known as the best fertilizer a farmer could get, and miners came from far and wide to harvest the stuff on the Peruvian shores.
Indentured Chinese labourers guano mining in the Central Chincha Islands off Peru, 1865. Public Domain
The demand for guano was so high that the guanay cormorant was nicknamed the 'billion-dollar bird,' and the US passed laws stating that US citizens could claim remote islands for the country if they harboured the treasured bird poop. Countries even fought wars over access to guano!
Unsurprisingly, scientists became very curious about what made guano so great. Their first observation was that guanay cormorants ate an awful lot of fish. This high protein diet meant that their poop contained a lot of nitrogen, a vital nutrient for plant growth, making it an excellent natural fertilizer.
Next, researchers peered deeper into the poo, bringing forth a flurry of research and papers published in the 19th and early 20th centuries outlining the molecular components of guano.
One such paper came from a German Chemist called Julius Bodo Unger, who claimed to have isolated the double-ringed purine molecule xanthine from guano in 1844.
But another chemist, Paul Einbrodt, wasn’t so sure. He pointed out that Unger’s molecule didn’t have the same chemical properties that had already been described for xanthine, so it couldn’t be correct.
Unger took a closer look. He published a new paper in 1846, fully describing this novel compound. He named it guanine after its stinky source, oblivious at the time that he was naming one of the fundamental molecules of life after bird poo.
It wasn’t until the 1880s that Albrecht Kossel, who we’ll meet shortly, discovered that guanine was one of the four bases in DNA.
Despite all the financial and scientific interest in guano, one group of people who didn’t do so well out of the bird poop boom were the Peruvians themselves.
The ancient people of coastal Peru highly prized their guano islands and the birds that pooped them into existence.
This reverence was maintained by the Inca colonisers in the region, who placed a death sentence on anyone who killed guano birds or disturbed their nests, and that sentiment continued under Spanish colonial rule.
But by the time the British had got their fingers into the South American pie in the early 1800s, the great piles of guano were seen as being there for the taking. And take they did.
In fact, William Gibbs, who became the richest commoner in England thanks to the guano trade was immortalised in a common rhyme in 19th century London: ‘Mr Gibbs made his dibs selling the turds of foreign birds’.
Millions of tons of guano were dug up by hand - often using indentured labour - and sent off around the world. The birds were scared away and populations shrank as their poop islands were diminished, leaving the Peruvians stripped of their assets with little to show for their white gold than a trashed ecosystem.
The guano boom eventually came to an end when two German chemists, Fritz Haber and Carl Bosch, invented a process to grab nitrogen out of the air and react it with hydrogen to make ammonia - a key component of many nitrogen-based fertilisers (and explosives, but that’s another story…)
As a result, it became possible to produce plenty of fertiliser without the need for sea birds or their poop.
As for Unger, he gave up his career in chemistry and opened a soap factory in Hanover. Perhaps he just wanted to smell of soapsuds rather than bird poo, and who can blame him?
References and further reading:
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