Pollen in pee: fossilised urine from a small African mammal helps us understand past environments Premium

Fossilised urine from a small African mammal helps us understand past environments

If you are allergic to pollen, you are likely to curse the existence of these microscopic particles. You’re not alone: up to 30% of the world’s population suffers from hay fever, which is often driven by pollen allergies. Shifting global climates are likely to push that figure even higher.

However, pollen represents one of the most powerful tools to uncover the nature of past environmental change.

I am the head of the Palaeoecology Laboratory at Nelson Mandela University in South Africa. My research focuses on unravelling the secrets of ancient environments and ecosystems by examining fossil pollen grains. These tiny time capsules hold a wealth of information about the earth’s past. They help scientists to reconstruct ecosystems, track climate change and understand the evolution of plant life.

But it can be difficult to source pollen deposits in arid regions. That’s because such deposits are often found in large lakes, which are in short supply in southern Africa. That’s where an unlikely scientific ally enters the picture: the fossilised urine of a small mammal, the rock hyrax (South Africans call them “dassies”).

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Pollen grains are incredibly durable because they are made of an organic substance (called sporopollenin) that is very resistant to decay. Pollen is released into the air, often in large quantities, and can settle on surfaces like lakes, and become preserved in sediment deposits over thousands, or even millions, of years.

In the lab, we examine the pollen found in these deposits using a microscope. By identifying the different types of pollen grains found within the different layers (representing different time slices) we can reconstruct the area’s vegetation history. Plants grow under specific climatic conditions: for instance, desert plants can grow under low rainfall conditions whereas forest plants need high amounts of rainfall. So we can make inferences about the climate at the time that the pollen was incorporated into the deposit.