Was all the water on Earth once urine? The funny question leads to a surprisingly serious scientific explanation of how water moves through the world.
Water is constantly recycled. It evaporates, forms clouds, falls as rain, flows through rivers and, yes, passes through living creatures. According to rough scientific estimates, the amount of urine released over millions of years is so large that much of the water we drink today likely passed at some point through the body of a living creature, perhaps even a dinosaur.
In other words, statistically speaking, there is a good chance that at least some of the water around us has “made that journey” before.
But here comes the reassuring twist: not every drop of water on Earth has such a history. Some water has been trapped for tens of thousands of years in glaciers or deep underground, without taking part in that active cycle. In addition, there is also relatively “new” water that reaches the surface from deep inside Earth through volcanic activity. That water has never been part of the water cycle and therefore has never passed through living creatures.
And staying in the world of waste, a surprising new study has found that ancient squirrel droppings can be a scientific treasure. Frozen samples preserved for hundreds of thousands of years in the soil of northern Canada were found to contain huge amounts of ancient DNA, from plants and fungi to Ice Age animals such as mammoths, bison and horses.
Although squirrels were not predators, they collected food and stored it in their burrows. That helped preserve genetic information from the surrounding environment inside their droppings. The discovery may sound unpleasant at first, but it helped scientists build a more detailed picture of a world that existed about 700,000 years ago, in one of the oldest examples of DNA ever found.
And finally, some good news: will fungi take over the world? This next discovery may surprise even fans of The Last of Us.
Beneath the ground lies an entire world invisible to the eye: a vast fungal network connecting almost all plants on Earth. It is made of tiny threads living in the soil and linking to plant roots, functioning like an underground transport system that moves water and nutrients between plants. In return, the fungi receive energy from the plants.
Researchers examined just how enormous this network is and found something astonishing: if all those fungal threads were connected end to end, they could circle Earth 2.7 trillion times.
The good news is that this network is one of the most important systems keeping life on Earth healthy. About 70% of plants depend on it.