Crawford Lake in Ontario, Canada, looks like a pretty normal lake. But as the Washington Post reports, the body of water nestled in the Toronto suburbs has one-of-a-kind characteristics that might make it a sign post in human history. Or more precisely, in our planet's history. Scientists will decide this summer whether the lake should be designated as what's known as the "golden spike"—essentially, the formal starting point—of a new epoch dubbed the Anthropocene. The reason? The lake has a lot going on under the surface, including an upper layer of water and a cold, dark deeper layer under which sediment is perfectly preserved (thanks to a confluence of geological factors detailed in the story). "No other water body is known to possess this particular combination of attributes, making Crawford Lake a unique bellwether of global change," per the Post.
It is, in fact, a "freak of nature" in this respect, says earth sciences professor Francine McCarthy of Brock University in Ontario, who has long studied the lake. By examining the different layers of sediment, researchers can trace telltale signs of human activity. For example, around 1950 (roughly when the new epoch is thought to have started), the mud started showing traces of radioactive plutonium from nuclear tests elsewhere in the world. The sediment also reveals the rise in the burning of fossil fuels, the advent of acid rain, the loss of microbe species, etc. But "it's not just a doomsday story,” says McCarthy, noting that the sediment also shows that humans can reverse things, as when plutonium levels decreased with nuclear testing bans. The International Commission on Stratigraphy will decide in months which of various candidates around the world gets the "golden spike" designation, part of its mission to convince other scientists the Anthropocene era has indeed begun. Read the full story. (More Anthropocene stories.)
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