Will Puddles Overwhelm the Planet?

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Here’s a trick question: How long is the coast of California? Before you Google the answer, consider this: there is no single answer because it depends on how finely you measure things. What looks like two miles of rocky coast from tens of thousands of feet overhead becomes 5 miles of ins and outs when you drop down to 1,000 feet. On the ground with a measuring stick the same shoreline might add up to 20 miles of convoluted nooks and crannies.

If the word “fractal” just popped into your head (or perhaps Zeno’s Paradox of Motion), you are on the right track. Coastlines can exhibit fractal nature, which makes their measurement tricky.

HOWSTUFFWORKS: How Fractals Work

Now consider lakes. Scientists need to know the size and area of lakes all over the planet in order to assess their role in regional and local biological and chemical cycling, including storing and emitting carbon. But lakes may have a fractal nature as well. Some researchers have suggested that the number of small lakes worldwide is underestimated because 1) most small lakes are not even on maps and 2) the smaller the lake, the more numerous they are, which suggests that gazillions of punier and punier lakes make up the bulk of lake surfaces on the planet.

OMG! Is Earth about to be overtaken by fractal-powered puddles?

PHOTOS: Wild Weather Around the World

Not according to environmental scientists David Seekell (U. of Virginia), Michael Pace (U. of Virginia), Lars Tranvik (Uppsala U., Sweden) and Charles Verpoorter (Université de Lille Nord de France). These researchers surveyed lakes in New York’s mountainous Adirondacks and on Sweden’s flat island of Gotland. They have empirical confirmation that fractal nature of smaller lakes works for flatland lakes, but doesn’t apply so well to mountain lakes. The team has published their work in Geophysical Research Letters.

This research is important because it shifts the balance. It means that small lakes probably do not dominate the total global lake surface area and – phew! – have no chance of exceeding the surface area of the planet.

You may now put your wellies away.

Image: Some of Minnesota’s countless lakes as seen during the floods of 2001 (courtesy EROS Data Center and the Landsat 7 science team)

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