How Civil War Engineers Tasted A Cretaceous Sea

In 1864, the US Army began digging a proper well for Fort Monroe, a Chesapeake Bay Union fort surrounded by then-Confederate Virginia. Three years into the Civil War, and cut off from the state it was built to defend, Fort Monroe had more wounded soldiers and escaped former slaves than it could handle, and its insufficient surface wells had already forced a small-scale “invasion” of Virginia to secure enough water.

After five years of digging (long after the Civil War ended), the Army’s well was 907 feet deep . . . but no matter how deeply they dug, the well was bringing up only saltwater!  And salty saltwater, twice as saline as the Atlantic.  Subsequent attempts at digging wells also turned up only the same salty brine.  The aquifers underground were fed by rain, and sloped down from the inland west; by all rights they should have been salt-free.  Yet the salt ran deep and wide, fouling water wells on both sides of the bay.

But why?  The US Army in 1860s Virginia certainly didn’t know, nor did anyone else at the time.  It would be 114 years later, and 190 miles away, that the first significant clue would finally appear.

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The Secret Lives (and Deaths) of Leaves

A leaf

It’s autumn now, and the trees outside my window have already burst into brilliant shades of yellow and red. Soon their gorgeous leaves will fall to earth, ready to be raked, bagged, and shipped off to Pacific Region Compost.

It seems a little wasteful; these trees have put a surprising amount of energy into growing something that only lasts for six or seven months. In a 2002 study, researchers looking at 14 California blue oaks found that, by July, each of those oaks had invested about 6.6 kg of new plant material in their leaves. (This is dry mass, not including the ~85% of the leaves that were water.) One outlier had 29 kg of dry leaf mass, which in life could have weighed about a quarter-ton.

6.6 kg (or even 29 kg) might seem like chump change for a tree weighing several tons, but remember that trees need hundreds of years to get that big. Annual tree growth can be measured in the low tens of kilograms per year . . . so that extra 6.6 kg of leaf-matter represented a significant fraction of the tree’s net production, poured into something that it would soon toss aside like so much trash.
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You Have Better Taste Than You Realize

The old “tongue map” from our elementary school textbooks has been roundly debunked. Experimental confirmation of “umami” expanded Westerners’ traditional four basic tastes—sweet, sour, salty, and bitter—into five. But did you know those 5 basic tastes might actually be 6 . . . or 7, 8, or more?

Advances in the technology and techniques available to researchers have led to significant new discoveries in taste perception. Receptors have been discovered in the last few years for “tastes” long assumed to be entirely smell or texture dependent. What tastes have you been tasting your whole life without even knowing it? Continue reading “You Have Better Taste Than You Realize”

How Do We Know The Continents Are Moving?

50 years ago, “continental drift” was a fringe hypothesis rejected by most geologists. Today the theory of plate tectonics (which includes continental drift) is universally accepted as true, and unifies once-separate areas of geology under one grand banner.

There are mountains of evidence (literally) that plate tectonics has taken place in our planet’s past. But how do we know that the continents are still drifting, right now? And how do we know what direction each one is moving, how fast they’re going . . . how do we know what we know about plate tectonics? Continue reading “How Do We Know The Continents Are Moving?”

Academic Urban Legends: Is Spinach A Good Source Of Iron?

Spinach is a great source of iron! Except no, no it isn’t. That was debunked in the 1980s . . . someone misplaced a decimal point in the ’30s, and everyone since has thought it had 10 times more iron than it does. Or was it the 1890s? Or . . ..

Writing in Social Studies of Science, author Ole Bjørn Rekdal shares the weird, twisty, fascinating story of how “academic urban legends” like this get going, and keep going long after they’re debunked. It seems both the false idea that spinach is a good nutritional source of iron, and the subsequent urban legend that that urban legend got its start as a misplaced decimal point, have been widely believed and spread by highly-educated people in the health sciences field of study, years or even decades after they were debunked. Continue reading “Academic Urban Legends: Is Spinach A Good Source Of Iron?”