WTF, evolution? —

The more accurate version of this question would really be something like, "Why do some trees fall over in a storm while others stay standing?" The answer is more complex than a simple distinction between old, rotted, and weak vs. young, healthy, and strong. Instead, writes Mary Knudson at Scientific American blogs, trees fall because of their size, their species, and even the history of the human communities around them.

“Trees most at risk are those whose environment has recently changed (say in the last 5 – 10 years),” Smith says. When trees that were living in the midst of a forest lose the protection of a rim of trees and become stand-alones in new housing lots or become the edge trees of the forest, they are made more vulnerable to strong weather elements such as wind.

They also lose the physical protection of surrounding trees that had kept them from bending very far and breaking. Land clearing may wound a tree’s trunk or roots, “providing an opportunity for infection by wood decay fungi. Decay usually proceeds slowly, but can be significant 5-10 years after basal or root injury.” What humans do to the ground around trees — compacting soil, changing gradation and drainage “can kill roots and increase infection,” Smith warns.

Read the full piece at Scientific American Blogs

Come on. It's for science.

In fact, it's meant to help people.

Researchers at Simon Fraser University in Burnaby, British Columbia, Canada, put a dead pig in a shark-proof (and octopus-proof, as you'll see) cage and stuck it in the ocean in order to learn more about how human remains decompose underwater. That knowledge will help forensic scientists interpret crime scenes.

Most of the work is done by maggots known as sea lice, but towards the end, after the maggots have eaten the good bits, you can watch some fat, red shrimp move in to pick apart the cartilage.

Read the full story about this research at New Scientist

Standing, and Falling, two short films by Casimir Nozkowski about the life and death of a big, beautiful, very old tree.

By this point in your lives, most of you are by no doubt aware of the massive slaughter of buffalo that happened in the United States in the late 19th century. Across the plains, thousands of buffalo were killed every week during a brief period where the hides of these animals could fetch upwards of $10 a pop. (The Bureau of Labor Statistics inflation calculator only goes back to 1913, so it's hard for me to say what that's worth today. But we know from the context that even when the value of buffalo hides dropped to $1 each, the business of killing and skinning buffalo was still considered a damned fine living.)

You might think that the business ended there, with dead, skinned buffalo left to rot on the prairie. And you're sort of right. But, in a story at Bloomberg News, Tim Heffernan explains that, a few years later, those dead buffalo created another boom and bust industry—the bone collection business.

Animal bones were useful things in the 19th century. Dried and charred, they produced a substance called bone black. When coarsely crushed, it could filter impurities out of sugar-cane juice, leaving a clear liquid that evaporated to produce pure white sugar -- a lucrative industry. Bone black also made a useful pigment for paints, dyes and cosmetics, and acted as a dry lubricant for iron and steel forgings.

... And so the homesteaders gathered the buffalo bones. It was easy work: Children could do it. Carted to town, a ton of bones fetched a few dollars. Sent to rendering plants and furnaces in the big industrial cities, that same ton was worth between $18 and $27. Boiled, charred, crushed or powdered, it was worth as much as $60.

... By the 1880s, however, a few reporters were expressing nervous awe at the scale of the cleansing, and even despair for what had been lost. In 1891, not 25 years after the slaughter began, the Chicago Daily Tribune ran a dispatch titled “Relics of the Buffalo.” The relics were the animals’ empty pathways and dust wallows, worn into the surface of the Manitoba plains over countless years. The bones, let alone the living creatures, were long gone.

Cancer threatens Tasmanian Devils with extinction by "devil facial tumour disease" —

In the last 2 decades, some 85% of wild Tasmanian Devils have been wiped out. The primary cause isn't poachers or habitat destruction, but a bizarre kind of *contagious* cancer. "A recent epidemic disease, known as devil facial tumour disease, has brought an extremely rare, but equally devastating, set of circumstances together to threaten the devil population. Facial tumour disease, unlike every form of cancer known to affect humans, is transferred directly from devil to devil when they bite each other, which is 'something they do a lot during feeding or mating.'” — Xeni •

This is probably the most amazing thing I learned all weekend. The Amazon rainforest—with all its plant and animal life, and all its astounding biodiversity—could not exist as we know it without the patch of African desert pictured above.

The rainforest is amazing, but the soil it produces isn't very nutrient rich. All the minerals and nutrients that fertilize the rainforest have to come from someplace else. Specifically: Africa. Scientists have known for a while that this natural fertilizer is crossing the Atlantic in the form of dust storms, but science writer Colin Schultz ran across a 2006 paper in the journal Environmental Research Letters that not only produces evidence for a much larger trans-oceanic transfer of dust than was previously assumed ... it also pinpoints the exact (and astoundingly small) location where all the fertilizer in the Amazon is coming from.

The research paper, itself, is pleasantly readable, as far as these things go, so I'm going to quote directly from it. One quick note before I launch into this quote. The authors are measuring the mass of the dust in teragrams (or Tg). As you're trying to wrap your head around this, it might be helpful to know that 1 Tg = 1 million tons.

A total of 140 (± 40) Tg is deposited in the Atlantic ocean and 50 (± 15) Tg reach and fertilize the Amazon basin. This is four times an older estimate, explaining a paradox regarding the source of nutrients to the Amazon forest. Swap et al suggested that while the source for minerals and nutrients in the Amazon is the dust from Africa, it was estimated that only 13 Tg of dust per year actually arrive in the Amazon. However, they pointed out that 50 Tg are needed to balance the Amazon nutrient budget.

Here we show a remarkable arrangement in nature in which the mineral dust arriving at the Amazon basin from the Sahara actually originates from a single source of only ~ 0.5% of the size of the Amazon: the Bodélé depression. Located northeast of Lake Chad (17°N, 18°E) near the northern border of the Sahel, it is known to be the most vigorous source for dust over the entire globe.

Basically, these 2006 calculations account for all the fertilization needs of the Amazon, while previous calculations left a weird gap in between the amount of dust the rainforest needed and the amount the scientists thought was getting there.

Also: The place the dust is coming from is a single, highly specific region. As Alexis Madrigal pointed out at The Atlantic, we're talking about a patch of desert only 1/3 the size of Florida supplying the nutrient needs of a jungle that is roughly the same size as all 48 contiguous United States. Mind, blown.

Read the full research paper at Environmental Research Letters

Check out The Atlantic's write up on this, including a satellite photo of the dust storms in question.

Follow the guy who started it all—the very smart, very entertaining, and very tall Colin Schultz

Via Bart King

How not to conserve wildlife —

Clever whale sharks have figured out that fishing nets contain a lot of tasty fish. More importantly, they've figured out that they can suck those fish out of the net through holes in the net material.

The downside: When the sharks swim into fishing areas, looking for nets to suck, they can end up caught in the nets themselves. Conservation International took this video, showing why the sharks are hanging out around nets to begin with, as part of a series of videos documenting new net designs that can keep the fishies in and the whale sharks out.

Check out the rest of the video series

Via Charles Q. Choi