"The earliest sawfishes likely arose in the shallow Tethys Sea, that ocean surrounded by the ancient continents of Godwanda and Laurasia, during the Cretaceous period at least 60 million years ago," writes Dr. M. at Deep Sea News.
These "sole survivors of an ancient bloodline" now number only seven species which roam the muddy bottoms of coastal areas, bays and estuaries.
All sawfishes can move easily between fresh and saltwater and often venture deep upstream into rivers. The sawfish lifestyle puts this both their size and saw near humans. All seven species are considered critically endangered by the IUCN. As much as we have impacted them, sawfish have also greatly influenced our culture.
And now, they're one of the most threatened species on our planet. Thanks, humans!
More: Exaltation to Extinction for Sawfishes [Deep Sea News]
Not all snowflakes are unique in their shape. There's one fact for you.
And here's another: The shape of snowflakes — whether individually distinct or mass-production common — is determined by chemistry. Specifically, the shape is a function of the temperatures and meteorological conditions the snowflakes are exposed to as they form and the way those factors affect the growth of ice crystals.
This short video from Bytesize Science will give you a nice overview of snowflake production and will help you understand why some snowflakes are unique, and why others aren't.
I was born in 1981 and, because of that, I largely missed the part of American history where our rivers were so polluted that they did things like, you know, catch fire. But it happened. And, all things considered, it didn't happen that long ago. The newspaper clippings above are from a 1952 fire on Ohio's Cuyahoga river. Between 1868 and 1969 that river burned at least 13 times.
That's something worth remembering — not just that we once let our waterways get that trashed, but also the fact that we've gone a long way towards fixing it. We took 200 years of accumulating sewage and industrial degradation and cleaned it up in the span of a single generation. At Slate, James Salzman writes about that reversal of environmental fortune, a shift so pronounced — and so dependent upon a functioning government in which a diverse spectrum of politicians recognize the importance of investing in our country's future — that it seems damned-near impossible today.
... discharging raw sewage and pollution into our harbors and rivers has been common practice for most of the nation’s history, with devastating results. By the late 1960s, Lake Erie had become so polluted that Time magazine described it as dead. Bacteria levels in the Hudson River were 170 times above the safe limit. I can attest to the state of the Charles River in Boston. While sailing in the 1970s, I capsized and had to be treated by a dermatologist for rashes caused by contact with the germ-laden waters.
In 1972, a landmark law reversed the course of this filthy tide. Today, four decades later, the Clean Water Act stands as one of the great success stories of environmental law. Supported by Republicans and Democrats alike, the act took a completely new approach to environmental protection. The law flatly stated there would be no discharge of pollutants from a point source (a pipe or ditch) into navigable waters without a permit. No more open sewers dumping crud into the local stream or bay. Permits would be issued by environmental officials and require the installation of the best available pollution-control technologies.
The waste flushed down drains and toilets needed a different approach, so the Clean Water Act provided for billions of dollars in grants to construct and upgrade publicly owned sewage-treatment works around the nation. To protect the lands that filter and purify water as it flows by, permits were also required for draining and filling wetlands.
Image from the Blog on Smog, which also has a really nice timeline of cleanup on the Cuyahoga.
Via Laura Helmuth
Atmospheric rivers are meteorological phenomenon that we humans only discovered in 1998 and which supply about 30-to-50 percent of California's annual precipitation. In the NOAA satellite image above, the atmospheric river is visible as a thin yellow arm, reaching out from the Pacific to touch California. Or, more evocatively, reaching out to slap California silly with a gushing downpour.
An atmospheric river is a narrow conveyor belt of vapor about a mile high that extends thousands of miles from out at sea and can carry as much water as 15 Mississippi Rivers. It strikes as a series of storms that arrive for days or weeks on end. Each storm can dump inches of rain or feet of snow.
The real scare, however, is that truly massive atmospheric rivers that cause catastrophic flooding seem to hit the state about once every 200 years, according to evidence recently pieced together (and described in the article noted above). The last megaflood was in 1861; rains arrived for 43 days, obliterating Sacramento and bankrupting the state.
As you might guess, climate change is also involved. Evidence suggests that warming global temperatures could increase the frequency of atmospheric rivers. That, combined with the 200-year event expected soon and the fact we're learning so much much more about these storms, means that you should expect to hear the phrase "atmospheric river" more often.
Scientific American has two interesting stories on the phenomenon right now. The first, which I quote from above, is a blog post by Mark Fischetti. The second is a much longer feature story that gets into the forces that cause these storms and the climate change connection.
Just a few minutes ago, researchers with NASA's MESSENGER mission announced the publication of data that strongly suggests the poles of Mercury contain significant quantities of frozen water.
On the one hand, this is not exactly new news. The possibility of water on Mercury has been a topic of research for something like 20 years. And scientific discoveries tend to move in little mincing steps, not giant leaps, so there have been lots of previous announcements about evidence supporting the hypothesis of water of Mercury — including very similar announcements from the MESSENGER team in December 2011 and March 2012. Your life will not change in any significant way because there is frozen water on Mercury. You probably won't even make a note to tell your children where you were the day NASA announced that ice most likely existed there.
But that doesn't mean this news isn't damned exciting. And it doesn't mean that the scientists involved shouldn't be giddy about it. We are, after all, talking about a mission that sent a spacecraft into orbit around another planet and has quite likely found frozen water sitting on a landscape that is hot enough to melt lead. What's more, they think that ice is covered in places by a thin layer of some coal or tar-like organic material. That is huge news. It's going to change textbooks. And because the scientists think both the ice and the organic material got to Mercury via collisions with asteroids and comets, it's going to be an important part of our ongoing efforts to understand how life begins on planets like Earth.
All of this makes for a really nice, topical lead-in to an essay Robert Gonzalez published on iO9 today. It's totally reasonable to be frustrated by the recent whiplash of hearing that Curiosity discovered something "Earth-shattering" on Mars, only to have that announcement quickly revised to something "interesting" and/or "not insignificant". But, Gonzalez argues, it's also reasonable for scientists to look at something that is merely not insignificant from the public perspective and see it, from their own perspective, as groundbreaking. In fact, he says, we want more scientists who get excited about their work, not fewer.
Read the rest
Gmoke sez, "14-year-old New York student Deepika Kurup was named 'America's Top Young Scientist' for inventing a solar-powered water purification system that changes dirty water into safe drinking water. She is one smart and determined young scientist."
In the United Arab Emirates, a freshwater lake has appeared in the middle of the desert. The oasis is beautiful and full of life, and it's risen 35 feet since 2011. It's also probably accidentally man-made.
Hydrologists believe the lake formed from recycled drinking water (and toilet water). The nearby city of Al Ain pumps in desalinated sea water, uses it for drinking and flushing the toilet, cleans it in a sewage treatment plant, and then re-uses it to water plants. All of that water ends up in the soil and, at the lake site, it comes back up.
The water is clean, writes Ari Daniel Shapiro at NPR. Don't worry about that. Instead, the major side-effect of the lake is change, as scientists watch the desert ecosystem that used to exist on the site decline, and a new one rise to take its place. It's a great story that shows how complicated discussions about ecology can be. On the one hand, you're losing something valuable. At least in this one spot. On the other hand, you're definitely gaining something valuable, too.
"With every species that we lose, it's like rolling the dice. The whole ecosystem could crash down," Howarth says.
But Clark, with the U.S. Geological Survey, says he's not so worried about the desert ecosystem. He says the lake is tiny compared to the vast amount of desert in this part of the world. "If I look through the binoculars, there's, like, seven different kinds of herons. There's greater cormorants. There's ferruginous ducks, which are another very rare worldwide species," Clark says. "There's about 15 of them out here."
This year, three types of birds bred at this lake. They've never been able to breed before in the United Arab Emirates. But this lake, and the others like it, have changed all that. There are fish appearing in these lakes as well. Fish eggs cling to the feet and legs of the herons. So as the birds shuttle between old and new lakes, the eggs fall off and hatch. That's how you get fish in a desert.
When a narrow stream, flowing downhill, meets a wide, significantly-flatter valley, you get an alluvial fan — a place where the flow of water spreads out, slows down, and leaves behind all the rocks and sediment it's no longer moving fast enough to carry. At least, that's how it works on Earth.
Once upon a time, it may have worked that way on Mars, too. Yesterday, NASA announced that the Curiosity rover had documented geology that looks very much like an alluvial fan and rocky deposits that also look very much like what would be left in an alluvial fan on Earth. You can see the comparison of some of those in the image above. In these Martian geological features — as in an Earth-bound stream bed — you find smooth, rounded pebbles and conglomerates, masses of pebbles cemented together over time. The rocks photographed by Curiosity are also too large to have been blown into this sort of arrangement by the wind.
All of this adds to the long string of evidence that Mars once had flowing water on its surface. In fact, reading up for this post, I was surprised to see how much evidence there actually is for this, some direct and some indirect, stretching all the way back to the Mariner 9 orbiter mission in the early 1970s. And, of course, there is water on Mars right now. It's just not flowing water. Previous probes have measured a small amount of water in the Martian atmosphere, and the planet's polar regions contain both frozen carbon dioxide and frozen water. Viking 2 took pictures of frost on the ground in the late 1970s, and in 2008, the Phoenix lander literally dropped out of the sky onto a patch of ice.
Read the rest
It's Anil Dash's 37th birthday, and he's asking his friends and fans to donate $37 to charity:water, to provide clean water for a whole village. His post gives the background on this: he grew up playing with cousins in India, and later in life discovered that the entirety of a neighboring village was wiped out by cholera, with 100 percent mortality.
* I'm running a charity: water campaign to raise $5000 to provide a clean water for an entire village. charity: water is well-known, reputable, efficient, trustworthy and effective in delivering new water wells to areas of the world that need them. I've sponsored wells before, and this is the most meaningful thing we can do. Your entire donation will go to funding water projects, not overhead.
* You should give $37. It's my 37th birthday, and that makes for a nice number. But it's also enough that you'll feel your gift. I don't want this to be a $10 pledge you absentmindedly send to a Kickstarter campaign, or a $5 gift that's "as much as you'd pay at Starbucks". I want you to make a choice, to spend enough money that you have to think about it and compare it to how much you pay for your own water bill. I know you are generous.
* I tell you the story of how the lack of clean water impacts people a part of the world where I have loved ones because I need you to understand that this isn't some abstract threat that happens to "those people over there" living some exotic life you only see in TV specials. People who die, or have their lives dramatically affected, by the lack of fresh water are exactly like me. Their family is from where mine is from, they speak English as well as I do, they use smartphones to communicate, they are like me in every way except their parents didn't get on a jet and come around the world. And as a result, they can be put in mortal danger by having a glass of water to drink.
I've just donated. Will you?
Put all the water on this planet into a single sphere and it would have a diameter of about 860 miles, says the United States Geological Survey. For reference, that's roughly the distance between Salt Lake City, Utah, and Topeka, Kansas.
About 70 percent of the Earth's surface is water-covered, and the oceans hold about 96.5 percent of all Earth's water. But water also exists in the air as water vapor, in rivers and lakes, in icecaps and glaciers, in the ground as soil moisture and earthgwaquifer.html, and even in you and your dog. Still, all that water would fit into that "tiny" ball. The ball is actually much larger than it looks like on your computer monitor or printed page because we're talking about volume, a 3-dimensional shape, but trying to show it on a flat, 2-dimensional screen or piece of paper. That tiny water bubble has a diameter of about 860 miles, meaning the height (towards your vision) would be 860 miles high, too! That is a lot of water.
I really like this illustration because it shows off an important concept: Whether a number represents "a lot" of something or "a little" is pretty damn relative. As the USGS says, that is, in fact, a lot of water. But it also makes for a surprisingly little ball.