Deep red garnets are found all over the world, from Thailand and Sri Lanka to the Adirondacks. They're even the state gem of New York.
The stones that make their way into rings and necklaces must have a flawless interior. But sometimes garnets are marred with intricate traceries of microscopic tunnels. When Magnus Ivarsson, a geobiologist at the Swedish Museum of Natural History, first saw these tunnels, he wondered what could be making them.
After Ivarsson and his colleagues traveled to Thailand, they found that an assortment of evidence contradicted standard geological explanations for how the cavities might be formed. In a paper in PLOS One, the researchers are floating a new hypothesis: Perhaps what's making the tunnels is alive.
The researchers looked for alternative explanations. One of the most promising was that grains of another stone wore their way through the garnet. However, the mineral doing the tunneling must be harder than the surrounding substance, and garnets happen to be very, very hard. About the only things that could do that to garnet are diamonds or sapphires. But those aren't present in significant quantities where these garnets were found, said Ivarsson.
Furthermore, the tunnels branch and connect with one another in a very unusual pattern, looking a bit like the structures made by some kinds of single-celled fungus colonies. When the researchers cracked the garnets open, they tested the insides of the tunnels and found signs of fatty acids and other lipids, potential indicators of life.
Stuff that helps leeches get their fill of blood
Go for a swim in the wrong shallow lake, and you'll emerge covered in sleek black bloodsuckers that have decided you're their next meal.
But inside a leech, fascinating things are happening.
The slimy creatures manufacture a wide portfolio of substances that help keep blood flowing once they have attached themselves to a host. They don't just latch on to you-they pump out anticoagulants that prevent the wounds they create from clotting too quickly. How else are they going to get their fill?
And once they have sucked your blood-they can consume many times their own body weight in one sitting, or rather, sucking-they're not done. Leeches must also keep the blood from solidifying in their own digestive tract long after they have let go of their host.
"We've had leeches that can live off a single blood meal for a year," said Michael Tessler, a researcher at the American Museum of Natural History who is a co-author of a recent paper on leeches in the Journal of Parasitology, which focused on the anticoagulant genes in leeches' salivary organs.
Medicinal leeches, which have minuscule jaws and which doctors may use to keep blood flowing in the treatment of injuries that might otherwise lead to amputation, have been examined like this before. But Tessler and his colleagues chose eight less-studied types of marine leeches that can feed on creatures like turtles, fish and even sharks.-Veronique Greenwood, New York Times News Service