To zoologist Robert Higgins, small is indeed beautiful. His infatuation with small creatures -- "meiofauna" (defined) -- dates to a student job in a biology lab that paid 35 cents an hour. Instead of quitting for more lucrative work, Higgins was intrigued.
He'd heard about tiny, amazingly diverse creatures, and learned that some, the tartigrades, lived on moss. So he dumped out the microscopic grains of -- what -- from his specimen pans, put them through a fine mesh, and, using a microscope "found hundreds of organisms."
Forty four years later, Higginns has retired from the Smithsonian Institution, but he's still goggling at meiofauna -- a complex group of animals found in most Earthly environments. One of those non-promising environments is found between grains of sand along the ocean shore. In some environments, if you dig down and grab a handful of sand, you could be holding more biological diversity than a whole rain forest.
A larva of Nanoloricus, in the Loricifera. Courtesy of Robert Higgins.
At least, that's how Higgins sees it. In the course of peering through countless microscopes, he's discovered hundreds of species. Along with Danish biologist Reinhardt Kristensen, he found an entire phylum (defined), called Loricifera.
Meiofauna living between grains of sand have made some fancy adaptations to their harsh environment. Some have hooks on their feet, used to grab the sand. Others have hooked mouthparts, used for locomotion.
Freeze-dried
-- and then some
"It's analogous to a plant seed," he explains, or a bacterial spore. "They can dry up for 100 years, and be rewetted, and come right back to active metabolism," Higgins says. That capability, needless to say, has brought them some interest and notoriety. A drug manufacturer checked out whehter replacing water in membranes with sugars would extend the shelf life of some very expensive anti-cancer drugs (it did, but at too great a cost, Higgins says).
NASA expressed some interest in this capability. While examining the prospect that extraterrestrial life could contaminate Earth, the space agency wanted to check out the worst-case scenario -- that a long-lived life form could come back. But with the increasing -- and perhaps mistaken -- belief that life did not exist in the solar system, there was less emphasis on protecting Earth from life that did not exist.
Finally, of course, there's the "Buck Rogers" slant -- that humans could be placed in suspended animation for long-distance space flights. (Nobody's tried it yet, but there are some other ideas for preservation.
Fun is fun. But, practically speaking, what is the importance of studying stuff that can hardly be seen, doesn't seem to cause disease, and is -- at least to some eyes -- pretty ugly besides?
Among the most incredible adaptations is a kind of suspended animation properly anhydrobiosis, that tartigrades have evolved to survive environmental hazards. The animals do this by somehow replacing water in their cell membranes (defined) with sugar. With the water gone, radiation cannot cause destructive ionization (defined), Higgins explains. Equally, with no water, crystallization does not occur upon freezing. Both changes save the cell membrane from rupturing and killing the organism.
Who
cares about microscopic beach crud?
For one thing, anybody who likes to hang on the sand. "This is the system that helps keep our beaches clean," Higgins explains. "Plankton (defined), bacteria, all sorts of dead material is continually washing ashore, and a lot of kids end up sitting on the sand. There's a certain public-health interest here -- we know, for example, that hookworm can exist on beaches where dogs defecate. And meiofauna, being generalists, may consume hookworms, along with other nematodes. "So if we upset that, we could upset beach cleanliness."
Another member of the Loricifera. Courtesy of Robert Higgins.
Finally, Higgins adds, meiofauna are being touted as possible pollution monitors. The rationale, he says, is that they are in constant contact with water in the sand, and hence are more reliable indicators of pollution than clams, which siphon water from the ocean.
Furthermore, Higgins notes that meiofauna comprise an early step on the food web, and disturbing them could have unforeseeable consequences higher up.
Still, it's hard to escape the notion that most of the motivation here is the pure scientific urge to discover, to classify, to understand. Meiofauna, Higgins notes, were seen under the microscope Anton van Leeuwenhoek invented in 1683.
The key to finding these things, Higgins indicates, in patience, technology, curiosity -- and institutional support. "If you stare through a microscope for hour after hour [these folks love to look at meiofauna!], you have a chance of finding these things, but if you need to get out a certain number of papers each year, you have to take shortcuts and you won't find as much."
What to read more about beaches, then be quick because the beaches are washing away!
Take a sanctioned shortcut with us as we try to get a PANORAMIC PICTURE of life.
