Women in the WORM FORCE Assistant professor at UMaine finds complex and beautiful world in state’s intertidal mud flats

It’s not hard to find Sara Lindsay at the Darling Marine Center in Walpole on a crisp, sunny fall day. She’s the one wearing jeans and rubber boots, carrying a sample tray and a plastic bucket. As she often does, she’s walking through the woods that fringe the estuary, en route to the mud flat at Lowe’s Cove, to grab samples of worms that live in the sediment.

To most of us, the intertidal flats along the Maine coast can appear drab, barren and lifeless, vast expanses of sucking mud between the shore and the water. But Lindsay, an assistant professor of marine sciences at the University of Maine, sees a world that’s fascinating, complex and even beautiful in the life of the mud flats, especially in some of their most abundant yet unseen denizens, the mudworms of the Spionidae family, spionids for short.

“I can certainly tell you a whole lot about who the worms are from this log to that rock,” she says gesturing at the typical Maine mud flat before her, exposed by low tide. Not only have these worms provided Lindsay with years of research, they also have become the subjects of her award-winning photographs, beautiful close-up images shot through microscopes.

Lindsay’s attraction to the shore began as a youth in landlocked Athens, Ga. Her father, a University of Georgia biology professor, would pile the family into a station wagon each summer and travel cross-country – camping and seeing the sights along the way – to his summer research station at Friday Harbor in the state of Washington. Spending time along the shore, Lindsay developed a fascination that has never gone away.

After earning a doctorate from the University of South Carolina, where she spent time tromping the coastal marshes, and doing postgraduate research on bioluminescent shrimp at the Scripps Institution of Oceanography in San Diego, Lindsay and her husband took jobs at the University of Maine in 1998.

Her worm research has led her to some interesting age-old questions about how and why some animals regrow amputated body parts. The mudworms that Lindsay studies can grow back their tails. It’s a good attribute because, like many mud-dwellers, worms get attacked by “prey nippers” – predators such as gulls and flounder that bite off just the bit of the worm that’s exposed above the mud.

Growing back a tail is one thing, a head quite another. But these worms are able to do both. “Some of the worms lose their heads to predation,” says Lindsay. “Within three days, they’ve started regenerating a nervous system. Within 10 days, they’ve regrown most of their brain.” And if the worms lose their heads and their tails? They can still recover. “If they lose their heads and their tails at the same time, they regrow their heads first,” says Lindsay. What if they lose their heads twice in a summer? “It takes a little longer the second time around,” she says.

So many seemingly primitive animals, hydras and newts most famously, can regrow missing body parts, but humans lack this ability. “Why has it been lost?” asks Lindsay. “Why can’t we regenerate our limbs?”

There are many other injury-related questions that interest her. The worms are constantly mixing the sediments – some live tail-up and move sediment up to the surface, others live head-up and move surface sediment to the depths. How, Lindsay wonders, do injuries affect the rate of mixing?

And there’s another research project she’d like to get back to. In research published in 1998, Lindsay found that larval worms tend to avoid spots on the flats that show a lot of disturbance, where they quickly could become another critter’s lunch, and that they do this by chemoreception, probably by detecting the ammonium and oxygen levels associated with disturbed mud. That research led her to studying chemoreception in adult worms; eventually she would like to get back to looking at larvae.

Lindsay’s enthusiasm for the wriggly invertebrates is apparent, but she says it’s sometimes difficult to convey it to others. “My grandmother would look at me and say, ‘Sara, why are you studying worms and mud?'”

Clearly, these are interesting creatures, but beautiful? “That takes a little more convincing,” says Lindsay. In recent years, the convincing has become a bit easier, through the dramatic color photographs Lindsay has been taking of the worms. The images, some at 630x magnification, reveal the worms’ neural pathways and sensory organs, and, yes, they are beautiful.

Again, Lindsay’s father, David, has been an influence, helping her with tips on photography and Photoshop. (Her photographs are featured in the September-October issue of UMaine Today). Lindsay is earning a national reputation for the images: In 2006 she won the Ralph and Mildred Buchsbaum Prize for Excellence in Photomicrography from the American Microscopical Society; in 2005 she won honorable mention in the Olympus Bioscapes International Digital Imaging Competition.

Even on the mud flat, Lindsay seems to have the eyes of an artist. Bending down and looking closely at the flat, Lindsay observes the mud flat has a “golden brown sheen” but she says it’s nicer in the spring when diatoms bloom. She breaks open the tube of a bamboo worm and notes the “nice golden color” of the oxygenated soil next to the worm.

“If you take the time and look carefully, you can see the trails of the snails, you can see the clams squirt at you,” Lindsay says. She points out some tiny, skinny brown cylinders barely visible on the surface of the mud. “These are feces made by worms,” she says. (It turns out there is tremendous variation among worm feces on the mud flat. Some worms make little dark footballs, some make a diarrhea mound, others make toothpaste spirals.)

The tide is creeping in over the mud, and hermit crabs and shrimp are moving around in the clear shallow water. Lindsay has nearly all of the samples – trowel-dug plugs of worm-riddled mud packed neatly in urine-sample jars -she needs to study the worms back at her lab in Orono, but she needs to grab one or two more.

“See all these little pimples? These are worm tube tips,” says Lindsay pointing at a patch of mud at her feet. “Let’s see if I can find something here.”