The Hidden Gems of Lake Michigan

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A professionally polished Petoskey stone, similar to what you would find for sale in shops throughout Michigan.  The diagram in the corner indicates scale. Photo by Dr. Mark Wilson of the College of Wooster, Ohio, via Wikimedia Commons.

This summer, transport yourself to the eastern shore of Lake Michigan, near the town of Petoskey, and perform a geological magic trick. Take a chunk of limestone on the beach – bland, grey and completely featureless – and dip it into the lake. Stare into the translucent depths at your chosen stone and watch distinctive hexagonal patterns emerge on the surface. But a funny thing happens when you pull the stone out of the water and let it dry in the sun – the markings abruptly vanish! What’s going on here?

As you might have suspected by now, this is no ordinary piece of limestone. Instead, you’ve stumbled across a Petoskey stone, beloved by geologists and beachcombers alike. Like all magic tricks, however, there is indeed a simple explanation for the vanishing act, impressive as it appears on first viewing. In this case, our mysterious rock’s origins in the distant past owe just as much to the animal as the mineral.

Four hundred million years ago in the Devonian era, Lake Michigan did not exist, but there was no shortage of water in the area. A wide, shallow tropical sea covered the area, home to a diverse array of bizarre-looking marine life: horseshoe crab-like trilobites, spiraling ammonites, brachipods and other shellfish, the first jawed fishes, sprawling crinoids and crustaceans. (When T.S. Eliot has J. Alfred Prufrock mutter, “I should have been a pair of ragged claws / Scuttling across the floors of silent seas,” he was probably thinking of the Devonian.)  It was also a golden age for coral, including one family – now extinct – known as rugosans, or “wrinkled,” on account of their distinctive appearance.

While many of these rugosan corals were solitary polyps, other species opted for a more communal approach. They massed together, forming vast reefs similar to the ones we see in our own era off Hawaii or Australia.  One of these colonial coral species, Hexagonaria pericarinata, was particularly abundant around the future home of Petoskey, Michigan. As the scientific name suggests, these corals were highly symmetrical, with each animal forming distinctive six-sided walls as it tried to occupy the maximum possible space against its many neighbors. (Unlike the rigid chambers you see in honeycombs, you’ll often find five, four, or even three-sided corals who just couldn’t grow up fast enough to compete with their more aggressive counterparts, or asymmetrical hexagons formed by polyps that got “squashed”.)

When individual polyps died, others grew on top of them and the cycle repeated. Eventually, whole reef conglomerates were buried by ocean sediments in the shifting seas. Time and pressure transformed the coral and sediment matrix into calcium-rich limestone, the coral polyps preserved as flattened outlines of their former, three-dimensional selves in the rock. Each polyp’s alimentary canal became a dark speck that forms the “eye” of each hexagon; the lines that radiate outward from the center mark where tentacles were located.

Fast forward to twelve thousand years ago in the Pleistocene. The tropical ocean vanished long ago, replaced by bare stone and a wall of glaciers three miles high. As the glaciers advanced and retreated, they scoured the bedrock, kicking up chunks of the limestone reefs and gouging out the depression that would fill with meltwater and become Lake Michigan. Rounded and sculpted by water, the fossilized coral fragments were moved by centuries of robust freeze-thaw cycles southward in the lake, occasionally washing up on beaches tens or even hundreds of miles away from their original site.

Dubbed “Petoskey stones” because of their abundance on the beaches and bedrock of Petoskey, Michigan, these stone corals are ubiquitous in gift shops throughout the state. You can find their likeness on a number of “Petoskey tchochkes” including magnets, bumper stickers and t-shirts, so residents and tourists alike can proclaim their love. As a sign of their distinctive popularity, Petoskey stones have been the official state stone of Michigan since 1965. They remain a source of local pride and a prize find during any lakeside stroll. Most stones you find on the beach are tiny, but huge storms can wash five, ten, or even twenty pound specimens out of the lake overnight.

Why are they easier to spot in water? The contrast between the slightly lighter crystals of fossilized coral body (calcite) and the surrounding stone is greatest when wet, making them easiest to detect underwater or well within the splash zone of the lake. (Further away from the lake shore, less discriminating rockhounds opt for spittle or other body fluids as a way to test their finds.) Some stones will naturally keep their appearance without water or any further treatment, but most of the stones available for sale have been professionally polished to ensure that the distinctive hexagons remain visible even when dry.

You can replicate the same look on stones you find on the shore with some fine-grit sandpaper, elbow grease, and a little toothpaste and velvet cloth for polish. Limestone is soft and easily eroded, so a little bit of effort goes a long way – a conventional rock tumbler is overkill, converting beautiful stones into a dusty pile of sediment. But maybe you’ll keep any stones you encounter in their natural state, tucked away in your pocket, ready to perform a magic trick of your own.

The Noble Sporophyte

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Moss sporophytes emerging from a clump of moss. By Bob Blaylock. Image licensed under creative commons by Wikipedia.

Moss sporophytes are tiny, slender structures that pop out of moss in droves. Their beauty, diversity, fun-factor, and cute little caps continually amaze me. Like a big buzz cut, they tickle my hand as I graze them. If I am lucky, they are ripe and release their spores in a small flurry, sending a miniature cloud of dust eight inches forwards. The spores melt away into the air, quickly invisible to the naked eye. Usually, I brush the clump again and again, and the sporophytes repeat the trick until the caps are emptied of their spore dust. Eventually, some of the spores will germinate to grow new moss plants.

Once the caps pop off the sporophytes, you can tell they are ripe or almost ripe. By Hermann Schachner. Image licensed under creative commons by Wikipedia.

Over the five years that I earned my living teaching outdoor programs, I taught several hundred people about sporophytes. I would have the group help me find a promising patch of moss, and with reverent enthusiasm, I would show my students the petite sporophytes. Then, I would share the three reasons that sporophytes had captured my heart to become one of my favorite things in the forest.

First of all, I didn’t know that they existed until I was in my 20s, and once I knew to look for them, I saw them almost everywhere there was moss. This was an astounding discovery, and one of the most poignant, eye-opening experiences of my college years. I had been oblivious to the ubiquitous and entertaining sporophytes all around me, and it was amazing to have my eyes opened just by learning to look for them.

An example of moss sporophyte diversity and elegance. By Vaelta. Image licensed under creative commons by Wikipedia.

An example of moss sporophyte diversity and elegance. By Vaelta. Image licensed under creative commons by Wikipedia.

Next, I would demonstrate the gorgeous diversity of the sporophytes. The stalks are often iridescent, and many of them exhibit a gradient of hues. For example, some range from gold to deep, metallic purple.The spores are also often brightly colored, sometimes in surprising ways. I have dissected sporophytes that revealed bright orange, white, or dayglow green spores. And the stalks are always fine and flexible, which means that they “boing” in a tactilely-satisfying way.

Finally, I would show the participants, adult or child, how fun sporophytes are by running my hand through the tuft. If I judged the clump well, and was lucky, a cloud of spores would gently whiff from the cluster of stalks. Everyone would take turns helping the spores fly free. Invariably, some excited participants would spend the rest of the program looking for other clusters of ripe moss sporophytes.

A close-up of a sporophyte capsule. By Bernard DuPont from France. Image licensed under creative commons by Wikipedia.

A close-up of a sporophyte capsule. By Bernard DuPont from France. Image licensed under creative commons by Wikipedia.

Moss sporophytes illustrate some of the most important reasons that humans need the natural world. They invoke wonder, are beautiful and fun, boggle minds with their diversity and scale, and inspire curiosity. For those who have never really noticed them, they encourage humility by reminding us how little we see and understand each day, even when it’s right in front of us. Moss sporophytes provide an opportunity for people to interact with nature in a hands-on way, and in doing so, people help the little plants send their spores into the wind. The experience is tactile, guilt-free, and doesn’t require any special equipment.

As the spring rains feed the forests, fields, and yards around you, keep an eye on your local moss patches. The mossy marvel of a ripe sporophyte might be waiting at your feet.

The moss life cycle. The green moss is the gametophyte, which gives rise to sperm and eggs, which combine to grow a sporophyte from the tip of the gametophyte. The spores germinate to grow more gametophytes (the green moss). By Htpaul. Image licensed under creative commons by Wikipedia.

The moss life cycle. The green moss is the gametophyte, which gives rise to sperm and eggs, which combine to grow a sporophyte from the tip of the gametophyte. The spores germinate to grow more gametophytes (the green moss). By Htpaul. Image licensed under creative commons by Wikipedia.

Secrets of The Vault

Sean and I are in The Vault. We’ve been here for a while—hours now. It’s less grandiose than it sounds, really just a back room in the Charlotte Town Hall, but it gives me the same feeling I get from the New York Public Library or a fancy art museum. Tread lightly, the walls are saying. Look closely. We have secrets for you.

Inside The Vault. Photo by Samantha Ford.

Inside The Vault. Photo by Samantha Ford.

What’s amazing is that the secrets of The Vault are not really secret at all. Every document in the room is in the public record, even the original map of the Town of Charlotte, hand-drawn in 1763. The massive red books of land records, the card catalogues of births and deaths—these pages of history are not preserved behind glass; we are perfectly free to look at them. I can reach out a hand, every now and then, to gently trace this two-hundred-and-fifty-year-old calligraphy.

We’re here to research the UVM Natural Area at Pease Mountain, a prominent hill directly west of the Charlotte Town Hall and just north of Mount Philo along the Champlain thrust fault. This semester, our cohort is performing a Landscape Inventory and Assessment of the area. We’ve spent several weekends strolling along the mountain’s broken quartzite ledges, and we’re starting to get a sense of the property’s natural resources. The soil is thin but rich, patterned here and there with the frostbitten remains of last year’s hepatica leaves. The trees are not the usual beech-birch-maple assortment we expected, but a variety of species used to warmer, drier climates: peeling trunks of shagbark hickory, gnarled red oaks, bitternut hickories with their sulfur-yellow buds. We’ve noticed hints of other mysteries: a road cut here, an old stone foundation there. UVM acquired the property in 1949; Sean and I want to know who has owned Pease Mountain–and what it’s been used for–as far back as the town’s records go.

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First subdivision of the town of Charlotte.

We start by looking in the Index, a twenty-pound tome containing a list of every land transaction undertaken in Charlotte until the book ran out of pages around 1960. Thankfully the Index is alphabetized and we quickly find the record we need: “Jeanette S. Pease Phelps and George J. Holden to University of Vermont and State Agricultural College.”

I’m immediately absorbed in the web of archaic legalese that follows: “Now, know ye, That pursuant to the license and authority aforesaid, and not otherwise…We do by these Presents, grant, bargain, sell, convey and confirm unto the said University of Vermont…the following described land…Being Pease Mountain, so-called, in the town of Charlotte.” The deed was written barely more than half a century ago, but it reads like something from the middle ages. The solemn tone is compelling. I can picture the occasion, the buyers and sellers grouped around a table, poised to sign below the words, “In witness whereof, we hereunto set our hands and seals…”

Original charter of the town of Williston. Photo by Samantha Ford.

Original charter of the town of Williston. Photo by Samantha Ford.

We follow the trail further and further back, tracing property descriptions bounded by increasingly vague terms: “…to the N.E. corner of said lot to a maple stump with a cedar stake in said stump. Thence southerly on the west line of said owned by Everett Rich to a cedar stake & stones in the S.E. corner. Thence westerly on the north line…” The record books get thinner as we travel back in time, the pages more brittle, the writing fainter. Eventually we find ourselves scrutinizing a gridded map: the second subdivision of the town.

Accompanying the map with its numbered parcels, we find a list of the original owners of those parcels. Lot number 1, which at the time encompassed most of Pease Mountain, is ascribed to “Glebe for the Church.” We puzzle over this. Who was Glebe? We haven’t heard any mention of him in more recent deeds. Was he a minister?

Glebe for the Church. It sounds like a momentous designation. We finally think to Google the strange phrase, and we discover the ancient tradition of glebe land. It’s not a person after all, but a kind of conservation easement. When Vermont’s first towns were established, certain plots of land were set aside to remain undeveloped. These lands were leased to farmers or timber harvesters in exchange for a rental fee, which paid for municipal costs or, in this case, the upkeep of the parish. For hundreds of years, Pease Mountain was preserved by this tradition.

Mysterious stone structure found on Pease Mountain.

One of several mysterious stone structures found on Pease Mountain.

As we leave the Town Hall, Sean and I glance up at Pease. Our journey through the handwritten history of Charlotte has given us a deeper sense of this place. As we’ve walked there with our cohort we’ve mapped natural communities and forest stands, discovered vernal pools and views over the lake. But walking and looking can only take us so far back. Beyond the oaks and hickories, the purple cliffs, the porcupine and bobcat dens, there is another Pease Mountain story. It’s no longer legible in the landscape. But luckily for us, it’s all written down in the record books.

Julia Runcie is a first-year student in the Ecological Planning program.

A [Local] Monster Mash

Here in Vermont you can hardly go outside without seeing signs about buying local.  Local foods are labeled in grocery stores, restaurants proudly display maps of Vermont with pins pointing out where they source their ingredients, and everybody who’s anybody seems to have a CSA share. But for some reason every year around this time even the most devout locavores import their Halloween monsters from far away.  Mummies more at home in Egypt smile out at you from windows, tarantulas usually found in tropical regions crawl all the way into candy bowls in Vermont, and vampires hop planes from Transylvania to lurk on residential porches for a few weeks every October.  Enough!  I say it’s time to put an end to the madness of imported creepies and crawlies, and to get to know a few of our own.  And so, I present to you a Halloween line-up of locally and sustainably sourced (and not-so-scary) monsters:

The Stigmata Mummy-Wasp (Aleiodes stigmator)

Mummified Acronicta Caterpillar with exit-holes of Stigmata Mummy-Wasp, photo by Bryan Pfeiffer

Mummified Acronicta Caterpillar with exit-holes of Stigmata Mummy-Wasp (Photo by Bryan Pfeiffer)

Here’s the good news: the stigmata mummy-wasp didn’t make the monster list for having a painful sting. In fact, these wasps are small and don’t have stingers.  In place of a stinger on their hind end, these wasps sport an ovipositor, which they use to inject their eggs under the skin of an innocent and unsuspecting host caterpillar.  After the eggs hatch the wasp larvae chew a hole in the underside of the caterpillar, causing it to leak fluids that dry and essentially glue the caterpillar to a plant.  Next the larvae mummify the caterpillar by eating the soft innards and lining the empty body with silk.  Inside the hollow caterpillar husk the wasp larvae spin their own cocoons and pupate into adults.  When they emerge from their cocoons they chew their way out, leaving behind the dry husk of a caterpillar that looks like it has been sprayed with buckshot.

Even though this may sound straight out of science fiction, stigmata mummy-wasps are native to Vermont where they generally inhabit wetlands and floodplains.  Though the wasps themselves are small and hard to find, the mummified caterpillars are not.  Their riddled mummies can be found clinging to sticks year round, and if you find one in late fall you might want to watch it closely – you might be lucky enough to spot one of these little monsters emerging.

The Oleander Aphid (Aphis nerii)

Oleander Aphids on a stalk of Swamp Milkweed

Oleander Aphids on a stalk of Swamp Milkweed

There are many types of aphids, but while I was researching for this list one variety stood out: Oleander aphids.  These little orange and black bugs grab onto a stalk of milkweed (or any of several other plant hosts) with specialized sucking mouthparts and drink it dry.  Their story only gets weirder from there.  Oleander aphids develop from unfertilized embryos and all adults are female; males do not occur in nature.  Adult females can be winged or wingless, the former usually showing up when the host plant is overcrowded or dying so that they can fly off to infest a new host.  Both the winged and wingless adults excrete live nymphs instead of eggs, and a colony can grow quickly.  The nymphs develop through five different phases before becoming adults, but nearly all phases look the same and vary only in size.

If an army of jack-o-lantern colored female clones sucking the life out of a plant isn’t Halloween enough for you, I should also point out that oleander aphids have their own mummifying parasitoid wasp.  The aphidiid wasp (Lysiphlebus testaceipes) lays a single egg inside an aphid nymph or adult.  When the egg hatches the wasp larva consumes the aphid from the inside, so that it develops into a brown papery husk of its former self.  Much like stigmata mummy-wasp larvae, the wasp larva then spins a cocoon inside this mummified aphid, pupates, and chews its way out, leaving behind a bloated brown aphid mummy with a hole in it.  When a dense colony of oleander aphids is heavily parasitized, half or more of the aphids in the colony may eventually be only mummified remains while their sisters slurp placidly beside them.  How bewitching.

Horsehair Worms (Paragordius varius)

Resembling an animated, wiry strand of hair, horsehair worms are often spotted writhing in the bottom of woodland streams and pools. As charming as that may sound, their mating behavior is less than romantic.   When a female indicates a willingness to mate, the male releases a cloud of sperm in her general vicinity, and then swiftly dies.  The sperm forms a glob, which finds its way to the appropriate receptacle on the female within the next 24 hours.  A fertilized female goes on  to lay as many as 6 million eggs, and then she too perishes.  As It turns out this is the least offensive part of their life cycle.

Horsehair Worm (on top of leaf) found in a stream in Bristol, VT

The eggs mature, and in 2-3 weeks millions of tiny worm larvae are hunting for hosts in the pool or brook.  They infect many different kinds of aquatic phase insects, including mosquito larvae, and when the infected larva matures into its adult phase, the worm larva comes along for the ride.  Eventually this intermediate host insect is consumed by the host the worm is really looking for: crickets and their relatives.  Once inside this final host the worm begins to absorb nutrients through its skin from the host’s body.  Having no mouth or digestive system of its own, the worm requires an environment where food comes pre-digested.

While growing inside its host, a process that takes 2-3 months, the worm is also practicing mind-control.  An infected cricket will not chirp at all as chirping uses up precious energy and can attract unwanted attention to the worm’s comfortable home. Once the horsehair worm has fully developed inside of its cricket host (reaching lengths of four inches or more), it releases a chemical that drives the host to seek out water.  Meanwhile the worm has carved a hole in its host’s side, and shortly after the host hits the water the worm will emerge in its free swimming adult phase to mate, leaving its injured but still living host behind to begin the cycle again.

From the mummified remains of caterpillars, to the mind games of a parasitic worm, our Vermont backyards boast a roster of Halloween monsters rivaling those of the silver screen.  So this Halloween, when you find yourself telling scary stories with friends, borrow a tale right from your own backyard…and sustainably source your monsters.

Shelby Perry is a second year student in the Field Naturalist Program.  She would like to acknowledge Field Naturalist Graduate, Charley Eiseman, for his help fact-checking sections of this post, and his wonderful book Tracks and Sign of Insects and other Invertebrates: A Guide to North American Species.  

Freshwater Sharks

Snorkeling in frigid waters for a species at-risk

By Levi Old                                                               

Salvelinus confluentusOn a dead-still summer night, I army-crawl upstream.

“We have a large adult!” says Jen.

I rise to one knee and pull the fogged snorkel mask off my head. “A big one?” I mumble in a haze.

“Yeah, really big. Much larger than I’ve ever seen this far up the creek,” she replies, pointing to where it kicked its caudal fin gently against the downstream flow. “It’s right there beside you.”

I cinch the mask on my face, place the snorkel in my mouth, and dunk back into the frigid water:

Twenty-six inches of wildness.

Jen pops her head out of the water and says, “Isn’t that just a beautiful creature?”

She snorkels one side of the creek and I snorkel the other. An assistant in waders walks the creek, tallies our fish sightings and makes sure we do not go hypothermic. Continue reading

Beyond a Collection of Facts

By Clare Crosby

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I spent my childhood hosting acorn cap tea parties for fairies, scurrying on calloused feet to collect eggs from the chicken coop, and reenacting Little House on The Prairie in the meadow behind my house, just east of Austin, TX. I did not suffer from “Nature Deficit Disorder.”

But as I grew, my interests shifted. I traded the meadow for well-manicured athletic fields and our old pond for swimming pools. My interest in my Central Texas natural surroundings paused around 8 years old. I never figured out what species of oak provided teacups for my parties, only that the caps were nicely proportioned for fairies. Neither did I learn what type of moss my fairies used for seat cushions, only that it opened into minute stars under sprinkled water.

I’m embarrassed now, as a naturalist, to admit that I don’t know even some of the most common species of my home state. This lack of knowledge, however, offers opportunity when I return to Texas from Vermont, the home of my formal ecological education. As I walk old trails and come across a familiar (yet unknown) tree, my inclination is to turn to field guides or a trusted expert to tell me what to call it, who eats it, and what it might reveal about the soil beneath it. In Vermont, I have had a string of wonderful professors and peers to teach me about the natural world, assisted, of course, by an ever-growing library of field guides. I hope to be so lucky again in Texas. Continue reading

What’s in Your Backpack?

Rattling My Bones

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Dripping with cultural history and utterly unique, the objects cradled in Connor Stedman’s excited hands burned with sentimental value. Their glow reflected in Connor’s eyes and didn’t flicker for an instant upon the delivery of my first question.

“So, what are they?”

To the untrained eye, they were two pieces of wood roughly the size and shape of tongue depressors, but slightly heftier and square at the ends. Connor explained it was a set of bones: A historically Irish one-handed musical instrument that is played by holding one bone stationary while rattling the other bone against it.

While the traditional instrument was made from sheep’s bones, Connor’s version originated as the South American tree palo santo, or “holy wood” in Spanish. Palo santo’s use as a good luck charm and a cleanser of bad energy dates back to the Inca era. Connor says that he’s never heard of another pair of bones made from palo santo.

Connor carved his bones in anticipation of a local visit by Irish bard Gerry Brady, who described bones as “the only instrument you can play with a pint in the other hand”. Gerry blessed this set of bones himself. Continue reading

The Burlington Naturalist Scavenger Hunt Series: Williston’s Muddy Brook Wetland

A special series of blog posts brought to you by Liz Brownlee 
The Burlington Naturalist Scavenger Hunt Series: Discover the area’s hidden gems.  Hone your naturalist skills.  Learn to see the treasures along every walking path, trail, and creek.
This series of scavenger hunts is a chance to get outside, look closely at the world around you, and enjoy nature.  The hunts are designed for budding naturalists of any age.
 
Hunt I: Williston’s Muddy Brook Wetland
 
Cruise east, away from the noise of Burlington. Slip south of Highway Two, curving along Hinesburg Road onto Van Slicken Road.  Pass the oldest house in Williston – light grey stones, hand hewn in the 18th century.  Crunch onto the gravel of the parking lot, leave your car (or bike!), and step into the wildness at Muddy Brook Wetland.
Cattails dance on the winter wind, and signs of animals layer this scrubby landscape. To the casual visitor, Williston’s Muddy Brook Wetland rejuvenates and relaxes.  It is a deep breath at the end of the day.
For the budding naturalist equipped with this scavenger hunt, the wetland also offers mid-winter wonder.  Look closely at the ground, the bent grasses, the flowing stream. Find and learn to identify scat, deciduous trees, nests, and other natural treasures. Enjoy!
Find the first scavenger hunt here: Scavenger Hunt- Williston’s Muddy Brook Wetland

Five Bodies

by Danielle Owczarski

I squint as I gaze offshore at the landslide scars jacketing the slopes of the Adirondack Mountains, and become cognizant of the illusion in quiet looking mountaintops, in reality, stark and frigid underneath the winter’s languid sun. I lift the camera to my eye and focus on the lone silhouette of a twisted black willow frozen to the beach, beaten by icy waves. I am in awe of its ability to survive, alone and isolated at the interface of water and earth, defying death.

I am standing on a deserted public beach in Burlington, VT, situated west of the bike path and the Burlington Electric Department. My husband and I, dog in tow and cameras in hand, are in pursuit of stories told by the natural world; those neglected by people behind weatherproofed door jams. During the winter months, protected by the shelter of my apartment, I cannot tune out the arctic breeze whooshing against my door. I imagine the biting wind flowing through my veins, breathing life into my limbs, pushing me to be a part of the world beyond my warm, snug box. Once outside, the indoor fog in my mind lifts and my periphery expands initiating a new awareness. I enter the natural world to feel alive. Continue reading

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