Friday, August 25, 2017

The Channels of Bark Bay Slough

We could not have asked for a more perfect morning. The black, tannin-stained waters of the Bark Bay Slough were perfectly calm under a warming sun as we launched my trusty Old Town Penobscot 16 canoe from the dock. We paddled easily, blissfully, into the morning, savoring the magic of floating through a beautiful place.

Bark Bay opens to the northeast, and nestles between two ridges of erosion-resistant sandstone on the western face of the Bayfield Peninsula near Herbster. It is the estuary of the Bark River, and the back of the bay is almost entirely cut off from Lake Superior by a giant sandbar. Boggy little islands dot the enclosed slough—each with their own arrangement of weather-sculpted bonsai trees. Exhibiting both scrappiness and grace, the stunted white pines, black spruces, and tamaracks twist toward the sky. Around their bases crowd thickets of leatherleaf and sweet gale dotted with wild roses.

As my cousin Alyssa and I paddled slowly eastward through the island maze, mats of bog and fen vegetation crept out from the shore and narrowed our passageways. We never knew if our next turn would bring us to a cul-de-sac or a channel. That slight element of mystery was delightfully thrilling, and brought back memories of playing pretend with Alyssa in my grandpa’s shrubbery. Add to that a shy painted turtle just poking his head out from under a water lily leaf, and we were completely entertained. I don’t often have a day where my curiosities so perfectly match that of my adventure buddy. On this day, I savored every breath.

Following our interest, and beckoned by their beauty, we spent at least ten minutes in a patch of water shield, Brasenia schreberi. The palm-sized oval leaves of this aquatic plant float on the surface of calm waters. A thin, flexible stem attaches to the middle of each leaf’s underside and tethers it to a horizontal stem that runs along the muddy bottom. Clear, slippery jelly coats the undersides of the leaves and protects them from grazing snails and harmful microbes. When it grows in thick patches, which is often, water shield creates a spectacular mosaic of color, especially in late summer when brilliant bursts of red and yellow paint the dying leaves.

Other patterns add interest to a patch of water shield, too. Most of the glossy leaves are riddled with holes or dissected by squiqqly lines, which all look black against the tannin-stained water.

What would make those marks? And was it still around? One by one, I held a few different leaves up to the sun, and tried to capture this living example of stained-glass beauty. To my surprise, these trails differed from other leaf mines I’ve seen. Leaf miners are a group of insects (including moths, sawflies, flies, and beetles) whose larvae feed on the insides of a leaf between its “skins.” These weren’t mines, though they were channels, in some cases now worn clear through the leaf, with only a few of the tougher veins keeping the sides of the seam from ripping apart.

Another, more subtle difference, was that although not all the trails were the same thickness, each trail was the same width from beginning to end. What I’ve enjoyed about most other leaf mines is that they start small and get bigger, allowing me to imagine the little larvae growing up.

Perhaps the only person who’s really investigated the origin of water shield’s leaf marks was a fisheries biologist named Adelbert L. Leathers in 1922. From his writing, I learned that the squiggles are actually channels and not mines. In a mine, the larva burrows between the upper and lower skins of the leaf, eating the innards, but leaving both of the outer layers intact. In contrast, these channels in the water shield are created by removing the upper epidermis entirely.

With weak mouthparts, the midge larva Polypedilum braseniae, cuts off a strip of the epidermis, scrapes it clean of nutritious green cells, and then uses silk to fasten the strip into a roof above its channel. This setup allows water to continuously flood the channel. The larvae breathe through blood gills and will die if they dry out. Even submerging too deeply will kill the larvae, presumably because they need the super-oxygenated water you find near the surface and in contact with living plant cells.

Mr. Leathers watched as green plant cells moved through the digestive tract of the pale yellow larvae. He noticed that when the food exits the other end as frass (poop), it’s still useful. The larva places frass where it can help hold a strip of epidermis to make it easier to scrape, and it eventually becomes part of the channel roof. After seven to ten days, the larva spins a silken pupal case and metamorphoses into a tiny midge with shimmering wings and an ethereal green abdomen.

Still, much mystery remains. Although Mr. Leathers was able to find the midge’s eggs on submerged water lily leaves and successfully hatch them, he could not get the tiny larvae to grow or survive. They only arrive at the water shield leaves to begin channeling after they are mid-way through their larvalhood. The strength it takes to cut through the epidermis limits the size of larvae that can make a channel, and the larvae would rather start in an old channel and branch off than go to the work of sawing through fresh material.

I love discovering that there are unsolved mysteries in science. When I start investigating something new to me, I never know if my next question will open up to a cul-de-sac or a clear channel. That element of mystery means that observing nature is always delightfully thrilling.

Special Note: Emily’s book, Natural Connections: Exploring Northwoods Nature through Science and Your Senses is here! Order your copy at  Listen to the podcast at!

For 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. Come visit us in Cable, WI! Our new exhibit: "Better Together--Celebrating a Natural Community" is now open!

Friday, August 11, 2017

Watching the Clouds with Lois Nestel

July was a whirlwind, and now that August is here, September feels just around the corner. It’s times like this, especially, when reading an old article from Lois Nestel feels like a deep, calming breath and a much-needed antidote to our modern pace. As the founding Naturalist and Director of the Museum, she brought a special aura of patience, calm, and quiet joy to anyone who stopped by the Museum to ask a question or share excitement about a natural phenomenon.

So today I encourage you—and myself—to pause for a moment and enjoy something summery, stand in awe of nature, or maybe just spend some time looking up at the sky.

Lois wrote: “I wonder – does anyone watch clouds anymore, just for the sake of cloud watching? To me, these are some of nature’s most beautiful formations, never twice the same, always amazing, whether puffy fleeces, shredded mare’s tails, or threatening banks jeweled with lightning.

“In the habit formed in childhood I still see in the cumulous clouds a fantasy world; human faces and forms, animals, landscapes, ever-changing and reforming, sometimes in such majesty that it seems that I must glimpse the face of God.

“Sunrise and sunset add a new dimension to cloud formations, adding tints and strengthening contracts. The towering castles and turrets of thunderheads in an evening sky overwhelm one with awe as the high-piled vapors glow with snowy whiteness tipped with crimson, rose and gold and shades too evanescent and fragile to describe. Small wonder that artists have depicted angels sailing along on heavenly cloud ships in a blue, blue sky.

“It is satisfying, I suppose, to name the clouds scientifically – stratus, cumulus, cirrus, cumulonimbus—but to really see the clouds, to know their beauty and their meaning has far greater satisfactions. A mackerel sky at evening means more to me than to identify alto cumulus clouds, and the fat dumpling wind clouds, the slatey snow clouds, the boiling masses of summer storm clouds are familiar friends who need no names.

“Lift up your eyes, not to look for storm and trouble but to see the magnificence that fills the sky. Rejoice that such beauty, such grace is free to all. Look and you, too, may see the face of God.”
Lois also wrote of another type of shimmering cloud, a phenomenon I’ve only read about. Have you been lucky enough to see this, too?

She wrote: “I have been witnessing the flight of the queens, a shimmering, living column rising from the ground, funneling out and dispersing to the four winds.

“One warm evening, in seemingly spontaneous impulse, the ants poured forth from every hill; tiny red workers, the males and the queens, covered the earth for yards around in a seething mass of life. There was no flight then, just incessant, restless movement—a preparation, an anticipation of things to come.

“As darkness came they were forgotten, but with the rising sun the flight began. Gossamer wings flashed jewel tones as they rose—fountain like—high into the morning sky. In unbelievable numbers they rose for an hour or more, not just from one source but several within sight. How many more unseen nests spewed out this shining geyser of life is impossible to imagine.

“Before and all during the flight the little, wingless worker ants scurried about as though preparing the winged males and females for their nuptial journey. Back and forth through the winged throng, still earthbound, they moved, stroking a wing here, an antenna there, doing what duties one can only guess. Almost unseen among the larger royalty they moved swiftly and with seeming purpose. As the flight neared its end the workers appeared to round up the stragglers and send them on their way. Suddenly the winged ones were gone and almost as abruptly the workers vanished underground; the lifeless-looking mounds of sand were all that remained in view.

“Somewhere the matings occurred and the males died. The queens cut off their glistening wings and, having had their one brief interlude in sunlight and sky, now dug into the dark earth to live, to propagate, to die. Duty is instinctive. No longings, no regrets becloud their lives. We reach the heights of joy and the depths of despair. We rage of duty and regimentation. We destroy ourselves. The ants, serene and organized, go on. Who are the civilized?

Special Note: Emily’s book, Natural Connections: Exploring Northwoods Nature through Science and Your Senses is here! Order your copy at  Listen to the podcast at!

For 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. Come visit us in Cable, WI! Our new exhibit: "Better Together--Celebrating a Natural Community" is now open!

Friday, August 4, 2017

Forest Bathing

Through the soles of our feet we experienced the transition from gravel drive onto leafy duff. Conversation faded as we entered the forest on a faint path and then formed a circle in a natural foyer surrounded by slender saplings. Fourteen women stood quietly while I pulled the book Swan, by Mary Oliver, out of my satchel. Above us, maple leaves glowed against a gray sky still lingering after a midnight rain.

My finger found the bookmark I’d placed earlier, the pages opened wide, and I began to read the poem aloud. “What can I say?...The song you heard singing in the leaf when you were a child is singing still...” As the last poem concluded, a gust sent a crescendo through the canopy.

We closed our eyes and inhaled deeply, feeling the goodness of air as it filled our lungs. As cool sensation rushed in, we imagined all the previous lives that the carbon, oxygen, and nitrogen molecules had made possible. Returning our breath to the world, we sent our carbon back out into the forest to fuel new life. Giving. Receiving. Giving. Receiving. The breeze swirled all of our exhalations together and carried them off through the trees.

More than just simple air flowed into our lungs, though. All around us, nature was giving off an array of chemicals. These phytoncides include a bouquet of volatile organic compounds released by plants. Their main purpose—from the plant’s perspective—is to prevent it from being eaten, infected, or decomposed. Appropriately, the word phytoncide means “exterminated by the plant.” These toxins are categorized as secondary metabolites, or chemicals that aren’t essential for normal growth and reproduction, but which often help the plant survive in other ways. The strong smells and health benefits of onion and garlic are derived at least in part from phytoncides. While all plants have some, tea tree, oak, cedar, locust, and pines are known for having high levels of these helpful compounds.

In order for the plant to prevent damage to its tissues from too high a concentration of its own toxins, it has to have a way to excrete the excess and maintain balance. Some may escape to the air when pores open to let in carbon dioxide. Others may leach out and flow away with rainwater. Still more are released as the forest duff decomposes. However it happens, these phytoncides become part of the forest at large, and we breathe them in.

It’s a wonderful gift. Not only do the antibacterial and antifungal properties of phytoncides help plants fight disease, they also stimulate our human bodies to increase the number and activity of cancer- and virus-fighting white blood cells (also called natural killer cells), and to decrease the concentration of stress hormones.

That breathing deeply in a forest is good for you comes as no surprise to most people. Anyone lucky enough to live near the woods and smart enough to take time to enjoy them feels the benefits.

When I tell people that it has a name, though, they usually think I’m kidding. The Japanese Ministry of Agriculture, Forestry and Fisheries wasn’t joking, however, when in 1982 they coined the term “shinrin-yoku,” which translates roughly to “forest bathing.” In a country where they have a special word for “death by overwork,” this stress-reducing preventative medicine has become extremely popular. On official forest bathing trails, visitors regularly submit to measurements of blood pressure and stress hormones as researchers gather data. Psychological research reveals that forest bathing reduces anxiety, depression, anger, confusion, and fatigue while boosting cognition, focus, and empathy.

It’s not just the phytoncides. According to scientists, the air in forests and near water has relatively high levels of negative ions, which are purported to boost our mental outlook. Also, simply looking at trees is good for us. And then there are the bacteria.

Having healthy gut bacteria is emerging as a significant factor in our mental well-being.  In another example, inhaling the common soil bacterium–Mycobacterium vaccae has been shown to increase serotonin levels in the brains of mice. Not only does this “happy chemical” decrease anxiety, it also makes the mice smarter!  Mice given the bacteria navigated a maze twice as fast as the control mice. The effects do not last long, though, and scientists surmise that humans would need to be exposed about once a week in order to reap the benefits of these healthy bacteria.

That’s fine with me. It was lovely to walk among the regal hemlocks of Fairyland State Natural Area as patches of blue sky peeked in from above. We offered words of gratitude. I saw the lines on peoples’ forehead soften. Peaceful smiles glowed. While I read the poem “Black Swallowtail,” by Mary Oliver, I thought about how appropriate its metaphor was to our walk. The “interesting, but not exactly lovely” caterpillar busies itself with eating. Only after becoming a still, quiet chrysalis with “faith and patience” is it able to “express itself into the most beautiful thing.”

Above us, the leaves sang.

Special Note: Emily’s book, Natural Connections: Exploring Northwoods Nature through Science and Your Senses is here! Order your copy at  Listen to the podcast at!

For 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. Come visit us in Cable, WI! Our new exhibit: "Better Together--Celebrating a Natural Community" is now open!