Tag Archives: winter

Winter’s sculpture garden

Seven inches of snow, soft as a cottontail, came to Williamsburg and gently closed all the roads, schools, and businesses. The snow was too dry to turn my yard into a gallery of lopsided snowpeople, so I took the time to enjoy winter’s artwork.

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The winter sculptress

January 2015, Eastern Virginia

Ice covered marsh elder - Yorktown, VA, Jan 2015 (1)

The icy fog of winter swallows the Mid-Atlantic. The temperatures drop below freezing and weld the fog to all that it touches. Everything – limbs, leaves, porch steps, 1999 Honda Civics – are glazed with an 1/8 inch rime. Were I snail and one who could skate, I would don my snail sweater and skate (having only the one foot) and invite all my snail-skating gastropod-friends to my front steps and glide from one rail to another. Limbs sag heavy under the new weight. I – not wanting to skate on my steps – grab the rail. It too is slick with the icy slobber of a winter fog – and hold both my breath and myself as best I can. Winter redeems itself as an artist – the world now a garden of ice sculptures.

I scrape ice from my windshield with an bottle because apparently owning an ice scraper is much too much of a luxury. THe holes I make in the ice likely are not street legal as most of my view still obscured, but I take my chances and drive of to admire winter’s artistry.

Ice covered marsh elder - Yorktown, VA, Jan 2015 (3)

Of course I stop in the marsh. That is what you do when every surface you touch is lacquered with ice. Here in Virginia the Spartina stems – though dulled and browned with age – still stand. Today they glisten. Each leaf, each stem encased in a crystalline sheath. One that is cracked like, but intact. Like a mosaic of glass pebbles – each magnifying the beauty of which it clings. On the bushy marsh elder, each leaf is a glassy pendant.

Ice-covered Spartina - Yorktown, VA, Jan 2015 (2)

Ice covered marsh elder - Yorktown, VA, Jan 2015 (3)

My hands, without any sheath – glove or ice or otherwise – beg me back to the car. From the comfort of a defroster I admire what is now an icy meadow of marsh. By the weekend, the 50 degree temperatures will strip away the artistry of winter, each glassy sculpture losing its luster yielding to the rough concrete texture of winter’s true self.

To freeze or not to freeze?

Newbury, Massachusetts The Great Marsh

Coffee-bean snail and wolf spider, Newbury, Massachusetts
Coffee-bean snail and wolf spider, Newbury, Massachusetts (don’t ask me why the colors look the way they do).
Thin-legged wolf spider, Pardosa littoralis, Newbury, Massachusetts
Thin-legged wolf spider, Pardosa littoralis, Newbury, Massachusetts

I had to close my eyes to the spray of ice as I slammed the claw hammer into the 3-inch ice that armored the marsh.  I use the claw to peel back ice chunks and hunt for life.  Ten minutes later I find two winter denizens of the Great Marsh.  I de-glove and carefully remove a thin-legged wolf spider (Pardosa littoralis) and a coffee-bean snail (Melampus bidentatus) from the grass stems.  They are not dead, but possibly as near as you can get.  Their organs are slowed, their metabolism at a glacial crawl.  They are, for now, frozen in time.  One of them quite literally (and I mean ‘literally’, not ‘figuratively’). All overwintering animals, including you and me and your little brother, have two choices when it comes to surviving the winter.  Freeze avoidance or Freeze tolerance.  Freeze avoidance usually means finding a shelter for the winter (called a hibernaculum) such as a burrow below the frost line or a shelter with a thermostat cranked to 72 F and stocked Rolos and oatmeal chocolate chip cookies (no.  not raisins.  raisins belong in only two places:  bran and the trash).  Freeze tolerance usually means that you’ve got to freeze some-to-most of your body.  Some frogs and salamanders and many intertidal molluscs (snails, clams) do this.

The coffee-bean snail shivered so I gave him some coffee.  He took a sip and looked up at me, "Wait, what is this made of?"
The coffee-bean snail shivered so I gave him some coffee. He took a sip and looked up at me, “Wait, what is this made of?”
Coffee bean snail on Dunkin Donuts cup
I will avenge you my brothers and destroy the Evil Empire!!!!! Your slow-roasted deaths shall not be in vain!

But what’s wrong with freezing?  The biggest issue with freezing has to do with ice crystals that form and ice that expands.  Ice crystals are assassins that form inside the cell and use their stiletto-sharp crystals to rupture and kill cells.  So whether you’re a freeze avoider or a freeze tolerator, your imperative is to protect your cells.  Too many dead cells equals one dead you.   Both the snail and spider are freeze avoiders in terms of their behavior:  in the winter they are ‘snuggled’ together under grass clumps that are slightly warmer than the surrounding air.  In terms of their internal physiology, the snail is a freeze tolerator and the spider is a freeze avoider.

Avoiding the freeze
Many insects and spiders (not all) produce anti-freeze compounds (some insects actually produce the same anti-freeze we use in our cars, ethelyene glycol), which lowers the freezing point of their body fluids.   At the same time, they will dump sugars into their body fluids which also lowers the freezing point (anytime you dump sugars or salts into water, it lowers it’s freezing point).  So when it’s 18 F, the spider still won’t freeze though freshwater will.  If I hold this spider in my hand long enough or bring him inside, he will eventually start crawling around (though he’ll be really confused and very hungry).    

Tolerating the freeze
The snail actually freezes part of the body to save the rest.  Part of the fluid outside of the cell (extracellular fluid) freezes which forces body salts into the liquid part of the extracellular fluid.  This creates an osmotic gradient with higher salt content outside of the cell versus inside the cell.  Because Nature seeks balance, the water inside the cell moves out of the cell until the salt levels are equal in and out of the cell.  This cell dehydration then increases the salt content of the cell, which in turn lowers the freezing point of the cell.  Again, saltier or sugarier solutions have lower freezing points  than freshwater solutions.

Wood frogs (Rana sylvatica) perform a similar feat and people have claimed to have found ‘frog-sicles’ under logs.  The take-home is that the frog, just like the snail, is not completely frozen.  It can’t be or it would die.  It may, however, be mostly frozen (up to 65% of it’s body liquid) to protect the cells.  Most of the cells inside are not frozen despite that fact that the soft bodies of snail and the frog are now hard as rocks.

In both freezing strategies, animals are trying to protect their cells and do so by lowering the freezing point of some portion of their body.

We humans do something similar so we can salt icy roads.  The salt melts the ice because it’s lowering the freezing point of water.  The first guy to do this probably thought he was pretty clever.  The coffee-bean snail would shake his head and say, “no, no you’re not.  i’ve been doing it for millenia.”  Then the clever guy would say, “Holy crap!  A talking snail!”

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Thanks to Duley for spending more time than either of us should have trying to craft the perfect snail jokes.   And perfect they are!