Water is Life Part 3: Winter

Note: This program first aired on January 14, 2017.

We’ve been talking lately about the fact that water is life. It plays a critical role in our most fundamental biological processes, without it life could not go on. We’re told to drink water, maybe as much as 8 cups a day, in order to have enough liquid on board to meet our needs. Plants use liquid water too, but water vapor, the gaseous form of water is ultimately what drives water movement from one part of a plant to another. Ice, water in its solid crystalline form, is generally a liability to life. Ice forming in and around cells in living tissue can result in mortal damage to those cells. So yes, water is life, but the ways that water associates with life vary widely.

If you keep house plants or grow a garden, you know that plants need water. Water is an ingredient in the fundamental biological processes of photosynthesis and respiration, both of which plants partake in. When we think of plants that live in severely water deprived environments, our minds go first to the desert. Though there is little water in the desert environment, there are plants adapted to take advantage and maximize the little water that is there. Those adaptations encompass mechanisms to store water when it becomes available, reduction of  the normal water loss that results from metabolic function, and enhanced ability to photosynthesize in high heat. We all know what those plants look like—fleshy, spine covered, leafless cacti. Plants adapted to survive with just barely enough water.

There is another kind of water limiting environment out there, it’s called winter. In winter, water is typically locked up in solid form, unavailable for biological processes. Additionally, the cold air of winter can hold less water vapor, so there is less gaseous water around as well. The plants we see all around us here in the temperate zone reflect a variety of ways to deal with this seasonal water stress, to deal with the fact that water is life, but part of the year they can’t access it.

Plants deal with the inability to get water in winter in many ways. Some just avoid the issue altogether, over wintering as a seed (in the case of annual plants), or underground roots or bulbs. These strategies enable the plant to lie dormant, and suffer no water loss during the time when liquid water is scarce. Others, the deciduous woody plants, shed their leaves, and for good reason. Leaves are the site of water loss in leafy vascular plants. Water moves up through the plant from roots, which gather water from the soil, to the leaves, where water is used in photosynthesis. It isn’t pumped, but rather is pulled. As leave release water vapor, through pores on the underside of leaves called stomata, it creates a vapor pressure gradient. Water exits the leaves, creating a water void that must be filled, and is filled, with water rising through the plant vascular tissue, called xylem to replenish the water lost by the leaves. In the winter, water can’t be gathered by the roots, as the soil moisture is frozen solid, so water can’t move up the plant to replenish the leaves. Additionally, much of the vascular tissue of the plant is frozen, compounding the barrier to water transport. If the plant had broad leaves that continued to lose water vapor through stomata all winter long, there would be no source of water to replenish the leaves. Desiccation would result, and cell death. The shedding of leaves by deciduous trees is a direct response to this water stress. By shutting down all transpiration, deciduous plants reduce winter water loss to a minimum. Trees that don’t lose their leaves in the winter, primarily the conifers in this part of the world, have other ways of minimizing water loss in the winter. The needles of these trees are in fact leaves, but they do not photosynthesize year round. In the heart of winter, the stomata of these leaves are closed shut, and water loss through transpiration drops to a minimum. In addition, the needles are encased in a thick waxy cuticle that is not very permeable to water, another adaptation to minimize water loss that could occur through diffusion of water vapor through a permeable leaf surface.

Water is life, but in winter, even though we often have a lot of precipitation, it is in short supply. Plants show a remarkable diversity of adaptive strategies to deal with this seasonal water stress. We could learn a lot from them.

References:

Peter Marchand’s Life in the Cold: An introduction to winter ecology is a classic in the field. (University of New England Press)

December Darkness

Note: This program first aired on December 20, 2014.

It’s December in Maine, and I know people who hate this time of year, people who struggle with the darkness. People who utter a quiet little curse at the summer solstice when the days start to get imperceptibly shorter, and wail and gnash their teeth out loud at the fall equinox when the balance tips in favor of the night. For them the winter solstice means hitting rock bottom, with only the faintest brightness that from here on out for the next 6 months, the days start getting longer.

I have to admit publically, and I may lose some friends for this, that I love this time of year. I love waking up in the dark, and burrowing in to home and hearth in the late afternoon. I love the long nights and late mornings. The pace of modern life is so mismatched to the natural seasonal rhythms here at the 44^th parallel, we rush off to work in the morning, stay until late afternoon, come home after sun down. Of course the long nights and short days feel untenable. But if you can give your self the mental space to touch base with your inner self, call it your ancestral self, I think you will find, as I have, that these long nights serve a purpose. Your body knows what it is.

As the days grow shorter in the late fall, I have a harder time going out to run. I start thinking about yoga instead, and I restart my meditation practice. I stop eating salad, and instead roast root vegetables by the pan full. I do this because it is what feels right, because I trust the ancestral knowledge in my cells, because my body evolved with seasonal patterns, and the past 150 years of human evolution (or lack thereof) hasn’t erased them.

If you look around the natural world for cues this time of year, every one of them will tell you to settle down, to rest up, to wait. Deciduous trees draw their sap down underground and wait out dry and the cold of winter. Many mammals, reptiles, amphibians, and insects spend this time in a state of suspended animation, living off the bounty of summer, waiting for the next productive season to come. In learning to embrace winter I do not suggest truly hibernating, or hardening yourself against the cold; instead use this time as a resource. Nature bids us inside, and provides us with quiet. Take these moments to rest your self and let your mind settle, these moments are fleeting and rare in our modern lives. One of the reasons we find the holidays so stressful is that we’ve let them become a time of arousal and glitter, parties and over indulgence instead of reflection. Everyone I know who celebrates Christmas tells me the same story; their favorite thing is to sit quietly in their living room looking at the lit up Christmas tree, the rest of the lights off, families asleep. Silent night indeed.  We are seeds, waiting in the frozen soil, we are chipmunks resting in our burrows, we are chickadees flying at day break, we are wood frogs frozen in the leaf litter, we are white tailed deer yarding up in a cedar swamp, we are humans negotiating an increasingly complex world here half way between the equator and the pole.

We’re coming up fast on the Winter Solstice, the moment when the Earth’s axis of rotation points us in the northern hemisphere as directly away from the sun as possible. It will be another 6 weeks or so before we notice that the days are getting longer, at about that time the plants will start to notice too. In the mean time, stoke up the fire, turn off the lights and plug in your Christmas tree, or light a candle or look out at the stars and the moon. Take this dark time for what it is, a gift not a curse. Happy solstice everyone.

References:

http://www.timeanddate.com/calendar/december-solstice.html

Sea Smoke

Note: This program first aired on December 28, 2013.

We’ve had some very cold weather so far this winter, and beyond the obvious experience of stepping out the door on an arctically cold morning, I can tell it is cold when I am driving to work and I see sea smoke on the harbor. Sea smoke is the wispy mist that forms on cold days just above the surface of open water, and when you see that, you know its cold out.

Sea smoke is like fog, it results from the difference in temperature between the air and the water. I wrote about this many years ago on this show, but I think it is time for us to revisit it. The fog we encounter in the summer comes from warm air hitting cold water, or a rapidly cooling landscape. Warm air can hold more water vapor than cold air and when the warm air gets cooled, it can’t hold as much water vapor. The water vapor in the air has to go somewhere, and it condenses out as fog.

What we are really talking about here is relative humidity. Air of any given temperature can hold a certain amount of water molecules in the gaseous phase—water as a true gas. We can’t see water in this phase—its different than steam, or seeing your breath. The maximum amount of water vapor the air can hold at any given temperature is called the saturation point. When air is holding as much water vapor as it can at its given temperature, it is said to be 100% saturated. Its relative humidity is 100%, because, relative to its temperature, it is holding as much water vapor as it can. As air cools down, its relative humidity rises. The amount of water the air may contain doesn’t change, but the ability of the air to hold that water does, when air cools down to a temperature where it is 100% saturated, we call that temperature the dew point. If the air cools below that, liquid water will condense out of the air on any surface it contacts. In the winter when this happens, it forms frost.

Sea smoke is different than the regular summer fog we can see on land and in river valleys as well as on the ocean. In the regular fog scenario, the water vapor is in the warm air mass, and only condenses because the warm air gets cooled when it encounters cold water, or cools as it travels up over a ridge line or pools in a valley. The source of the water vapor in sea smoke is the sea, not the surrounding air mass. Very cold winter air can’t hold very much water. Its relative humidity may be high, but 100% of a tiny amount is still a tiny amount. That is why everything dries out in the winter, your skin, your wood flooring, your shingles, you get the idea. Sea smoke forms when a very cold air mass rests over warmer water, though again, its all relative. The water only has to be warmer than the air. For example, during this recent period of cold, the air temperatures were around zero many mornings; according to real time buoy data water temperatures are in the low 40’s, Fahrenheit. That is much warmer than the air was, but hardly what any of us would call warm.

The warm water warms the air directly above it, on a large scale this is the reason that the immediate coast tends to have milder temperatures in the winter. That slightly warmed up air can hold more water vapor, and water is constantly evaporating from the surface of the ocean. Warm air also rises, so this slightly warmed, more heavily laden with water vapor air rises up into the much colder air around it, where it cools off. When it cools, it can’t hold as much water vapor, and that water vapor must condense out into liquid form, or as often the case with sea smoke, as ice crystals. As the sun rises further and warms the air mass more uniformly, the sea smoke dissipates, so when you see it, you know you are seeing a special and ephemeral combination of elements; here one moment, gone the next. You also know, its cold.

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From a class at the University of Illinois, a nice diagram showing the non linear relationship of temperature and the overall amount of water in the air mixture. http://butane.chem.uiuc.edu/pshapley/GenChem1/L13/1.html

References:

Great old article from the Woods Hole Oceanographic Institute: http://www.icess.ucsb.edu/~norm/steamfog.pdf

Here’s a much better use of your time than Facebook, its real time buoy data from the Northwest Atlantic: http://neracoos.org/realtime_map

Winter Solstice

Note: This program first aired on December 22, 2012.

6:12  am, Friday December 21, 2012. That’s the local time of the occurrence of the winter solstice. Yes, we tend to think of the solstice as a day, but astronomically, it is a moment in time. At that moment, the planes of the earth’s orbit and axis are perpendicular to one another, with one pole pointed towards the sun and one pointed away from the sun as much as possible. On the winter solstice, here in the northern hemisphere, this day will have the longest night of darkness and the shortest day of light of any in our 365 day trip around the sun, simply due to the angle of the axis of earth’s rotation. The sun’s arc in the sky will be at its lowest, and the location of its rise and set will be the furthest south along the horizon. Once we have passed this point in our orbit, the days gradually begin to lengthen (you and the plants won’t notice until at least February), the sun’s rise and set will edge further north along the horizon, and the sun will creep higher in the sky each day, all as we move along the ellipsis and the axis of earth’s rotation slowly moves parallel with the plane of the orbit (this occurs at the equinoxes).

We call the winter solstice the start of the winter season, but plants and animals (and us) have been responding to the drop in temperatures and the decreasing amounts of sunlight for some time now. Starting with the shortening days of late summer and fall, plants begin their period of outward dormancy. Leaves senesce (or die back or fall off) and the living tissue of the plant becomes limited to the roots and perhaps the above ground stalk. This limits the damage the cold and lack of water can do to the plant. Most seeds are fully developed by this time and should be being dispersed throughout the environment. Animals have three ways to deal with the rigors of winter; they can leave or migrate, hibernate or “tough it out”. Again, as early as late August, observant bird watchers can see birds flocking and preparing to leave our area for warmer, lower latitude environments.   When it gets truly cold as winter really begins, many animals enter a state of torpor, with marked drops in metabolic activity. This decreases their physiologic needs, allowing them to wait out the challenging conditions of winter. Hibernation is the most commonly used term for this, but the phenomenon actually encompasses a spectrum of dormant like behaviors. Of course many animals just tough it out, relying on their stores of body fat and whatever food they can find in the winter, to remain fully active..

Humans have been observing the cycles of the natural world for as long as we have been on this planet. And as the natural order draws in and appears to pause at the cold and dark time of the year, humans have created rituals of observance that inscribe these natural patterns on human culture as well. Black Friday not withstanding, many of our holiday traditions throughout the year are based on early pagan celebrations tied directly to the solar cycles of solstice and equinox. Traditions include contemplative rituals that reflect the quiet and dark of the year, and rituals that celebrate the return of the light. So as we enter these last few days of the frantic modern holiday season, take a moment to reflect on where this frenzy of visiting and parties, family time and gift giving came from—our ancestors, who had all the time in the world to watch the path of the sun and the arc of the moon, and who knew this earth with an intimacy we can’t even fathom today. It is my belief that this level of deep deep knowledge is healing, restorative, and as the events of the last week have shown us, we are deeply in need of this. This holiday and solstice season, honor those that have come before us and pause and pay attention, noticing where the sun comes up and where it drops below the horizon. Do this every day and by February, you will be ready as that extra light creeps into your life. Happy Solstice everyone.

References:

Straight from the horse’s mouth: http://www.crh.noaa.gov/ind/print_localdata.php?loc=txtdat&data=seasons.txt

Ask an Astronomer--http://curious.astro.cornell.edu/question.php?number=686

Cute teacher website from the state of Michigan: http://mff.dsisd.net/Environment/WinterAnimals.htm

There is so much great new age info out there on the pagan rituals as they relate to modern holidays and solar cycles. Google it and you’ll find lots of wild and wacky and very interesting reading.

This is the best show I’ve ever heard on the symbolism of solstice and our winter holidays: (spoiler alert: Santa is a Shaman…)
http://archives.weru.org/specials/winter-solstice-special-122310