ARBORETUM NEWS (NATURALISTS’ NOTES)
States of Water, States of Mind
SUNDAY, JANUARY 8, 2006The unseasonably warm weather resulted in some rather squishy trails. The abundance of water was actually quite fortuitous since the subject of the hike was Winter Water. I was planning to talk about water in all its forms but was relieved when the warmth held. Melting and refreezing often results in slippery footing. This, in turn, can lead to a much more intimate (and bruising) experience with ice than I cared to provide.
Water is like many things in our lives, when we actually think about it we recognize how important it is but, generally speaking, it is something most of us take for granted. We don’t spend much time considering the properties of water and just how unusual this little molecule is.
Water can be found naturally as a solid, a liquid or a gas. Another odd property water has is that its solid form is less dense than its liquid form. Ice floats. If water behaved like other forms of matter, those dolphin ice cubes would sink to the bottom of a glass of water instead of frolicking at the top. If that fact isn’t alarming, consider that all bodies of water would freeze from the bottom up and, given another property of water, the fact that its takes a lot of energy to change states, these solid lakes would probably never get warm enough to thaw completely. This would not only severely impact lake ecology and the water cycle, it would create complete upheaval in certain parts of the world by eliminating the entire subculture known as ice-fishing. A frightening thought.
Luckily water is an odd molecule. It is H2O, two Hydrogen atoms sharing tiny negatively charged atomic particles called electrons with one Oxygen atom. The Oxygen atom is quite a bit bigger than the Hydrogens and exerts a greater pull on the shared electrons. The water molecule ends up with slight positive charges around the Hydrogens and a slight negative charge around the Oxygen (take a deep breath I’m almost done with the pure science stuff). Due to all the positive and negative charges, weak attractions commonly called Hydrogen bonds form between water molecules. These “bonds” really are just weak attractions not actual chemical bonds, but the end result is that water molecules stick to other water molecules. The hydrogen bonds give water many of its unusual yet important properties, like high surface tension, the ability to “hold” heat and release it when changing states and, of course, the odd nature of solid water.
When atoms are warmer they move faster. Generally speaking, when a bunch of matter cools down, atoms move more slowly and pack together more tightly. As matter cools, it ends up as a solid that is denser than the liquid form was. Water is an exception. The molecules in liquid water move around with enough energy to constantly break and reform the Hydrogen “attractions.” As water cools, the molecules do get closer together. Water is densest right before freezing (at 4 degrees C). As the molecules slow even more, they reach a point where the maximum number of molecules stay hooked together. Because the unlike charges attract yet the like charges repel the molecules become “stuck” in a crystal formation rather than packing closely together. Compared to liquid water, solid water has a more open (crystal lattice) form. This gives us ice and snow.
There were patches of snow to observe, but the majority of it was gone. With the insulating and camouflaging snow sides and tops gone, the tunnels of the voles were not only fully exposed but in danger of becoming submarine instead of sub-nivean. The plentiful tunnels caught the eye of even the casual observer and were good reminders that life continues to thrive even in the midst of winter. It seemed very apropos to read Aldo Leopold’s “January Thaw” essay from A Sand County Almanac. Leopold talks about what snow means to the small mammals and what thaw means to the hungry hawk. Although we didn’t see a hawk on Sunday, I have seen many hunting in the last few weeks. Small mammals are much more vulnerable without snow to hide under. The vegetation does provide some cover although the flattened tough grass of winter isn’t as easy to meander through as the fresh grass of spring. Also, while snow insulates, water flattens fur and feathers making it difficult for animals to keep warm when the temperature drops.
Warmer weather seems to have resulted in more activity among birds. Turkey tracks were plentiful, and we disturbed a male near Teal Pond. Evidently not in the mood to be on display he trotted resolutely off into the underbrush.
Smaller birds were active and vocal also. A downy woodpecker caught our attention as he busily foraged, spiraling around the trunk of a tree by the stone house in Gallistel Woods.
On the wetland boardwalk the absence of snow cover gave us a chance to appreciate the patterns, colors and textures of leaves under the ice.
We had experienced first hand ice, water, and snow on the trail, at Teal Pond, and in the wetlands. But no winter water hike would be complete without a visit to at least a few of Lake Wingra’s springs. Since groundwater is warmer than surface water in the winter, springs provide open water and areas of slightly elevated temperatures. On cold days you have a good chance of finding birds puffed up in the trees and shrubs by the springs. Sunday the weather was warm enough that we found no avians huddled by the springs, but several mallards were cruising out toward the lake.
The riot of watercress growing in the open water seemed especially lush against the background of muted browns. The green of the watercress was complimented by a multitude of vibrant red berries dangling in the underbrush.
I would have been much more appreciative of the berries if they didn’t represent a whole new generation of the incredibly hard to eradicate alien honeysuckle. Unfortunately, refusing to appreciate the natural beauty of their berries has never been cited as a proven method of honeysuckle eradication, and at least we had a reminder of the ubiquitous nature of the honeysuckle and fist hand knowledge of one of the main reasons that certain species can become a problem. They reproduce well.The cold weather will return. There should be plenty of opportunity to appreciate all the forms of water. Visit the pond, and consider all the animals spending the winter in a state of suspended animation, some even frozen solid. Visit the springs, and watch for snow tunnels on the prairie. Look at the sky, and appreciate the water vapor that is being carried by the air. Even if no clouds are present, there is water in the air. We just don’t tend to notice it in smaller quantities.
I enjoy learning new facts about things that surround me every day. Even if I haven’t learned something new, sometimes all it takes to gain a new (or perhaps renewed) appreciation is taking the time for a closer look. There are many things that are essential in our lives whether or not we choose to think about them. Water in all its states, the air we breath, the ground we stand on, the life that grows, soars and scurries and saunters around us and the people that influence us every day.
Take the time to visit the same old places in the Arboretum and bring along one of those same old friends. With the right perspective, I’m sure you’ll have a brand new experience, even if you don’t choose to visualize a water molecule.
Susan Simonson, Naturalist