By Greg Lecker
The windy, gray day passes a rumor of clearing and sun. As I walk along the path on the south side of Green Heron Pond, a red squirrel chatters at me. A chipmunk – or ground squirrel – darts across the path and dives into its burrow.
Front Door for a Chipmunk
I walk around Green Heron Pond to the boardwalk to study the bog. Grasses have dried and faded to a tan border that casts a dark shadowy reflection into mysteriously colored mirror.
Reflecting on a Gray Day
Below the surface of a purple gray watery surface lies an unseen world of mystery and wonder!
One of the advantages of my recent artist residency was to work with St. Croix Watershed researchers who study water and ecosystems around the world – including the water in the bog of Green Heron Pond. During a laboratory visit, I was shown a slide mount of a sample taken from such water. Some areas on the slide were circled with small red circles maybe a few millimeters or an eighth of an inch. Those were the areas we were going to examine with the aid of a powerful microscope. Looking down the axis of such magnification requires a steady gaze – and photography requires a still hand on one’s cell phone. After about ten attempts I was able to capture one clear image.
Diatoms are a group of microscopic algae found in fresh and saltwater, soils, and even between ice crystals. The word “diatom” literally means “cut in half”; and that describes a basic characteristic of its symmetrical shape. Specifically, its symmetry is “bilateral”, meaning that the top and bottom halves – or the left and right halves are mirror images. Some species are also radially symmetrical – meaning that their circular or star shape can be cut into equal and matching pie-shaped slices. Diatoms reproduce by dividing into two parts.
Diatoms are studied to monitor environmental conditions – commonly water quality. Diatomaceous earth is useful in water filtration, in cat litter, and as a mild abrasive. Gardeners may have heard of diatomaceous earth as its abrasive edges can be used to deter slugs.
Diatoms can be found as solitary cells or as clusters called colonies. Their cell wall is made of silica – and it can be exquisitely detailed.
Water – both still, and moving – fascinates me! I studied the waterfall behind Snyder Building over several weeks this summer while painting a canvas. I watched the rocks dry from morning dew; and I noticed that water flow would change from day to day. Even the amount of algae on the rocks would vary. Most challenging was the changing light. Low angle sunlight in the early morning allowed fleeting glances below the surface of the water.
Visit the Cafe Gallery to see works by my fellow artists who have been painting on location (“plein air”) during July, August and September, 2018. Artists will be in the gallery Saturday, November 10, between 10 a.m. and 2 p.m. to answer your questions.
Greg Lecker is a Minnesota Master Naturalist Volunteer.