notageek

Supposedly, since I’ve had a course in microbiology, I know a fair bit about prokaryotic life.

That’s silly. I can juggle redox respiratory half-equations, and I can calculate the number of ATPs phosphoryalted for each molecule of whatever metabolised, and I can talk at length about autotrophy and nitrogen fixation, and a bit about different sorts of pathogens and toxins, but that doesn’t really mean anything.

A Winogradsky column has some cellulosic material at the bottom, buffered with calcium sulfate. The rest of the jar is filled with mud to within an inch of the mouth, topped with water and left in front of a convenient light source. Mine lives in the windowsill. The bottom layer usually turns black; sulfidogenic bacteria eat the cellulose and make hydrogen sulfide. This diffuses upwards to the phototrophic green and purple sulfur bacteria and the green and purple non-sulfur bacteria (which actually do use the hydrogen sulfide). Mine is from the Millrace pond, and appears to also have a lot of iron oxidisers. Iron oxidisers, and similar microbes, are part of the reason strip mines get those acidic buildups. They may also be the reason I don’t have many purple bacteria.

Floating around the top, oblivious to the anaerobic sulfur-based drama below, are some cyanobacteria. They seem pretty happy in their little oxic environment.

I could write you the redox equations for all of those colonies, the change in standard free energy, the ATPs hydrolysed, the bizarre thermicities of some microbial communities, and it would not matter. I know of but do not know these microbes; the Winogradsky column, after all, is named after someone who did both. All I did was put some paper towels and mud into a jar and leave it in the windowsill.

The bacteria appear unchanging. Their jar holds a stable community, a dynamic equilbrium of life unaware of its confinement, a clonal colony of clonal colonies from a pond across town. The microbes sit in my window, and, when I remember, I love them.