Life will do anything for energy. On the mid slope trail of Portland's Eastern Promenade the ruddy, oily mess that surrounded me made that abundantly clear. This particular portion looks like the effluent pond of a pre-Clean Water Act chemical plant. In one direction water seeps out of the ground, somewhere between the color of blood and orange finger paint. In another, a rich, rainbow sheen texturizes the look of a shallow pool, bringing to mind the "Dump No Waste, Drains to Lake" stencils that pop up around water bodies. Despite the look, I know better. I've seen similar scenes in Acadia National Park, an area protected and remote enough that dumping just doesn't seem worth it, even for the most villainous human polluters. Bacteria, however, are another story.
When you get hungry, you might grab an apple and chow down. Your body tears apart the weak bonds of the apple's sugars, leaving a soup of carbon, hydrogen and oxygen atoms. These atoms don't like the single life and when your lungs immerse them in a bath of even more oxygen, the hungry oxygen atoms snap up carbon and hydrogen to create your two favorite molecules: Carbon dioxide and water. You might think it's the sugar that gives you the energy, but, really, your energy comes from building the strong bonds in the compounds you exhale.
The polluters on the East End work the same way: they take up weakly bonded or unbonded atoms and snap them into strong bonds to create energy. Of course their chemical soup is completely different than yours and mine. Instead of carbons and hydrogens, they take up the fourth most common element in the Earth's crust: iron. Like carbon and hydrogen, iron isn't a big fan of going it alone, but deep underground there isn't much of a selection of partners. But, as ground water flows to the surface, it drags with it lonely iron ions, inviting them to a chemical party that they wouldn't have had access to in the subterranean world. Up here, oxygen is a near perfect mate. The bacteria are the E-Harmony of the chemical world, speeding up the matchmaking process and reaping the energy benefits when sparks fly. When oxygen joins with iron, the strong bonds snapping shut powers the life of the bacteria. Like you and I exhale carbon dioxide and water, bacteria pumps out these red-orange iron oxygen compounds, called iron oxides.
That explains the red seeps, but what about the oil on the water's surface? It's worth thinking about what oil is. Generally, oil is the leftover parts of simple organisms that lived a long time ago. In a way, the oily sheen is donated by a material not too different than the fossil fuel. Bacteria, including those that metabolize iron, have a short lifespan. The creation of iron oxides provides the energy needed to power more and more of this simple life form. When members of the community die, their parts float on the surface. The surface film of broken up bacteria creates the same rainbow effect as their prehistoric counterparts that form petroleum.
These iron bacteria may have an impact on our visual environment. But it's not fair to call them polluters. They're just trying to live the same way they have for almost a billion years. To do that means eating, breathing and dying, just like you and me.
Clark, M. S. (2015, October 16). What is Oil? Retrieved April 16, 2016, from http://www.sjvgeology.org/oil/oil.html
Ilbert, M., & Bonnefoy, V. (2013). Insight into the evolution of the iron oxidation pathways. Biochimica Et Biophysica Acta (BBA) - Bioenergetics, 1827(2), 161-175. doi:10.1016/j.bbabio.2012.10.001
Wartinbee, D. (2010, March 24). Science of the Seasons: Yellow boy bacteria has people seeing red. Retrieved April 16, 2016, from https://redoubtreporter.wordpress.com/2010/03/24/science-of-the-seasons-yellow-boy-bacteria-has-people-seeing-red/