I spend my work days wondering about the ways of microbes, bacteria actually. Things that most people think of in only one word, germs, and in one way, they make you sick. Oh yeah, and they are gross and icky. Of course, its true that some bacteria can make you sick, indeed they can be dispassionate killers; they have been doing it for the entire time we have been human beings, which I think is the reason they naturally scare us. But the vast majority, and it is nearly impossible to convey exactly how vast a number, vast is, are benign or beneficial. So here are some fun microbe facts.
Microbes as generally defined are bacteria (actually bacteria are way more than bacteria but maybe that will be the subject for another day), viruses, fungi, single celled algae and protozoa. You need a microscope to see them. Their diversity is amazing. Take a look at a broad oak tree growing in a field and imagine that it is the family tree of all life on Earth. It would be two or three of the smaller limbs growing at the top that would represent the tree itself and all living plants and animals that we can easily see. The trunk and all the other branches represent microbes. Imagine further that the tree represented the entire history of life on Earth. Again just the uppermost branches would represent the amount of time in the tree’s life that animals and plants have been present; all the rest would be microbes. And finally you could take the mass or weight of the tree, again only a few medium size limbs would represent the weight of all multicellular life that has lived on Earth, and microbes would be the rest.
Microbes, principally algae, invented photosynthesis long before the land plants that grow so abundantly in Maine. The oxygen in one out of every two breaths of air we breath is produced by microscopic algae living in the ocean. One of my colleagues at Bigelow Laboratory calculated that if you could take all the single celled algae in the world’s oceans and compress them into 2 inch x 8 inch plank, it would reach from the Earth to Moon. What’s really amazing is that all those algae are growing and in a day produce enough new cells to make a second plank the same size; however this plank is consumed by predators, who are consumed by predators, and so on, until you have made all the fish in the sea.
Over 95 percent of the cells in our bodies are bacterial cells and not human cells. It is estimated that there are thousands of microbial species and that they form unique ecosystems depending upon whether they live on our skin or in our mouths or digestive tracts. We are only beginning to learn what they are all doing, and how we benefit from having them. One of their functions is almost certainly to prevent infection by harmful or pathogenic microbes.
Bacteria are the only organisms on the planet that can capture nitrogen out of the air and convert it to protein. The ones I study eat metal. Microbes hold the temperature record for life, growing at a scalding 222° Fahrenheit at a deep-sea vent. They can grow in sea ice at -5° F. Most of the natural gas we use was produced by microbes. Some live in concentrated acids and others live in alkali lakes. They are life at it’s most resilient, resistant, persistent, and tireless.
So the next time you take a breath, eat a steak or tofu burger, or pass gas, thank a microbe.