In footage shot in 1993, Lynn Margulis visited the bacterial mats of Delta de Ebro, Spain and proceeded to take a piece of slime out of shallow water. This piece of slime may seem disgusting or repulsive, or quite inconsequential, but Margulis believes that this slime, runs our planet. She proceeds to explain that in the Archaean there was nothing but such anaerobic bacterial ecosystems everywhere on Earth. She calls the slime “the tissue of Gaia.”
Lynn Margulis showing the carpet of bacteria in the documentary, “Symbiotic Earth”
For most of the 20th century, bacteria were considered the enemy, the thing that humankind is in constant battle with. We fight bacterial infections and avoid it like the plague. At that point in time, bacteria was only associated with disease. Lynn was one of the first scientists to debunk this popular notion. Margulis pointed out that we are each 10% dry weight bacteria and that we need the bacteria.
The strings that hold that same seemingly repulsive bacterial mat together, contains hundreds of microscopic filamentous cyanobacteria. Cyanobacteria are the first organisms that were able to photosynthesise, using light energy from the sun to convert carbon dioxide and water into oxygen and glucose. Margulis believed that these bacteria represent the highest level of evolution because they were able to live off just carbon dioxide, sunlight, and water.
We know that for animals and plants alike, extinction always remains an unfortunate possibility. However, Margulis was known for her opinion that bacteria are exempt from extinction. Margulis reasons that this is because bacteria continuously transfer their genes back and forth via genetic recombination. By continuously exchanging their DNA, bacteria permanently acquires genetic material from other very different types of bacteria with no regard for species barriers. Bacteria hence, do not have distinct and discrete species. In this regard, all bacteria can be, and according to Margulis, should be considered as one planetary organism.
In addition, Margulis postulates that the unit of life is bacteria. Bacteria are community-forming organisms and therefore form interrelated communities such as the bacterial mats, and even new kinds of communities that we are familiar with– the communities which we recognise as plants, animals, fungi, and protoctists. As a result, Margulis posits that bacteria formed all life on earth. They were here long before we got here and they will be here long after we are gone.
“They run the planet, “ Margulis says. Truly, bacteria run our planet and it was Margulis who saw our planet’s dependency on them, thereby highlighting the need to ensure their protection and appreciation. Her work in bacteria contributed greatly to the scientific community’s interest in these microorganisms.