On May 28th, community representatives from Ecuador and Nigeria are traveling to San Ramon, California along with Bay Area activists to demonstrate at the gates of Chevron corporate headquarters during their annual shareholder meeting. Supportive shareholders inside will confront Chevron executives about the toxic legacy of oil extraction in the Ecuadorian Amazon. The Nigerian delta has also faced similarly serious health and ecological consequences as a result of oil development.
As for news on the fungal front, I am quite happy to write that our second attempt at mycoremediation in the Amazon has quite literally born fruit. Three weeks after we set up our experiment, a number of the boxes have begun to fruit mushrooms—directly out of the petroleum-saturated layer. We put yellow plastic screens directly on top of the contamination layer for easy monitoring. When we need to take a sample, we can simply lift the screen and get down to the area of interest. The screens also have the benefit of providing a clear visual marker for locating the oil layer.
Multiple clusters of little mushroom primordia (baby mushrooms!) were poking out everywhere from fuzzy-white mycelium. In many boxes, the overall effect was a graying of the black, oil-soaked sections as a result of dense mycelial growth. Every single box currently has healthy mycelium growing inside the contaminated layers, even in our most concentrated treatments, such as the one pictured.
There are no mushrooms fruiting in the large pits we dug and filled with spawn, sawdust and other mushroom substrates. However, the lack of fruit bodies is really not important, since the vegetative state of the mushrooms, the mycelium, is what does the majority of the heavy-lifting in remediation. By use of the yellow screens we were able to peer under several feet of piled spawn and substrate and confirm the presence of mycelium in our pits as well. These fine threads of fungi branch and grow densely through soil and substrate, excreting oil-digesting enzymes along the way.
Visualizing the growth processes in action here is an exercise in pretending to be very small. If I was roughly the size of a cell, the span of a centimeter or two is quite daunting. This is the scale that mycelium operates on. Our mycelium responded to a similar distance created by the plastic screens by sending down ropey rhizoids, root-like fungal structures used for entering a substrate. We can assume that the fungus produced rhizoids because it recognizes petroleum as a tasty meal and is willing to expend metabolic energy to reach (pictured).
In some of our pits, we encountered some weedy fungi that rapidly fruited and died. Despite this, directly under these mushrooms was healthy, almond-scented oyster mushroom mycelium. As such, it seems that our oyster mushrooms are able to hold their own against the first round of competition.
In the following weeks we will be taking samples for laboratory analysis to get a quantitative picture of exactly how much hydrocarbon pollution has actually been digested. Qualitatively speaking, our progress thus far has met and exceeded all of our highest expectations.