Biofilm Festival in Big Basin State Park

Currently, in Big Basin State Park, the reservation-only parking lot is covered with a substance that looks like an oily sheen, and has a "sulfur-like" smell in some areas.

Visitors have shared their thoughts about the smell, and many think it's a human-made event (like leakage from an old septic tank, etc.).
​
What is it? What are its characteristics? What does it remind us of?  Staff are currently gathering observations. Uncovering a mystery is always exciting, and challenges one's assumptions, and patience.
 

Here's what we know:

1. Water bubbles out from underground at the interface of crushed rock/soil and the edge of the parking lot asphalt. The entire portion of this lot is covered with "slime."  Video of parking lot
2. It has been observed during the rainy season, and dries up in early summer into early fall.
3. It breaks apart like glass if you poke it with a stick. (Oil doesn't do this.) 
4. In sunshine, it displays a rainbow-like sheen.
5. Many areas appear to have an orange-rusty appearance. (Iron?)
6. Some areas have a sulfur-like smell. (Bacteria-eating iron?)
7. We're not sure this occurred before the 2020 CZU Lightning Complex Fire.  All structures in this vicinity were burned, and the parking lot is new.

---

Many areas display a white-ish sediment. Soil particles?

Rainbow sheen on the segmented pieces.

According to Justine Dees, a PhD in microbiology, bacteria living in water or sediments can change the form of metals like iron, manganese, and copper. 1 Some bacteria can change iron from a solid to dissolved, and back to solid again. Crazy, right?! Some bacteria ferment while growing…thus the stink!" "Microbial diversity also responds to changes in environmental variables, such as sun, temperature, and location." 2

The image below shows the shiny rainbow colors. If this is biofilm, it meets the characteristics of floating on top and ‘shattering' like glass when disturbed.  Stay tuned. The mystery of the post-fire, redwood forest, with a slimy parking lot, has yet to be uncovered!