Last week I visited Vasquez Rocks, and wrote about the trip in this post. While the geological features were neat, what really interested me were the critters growing on the rocks. After all, what organismal biologist can go to a park with the word “rocks” in the name and not look for lichen?
For those who don’t remember Bio 101, lichen are a symbiotic organism: they’re a fungus and either a green alga or cyanobacterium living as a single unit. Fungi are masters of living in dry, dessicated environments with low nutrients (many plants have fungal symbionts that help the plant’s roots get nutrients out of the soil). However, fungi can’t obtain energy from sunlight. Luckily for lichen, algae and cyanobacteria are photosynthesis experts. Pair the two up and you’ve got an amazing organism: one that can survive in a desert, exposed to the full summer sun all day while living on nothing but bare rock. No soil to get nutrients out of. No possibility to send roots down to the water table. They’re awesome.
But from far away, lichen don’t look like much1 . After all, many species of lichen require years to grow a centimeter or two (growth rates of lichen are typically reported as mm/year). But look up close, and the beauty of these organisms reveals itself as a complexly structured body consisting of beautiful lines, textures, and colors.
Quick quiz: how many species of lichen are visible in that picture?
The gray one that fills the frame is the dominant individual, but there’s at least four species visible2. And the gray one is overgrowing all the other three. This is competition, lichen style. Lichen have only a limited amount of area where they can grow (the surface of some substrate), and inevitably they start to run into each other. Since they get their energy from light, whoever can overgrow the other is likely to win. You’re witnessing a fight to the death.
The number of lichen visible in that picture also demonstrates another characteristic of lichen that I love: they’re diverse. Walk into any given habitat that’s amenable to lichen, and within a few feet you’ll likely find a dozen or more different species. They’ll be different colors, textures, shapes, and sizes. See, for instance:
Most lichen are ascomycetes, meaning that their fruiting bodies are based around asci, which are often found in cup-shaped structures. Take a look at the picture above, and you’ll see a couple of little cups; these are their apothecia, and they’re filled with spores that will be released into the air to grow into new lichen.
Adding to the diversity of lichen is the range of sizes they come in. Compared to the two above, the ones below are growing as tiny individual units:
Vasquez Rocks were featured prominently in the Star Trek episode “Arena” 1. The formation seen above is on the left-hand side of the classic shot of Kirk facing off with the alien Gorn; scroll down on this page to see the classic Star Trek shot2.
The rocks are indeed visually interesting, and I wish we’d had more time to explore them. I got distracted by all the beautiful lichen present (which will the feature of a separate post), and so didn’t even make it halfway around the rock formations before we had to leave.
Many people were having fun climbing the rocks, leading to great opportunities to add some scale to the pictures:
As we drove home after Greg’s talk we watched a beautiful sunset over I-14, and decided to stop at the park to see what we could find. We got there just as dusk was ending, and the park was sadly closed. But we set up outside and had fun playing with star photography.
Sadly, when I captured the first picture of the night (to test exposure time and composition) and looked at the preview, I thought the lines next to the stars meant that the tripod had vibrated during the shot. Oops. Who knew the stars moved so fast?
Greg then informed me that to freeze the motion of the stars the longest shutter speed you can use is 600 divided by the focal length of the lens. We didn’t know if that was the cropped focal length or the actual focal length of the lens, but I used it as an estimation to get frozen stars: