Learning about Lichen

Steve Leavitt is an evolutionary biologist at Brigham Young University and the curator of the lichen collection at BYU’s Life Science Museum. Whether you’re a lichen aficionado or have no idea what a lichen even is, they can be found all around us and play surprising and complex roles. Using lichens, he explores topics of individuality, the nature of science, and why the small, overlooked components of biodiversity matter. When he’s not in the classroom, he loves exploring wild places in the West, seeing new (and familiar) critters and plants, and working with people that are passionate about biodiversity and conservation.

Leavitt Lichen Lab

Published Papers

Science Moab: Lichens require two organisms to exist. Why is that?

Leavitt: One of the partners, evolutionarily, is always trying to take advantage, get the upper hand. And when you think about symbiosis, the iconic image that comes to mind is that they’re getting together and helping each other out, but in reality, it’s more complex than that. The textbook answer is that the fungus is creating a structure that algae can survive, screening UV radiation, and creating a beautiful little growth chamber for the algae. That algae can grow and in return, it’s returning sugars to the fungus, so like a fungus that’s discovered farming. Why does it happen? There’s something evolutionarily advantageous coming from this specific exchange of goods. Whether it’s carbohydrates from the algae, some structural support, or protection from herbivores from the fungus, there’s something happening in this exchange of goods and services that is really good evolutionarily. And in fact,  lichens have evolved multiple times independently.

Science Moab: What draws lichens to grow on rock faces, as opposed to living organisms like trees?

Leavitt: The beauty of a rock face, especially something that’s exposed and hot,may be no competition. If somehow you can figure out a way to survive on that, you have the real estate all to yourself. This may be one of the reasons why lichens evolved: those sugars, the polysaccharides from the algae, can actually be used to help protect the organism from desiccation. So if this fungus could figure out a way to not use those polysaccharides for energy, but rather save them for protection from desiccation, it’s able to colonize these novel and unique habitats. It feels fundamentally different from those beautiful macrolichens in other places. They’re surviving in a different niche. They’re different players, but what they have in common is this reliance on a fungus, an alga, and a whole bunch of microbes to survive. You can have big three dimensional macrolichens that have the same common ancestor as some teeny, tiny crustose lichens that you never see.

Science Moab: Why study lichens?

Leavitt: One of the reasons to study them is simply that they’re weird, they’re interesting, and they’re part of this incredible array of diversity on Earth. We have very little idea of what’s actually going on, and how that diversity came to be. For me, it’s simply that there are questions to try to answer. We can step back across deeper geologic time and recognize that these lichens are fundamentally important for soil formation. They slowly weather or degrade rocks until we end up with productive soils. In other cases, they actually stabilize soil through biological soil crusts, or they can help other vascular plants to germinate or facilitate more effective water infiltration, and retain better moisture in soils. So they actually do have some important ecological roles.

Science Moab: What specifically are you studying right now?

Leavitt: We are into a bit of everything that’s lichens, or even potentially lichen related. We have some projects going on in the La Sal Mountains, and there are some really interesting lichen communities, where we have big lichens just dripping off conifers up in subalpine forests. It looks like something you would see in Alaska or British Columbia, and there’s nowhere else in the state where those occur. So we’re interested in what are those processes that facilitated the formation of these really cool macrolichen communities. We’re interested in using lichens as biomonitors. We can go out and collect a lichen that’s been sitting on a rock for the past few decades, grind it up, and analyze the concentrations for potential pollutants like lead, or iron, or titanium. And then we can use these as proxies to look at air quality. Some of the more interesting stories that these can tell us are things like dust deposition, which actually has some pretty substantial impacts on human health. We’re looking at the profile of the concentrations of different elements. Different dust sources have different signatures, so we can go through and match up those profiles to dust from a specific region.

Science Moab: You look at all these amazing, colorful, different shapes got just infinite numbers of intricate patterns. Can you tell anything from the visual aspect of Aflac in its overall health or anything about it? Or what its host is, I mean, why all these different variations?

Leavitt: A lot of times those colors that we see are produced for sunscreen. If you go out and see a bunch of orange lichens growing on exposed sandstone, it’s likely that those compounds are produced by the fungus as a sunscreen to protect the algae. In other cases, you may see a beautiful green lichen growing on a rock and think it’s the algae that’s making it green. It’s actually usnic acid that the fungus is producing, maybe for anti-herbivory to keep snails from munching on it. The colors are for anti herbivory or sunscreens, the shapes are for ways of dealing with water or heat. What we’re seeing is the interaction between multiple organisms that have evolutionary adaptations that allow them to have preferential success and survive and reproduce.