Texas Tech University will be one of three U.S. host sites analyzing what life grows on surfaces exposed to external climates and what life grows on top of them, seeking outcomes relevant to the U.S. Department of Defense.
One of the more readily visible examples of biological succession, or the ordered stages of development from barren land to a rich ecosystem, can be found on the Island of Hawai‘i, the largest of the chain of islands comprising the country’s 50th state.
The Hakalau Forest National Wildlife Refuge on the island’s northeastern side lies east of the Mauna Kea volcano that has been dormant for approximately the last 4,500 years. Facing the sodden trade winds from the northeast, the rain forest has developed substantially since lava flows last destroyed everything in its path, thanks to both time and wet conditions.
Amanda M.V. Brown, a Texas Tech University associate professor in the Department of Biological Sciences, points to the process of tiny microbes falling out of the air and landing on grimy surfaces, analogous to windborne ferns taking root on a barren lava flow. On surfaces all over Earth, pioneer microbes land and, just by living, may create a warm welcome for less rugged microbes. Over time, stage by stage, surface grime may develop into a miniature but mature ecosystem, echoing succession in the Hakalau Forest's growth.
“There are a lot of hidden processes that nobody understands very well,” Brown said.
She’ll soon investigate those hidden processes of succession herself as part of a team of researchers at Texas Tech, Iowa State University, Purdue University, and the universities of Hawai’i and Iowa.
The Army Research Office at the Department of Defense has funded this endeavor with $9 million over five years, through the prestigious Multidisciplinary University Research Initiative (MURI) that accelerates research via collaboration across universities. Brown’s TTU team will receive a total of $1.5 million for this research.
Amy Charles, the project's research support specialist at the University of Iowa, said the project continues beyond previous research examining how airborne chemicals land on surfaces and build up into environmental films, ultrathin strips of "grime" that separate all surfaces from the air.
“There’s also life forms that stick on there, such as mold -- mold spores -- fungus, bacteria, algae; all kinds of stuff lands on there, and some of it lives, and then some of it thrives,” Charles said. “If you look around you, or if you go outside, there’s this layer of stuff covering everything.
"What happens in there? Do we get these little 'forests' in there? How do they work?”
That’s where biologists like Brown come in, to attack a subject so microscopic yet so captivating.
“We want to understand the processes occurring when we clean a surface, sterilizing it, like lava clearing out all life in its path,” Brown said. “What happens after, and does the type of surface affect the succession that follows or the final structure of the film?"
The field site of the National Wind Institute at the Reese Technology Center will be one of the project’s host sites for conducting long-term sampling, placing aluminum alloy, silicon and polymer plastic-coated surfaces out in the arid West Texas climate before eventually swapping them with those placed in Hawai‘i. Samples will also be placed in the temperate Iowa environment.
Brown said the group hypothesizes that the surfaces in all locations will experience similar processes of succession despite the varying climates and potentially large variations in microbial mixes and their growth rates at the beginning of the experiment.
If successful, this research will offer the first model of how these ubiquitous films form, mature, climax and recover during growth and potential disruption over months and years.
Brown added that the U.S. military could potentially benefit from learning what grows on military surfaces and makes them difficult to clean, though this stage of research is far from applications. The research could also yield improved approaches to designing coatings and materials that can completely resist film formation, be easily and wholly cleaned, or promote fast and complete coverage by a beneficial film.
Brown is new to researching environmental films. Her lab at Texas Tech and previous research focuses on microbes that live inside organisms and affect biochemical processes in animals and plants. She also studies genomics, determining the complete sequences of DNA molecules in organisms, or their genomes, to identify and interpret their functional elements.
Brown was intrigued by the MURI project’s inclusion of different habitats, especially Hawai‘i, a tropical ecosystem like one of her other research sites in Brazil. In both projects, one of the goals is to understand cooperation and co-dependence in microbially rich habitats.
“We know the concept of natural selection is that organisms that have a bit more resources will multiply more quickly and will spread, and sharing or giving away your resources is not exactly consistent with that,” she said. “Yet we see cooperation again and again, in every ecosystem.”
Codependency between organisms, especially microbes, amidst competition is what
Brown characterizes as a paradox and a phenomenon that’s fascinated her throughout her career.
With this project, she’ll delve into growth and succession in hostile environments, which Brown reasons would necessitate more cooperation for survival.
The inclusion of biologists and chemists as teammates in this endeavor continues the theme of partnership. The project will progress by examining films for both biological and chemical information, and – researchers hope – putting these puzzle pieces together to make one picture of how succession works on such a tiny scale.
“The project requires us to understand each other enough to make sense of what we’re trying to do and then make sense of the outcome,” Brown said. “That maybe sounds easy, but it’s actually going to be one of the hardest things about the project.”
The project also represents the first biologically and chemically integrative study of the interfaces between gas and solid, and its methodology could serve as a foundation for an emerging field of producing more complete interpretations of ecological succession.
“Ecological theory and frameworks that have been central to microbial ecology for decades will be unified with physical morphology and chemistry for the first time in the environmental film system,” the proposal’s abstract reads.
Brown is thrilled to have the opportunity to join this new project.
“I was suddenly excited by the idea of looking at cooperation in this project, and anything where I can look at that concept in a new way is intriguing to me,” Brown said.
Her interest in this aspect of nature was what brought her to Texas Tech in 2016, the culmination of a gradual journey southward from Canada.
From a young age, Brown recognized the importance of microbes that live within larger organisms such as humans and are crucial to survival. She earned undergraduate and doctorate degrees in ecology and molecular evolution, respectively, from the University of British Columbia.
Brown’s postdoctorate experiences took her to Montana and Oregon before coming to Texas Tech as a faculty member.
The Department of Biological Sciences’ support of diverse research interests including genetics and genomics, cell, animal and plant biology, as well as microbiology made for a great fit, as Brown’s pursuit of answering her research question regarding cooperation couldn’t be limited to one category.
“Chemists are looking at the particle level, which really represents the building blocks of living things, but making sense of those particles and how they affect communities of organisms and vice versa is going to be interesting,” Brown said. “I'm sure there'll be some patterns that are quite new discoveries.”