An aperture is an opening—of an eye, a camera, a telescope—a boundary between inside and out. It’s the device that determines how much light gets into an optical system and illuminates an otherwise dark interior. The aperture is also a frame. It’s not only about how much light the aperture lets in, but how much light it keeps out. In this act of mediation, the aperture itself typically disappears from view.

We choose to focus on the aperture itself as much as the image it produces by putting stills from a video artwork in dialogue with an essay exploring Texas’s caves. Between the two, the aperture is a device that helps us consider the politics of framing. The mouths of the caves are apertures that frame relations among scientists, landowners, and the public. Apertures thus mediate not only light and dark, but also inside and out, private and public, knowledge and risk. Apertures are contested sites, both epistemic and material.

This essay includes stills from Postcard, a video piece depicting a narrow view of the sunset. As the sunlight fades into darkness, it becomes clear that the frame around the view is not just a static border. Rather, it is a physical surface onto which another video has been projected—a video that slowly comes into view as the sun sets. Postcard reveals our propensity to overlook what the aperture obscures.

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You don’t know that there is a vast cave underneath your feet until the bats emerge at sunset. They spill out of a small hole—a nearly unnoticeable tear in the landscape. As the light fades, one, five, ten bats swirl into a cloudless sky. In seconds, more bats pour up out of the cave, fast and hungry, at such a rate that they seem liquid, like a single body rather than a swarm of individuals.

As these bats emerge en masse, you start to get a sense of the cave’s interior—ever expanding, its contents continuously spilling out. The experience evokes a combination of wonder at the spectacle and anxiety at the dawning awareness that the ground is not solid after all. It is hollow: full of bats, but also of potential knowledge.

When you think of the underground in Texas, it is hard not to conjure images of oil fields tapped by countless derricks. But caves are just as prevalent here. As the population of Texas balloons and its subterranean water resources dwindle, its caves have become valuable resources for scientists who want to better understand this landscape in order to conserve it.

The specific caves of interest here are karst caves, which are formed through the dissolution of limestone. Karsts often act as aquifers, sustaining life on otherwise inhospitable semi-arid land. By definition, karsts are caves that have an opening—an aperture—to the surface, allowing things to move in and out of their interiors.

These caves are like laboratories: they hold certain conditions constant, like internal temperature and humidity. Karst caves remain relatively insulated, their microclimates controlled, their interiors uncannily out of time. They therefore allow scientists to identify and observe the statistical patterns that emerge from non-fixed variables, like the movement of water.

But they are not completely isolated. Even slight internal changes index external disturbances. This makes karst caves useful in studying wider climatic changes over time. Similarly to archeological digs, paleoecologists can find within them relics of historical ecosystems. Data from these spaces is used to visualize the otherwise invisible phenomena of the karst cave’s interior, effectively turning the karst inside out.

Karsts are messy apertures, with animals, people, air, and water constantly spilling in and out. Translating them into models that help scientists study climate change requires obscuring a lot of messy circumstances—the site-specific processes by which data is collected, as well as the on-the-ground debates over land use that climate science occasions.

Environmental scientists hope that these models will shape global climate science on the one hand and local environmental management on the other. There is very little environmental regulation in Texas, and over ninety-five percent of the land in the state is private property. Many landowners fear that research wielded by the state will undermine property rights.

Across Texas, the karst is thus contested between private landowners and science. Unlike almost anywhere else in the world, in Texas, the subterranean is legally under the aboveground landowners’ domain. Texas law holds that landowners’ property rights extend “from heaven to hell,” that is, volumetrically above and below the surface of the land. This is why the entire oil industry in Texas is dependent on private land ownership: it is the landowner who controls the mineral rights and the potential value there, and no one else. This means that, despite being easy to walk into, karsts are notoriously difficult to access in the first place.

Scientists in Texas share secret maps of the state’s caves with one another because finding out where their openings are is nearly impossible. The relationships they build with landowners are always tenuous. One misstep can sour that relationship for everyone, which makes it impossible for outsiders to access that land in perpetuity, and ends the production of scientific knowledge there.

It is only after finding the karst caves, signing liability waivers, and assuaging landowner anxieties about data privacy, that scientists can finally enter these spaces. Then, wearing protective gear, kneepads, and headlamps, scientists carry all their technical equipment underground to record air quality, swab living organisms, and track changes in the stalagmites and stalactites.

Some landowners, prompted by indications from scientists that there is something special about their subterranean estates, charge researchers and the public fees to enter them, or to watch bats exit them. Other landowners respond differently. Sometimes they deny scientists access, citing fears of federal intervention on their property if, for example, endangered species were found there.

It’s also not unusual to see landowners fill their karst caves with rocks, dirt, or even household garbage and hazardous materials. They call them “Texas trash holes.” The practice ensures that nothing can move in or out of them. It risks polluting soil and water systems and animal habitats with dangerous toxic material. It also makes these spaces no longer, by definition, karst caves.

The movement of scientists, like bats, in and out of these caves creates an unstable terrain of desire and fear around the openings to Texas’s underground. The caves become an ethnographic aperture for watching scientists and landowners negotiate the terms of knowledge production. Sometimes, the very act of pursuing scientific research makes these places less knowable. In Texas, decisions are made not necessarily in a legislative session, or on the national stage, but on private land.

Like the microclimate of the karst, even as the external climate changes, some things hold steady across environmental management projects in Texas, like the settler colonial property regime and a desire to escape oversight. Looking at these karsts through the frame of property relations can help us see more widespread patterns of land use.

Our apertures are changing. Unstable scientific funding, strained property rights, and runaway climate change all mediate the landscape’s visibility and accessibility. Often, the attempt to access these spaces exacerbates their opacity. What we see instead is the role of property in the practice of science.

Environmental knowledge in Texas, and across the settler southwest, is a game of apertures—of finding openings and framings across law and land. Karst caves illustrate how defining the land’s interior is a matter of apertures all the way down, of framing models, relationships, and public perception by what goes in and what stays out. ⦿