Doctor of Philosophy / Today there is scientific consensus that human activity has significantly altered our planet, a condition often referred to as the Anthropocene. The effects of these changes can be hard to understand or predict, however, due to the size and complexity of Earth's biological, chemical, and geological systems. This dissertation argues that one way to better grasp the complex and uncertain effects of the Anthropocene is through a careful comparison with the outcomes of a smaller-scale human-built environment that was meant to mimic Earth's ecosystems: Biosphere 2 [B2]. B2 was an ambitious "Human Experiment" designed to create a self-sufficient 'mini-Earth' inside a glass dome in Arizona. From 1991 to 1993, eight humans and 3,800 other species inhabited this recreation of Earth's biosphere, where the Biospherians grew all their food, recycled their water, and oversaw the production of their atmosphere, as well as conducting scientific research on this novel ecosystem. While the mission ran into unexpected difficulties that led many to label it a failure, this dissertation argues that the project actually succeeded in many ways, and that even its failures can be instructive for understanding today's environmental challenges. Two aspects of the B2 experiment can help us understand analogous aspects of the Anthropocene. First, B2's attempt to create and maintain an ecosystem that could provide everything needed to support life within a tightly enclosed structure reveals how enclosed environments have their own unique characteristics that can lead to unexpected and even disastrous results. I call these characteristics "Logics of Enclosure," and I argue that these same logics apply to the Anthropocene, as we begin to recognize that we, too, live in a world with limited resources and increasingly tight connections between its ecosystems. The dissertation describes various types of Logics of Enclosure and how they can be used to explain the outcomes of B2 and potentially alert us to similar outcomes within our increasingly 'enclosed' Anthropocene. The second unusual feature of B2 is that the Biospherians combined a number of roles that are normally separate within the fields of science, engineering and architecture. The same group of people helped develop the scientific field of Biospherics, designed B2's structural, technological, and biological contents, and then inhabited the world they had created. I refer to this as the knowledge–design–inhabitation trajectory, and I argue that in the Anthropocene we, too, are living in a world that is increasingly the result of our own design, based on our own imperfect scientific knowledge. These two forms of analysis work together: Logics of Enclosure explain how the hybrid built/natural environment has agency to affect human life, while the knowledge–design–inhabitation trajectory explains how we, the human inhabitants of Earth, have agency to better align our actions and technologies with our planet's life-supporting ecosystems. Ultimately, using these lenses to understand B2's outcomes may inform more successful longduration approaches for living within the Anthropocene.

A study was undertaken to explore relationships between wetland characteristics which make them efficient water purifiers versus their ability to serve as wildlife habitat. The effects of designing constructed wetlands for improved habitat on water treatment efficiencies were quantified. Results indicate that some sacrifice in treatment efficiency is required and that the degree of efficiency reduction is dependant upon pollutant loading rates. However, sacrifice in efficiency is much smaller than increase in habitat quality, and can be offset by increasing wetland area. A practical, theoretical application was then attempted.