MO: Kartchner Caverns: Habitat Scale Community Structure and Function in Carbonate Caves

University Of Arizona, Tucson AZ

Investigators

Abstract

The subject of this NSF Microbial Observatory (MO) is Kartchner Caverns in Benson, Arizona, one of the top ten carbonate caves in the world in terms of mineral and cave formation diversity. Until they are discovered, underground caves are ancient, fragile, nutrient-poor, and isolated systems with little or no connection to surrounding environments. Upon discovery and without proper management, damage to these systems can be irreversible. Scientifically, caves are of interest because it is likely they harbor undiscovered and novel microorganisms and because these insulated systems are devoid of light, and may harbor unique microbial activities as well. For the general public, caves harbor fascinating and beautiful formations that generate interest in science and the preservation of unique and fragile ecosystems. The objectives of the Kartchner Caverns MO are: 1) to identify novel organisms associated with different parts of the cave including formations, walls, and mud using both culture methods and advanced molecular tools to analyze DNA signatures, 2) to construct a complete DNA (metagenomic) library and database for correlating specific DNA sequences with microbial activities in the cave environment (e.g., participation in creating the formations), 3) to examine how microbial communities change across defined carbon gradients in the cave to help define how tourism, which brings in substantial amounts of extra organic carbon (e.g., lint, hair, skin cells), has impacted the cave, and 4) to analyze soap-like molecules (biosurfactants) produced by formation-associated microorganisms and incorporate their contributions into modeling the growth process of the formations. Fundamental understanding of the biology of cave systems, in general, is lacking. This is a major impediment to sustainable public development of these unique and delicate ecosystems. Thus, the scope of this research is both timely and comprehensive in regard to the study of cave microbial diversity. The broader impacts of this project include the establishment of both microbial and DNA (metagenomic) libraries that will comprise the most detailed, surface-specific cave collections to date. These libraries will provide insights into the selective forces that drive the microbial biology of subterranean nutrient-deprived existence. The libraries will also be made widely available for screening and data mining for biotechnological and biomedical applications. The studies along various gradients (inorganic and organic carbon) will provide insight into how environmental factors impact the associated microbial communities and the attendant health and stability of the cave system. Finally, the integration of biosurfactant production into models of formation development represents one of the first efforts to understand microbial contributions to formation growth. In summary, this MO will establish a world-wide resource for the advancement of contemporary research on cave microbiology and provide valuable tools for the global preservation of caves and cave formations. The broader impacts of this MO go far beyond research. Educational impacts include training of post-doctoral, graduate, and undergraduate students to prepare a new generation of scientists in modern microbiological methods to address contemporary challenges in cave conservation and microbial diversity in other fragile, unique environments. Outreach efforts will impact several hundred thousand people per year and include: (i) an annual Kartchner Caverns lecture series for Park personnel and docents to provide a microbiology background and an update on project progress and findings which will then be passed on to Park visitors (~200,000/year), (ii) a high-quality interactive display for the Kartchner Educational Center to provide Park visitors a unique opportunity to learn about cave microbiology, the MO, and recent findings, (iii) production of a high-definition DVD by the University of Arizona nationally acclaimed PBS affiliate, KUAT, that highlights the MO project and its role in understanding microbial diversity in Kartchner Caverns, (iv) development of a module for Arizona State Parks educational curriculum that is targeted at grades 7-12, and (v) a Kartchner Caverns MO website with reciprocal links to the Kartchner Caverns website and the Friends of Kartchner Cavern website (together, these websites receive over 50K hits monthly).