Putting the Deep Biosphere and Gas Hydrates on the Map

ABSTRACT

Microbial processes in the deep biosphere affect marine sediments, such as the formation of gas hydrate deposits. Gas hydrate deposits offer a large source of natural gas with the potential to augment energy reserves and affect climate and seafloor stability. Despite the significant interdependence between life and geology in the ocean, coverage of the deep biosphere is generally missing in most introductory oceanography textbooks, so there is a need for instructional materials on this important topic. In response to this need, a course module on the deep biosphere with a focus on gas hydrate deposits was created. The module uses Google Earth (Google, Mountain View, CA) to support inquiry-based activities that demonstrate the interaction of the deep biosphere with geology. The module was tried as both a series of in-class exercises and as an out-of-class assignment in an introductory, undergraduate oceanography course. The students took short, preactivity and postactivity quizzes to determine the effectiveness of the module in improving student knowledge about gas hydrates. The module was effective at increasing student knowledge about the basic environmental and biological controls on the formation of gas hydrates on the seafloor. Students showed a consistently low initial comprehension of the content related to gas hydrates, but most (>80%) of the students increased their quiz scores for all module activities. This module on gas hydrate deposits increases the available teaching resources focused on the deep biosphere for geoscience educators.

Key words: :

• deep biosphere
• gas hydrate
• oceanography
• Google Earth

Acknowledgments

This work was supported by a Major Teaching Grant from the Center for Teaching Excellence (CTE) at Miami University (Oxford, OH). We thank Dr. Thomas D. Lorenson from the USGS for providing us with the initial KML layer of gas-hydrate locations used in this module. We would also like to thank Dr. Rob Pockalny from the University of Rhode Island for sharing the microbial cell-abundance data that was used in Activity 2. We are grateful for the constructive feedback we received from the Editor-in-Chief, Associate Editor, and reviewers, which greatly improved this manuscript.