A GREENHOUSE COLLABORATORY

Brad Bebout and Richard Keller

The Ames Microbial Ecology/Biogeochemistry Research Lab, in combination with the ScienceDesk team, has made significant progress in realizing a greenhouse "collaboratory" which will be shared by members of the NASA Astrobiology Institute's Early Microbial Ecosystems Research Group (EMERG). The greenhouse facility is being used to maintain field-collected microbial mats, as well as perform manipulations of these mats. Microbial mats, extant representatives of Earth’s earliest ecosystems, are highly dynamic communities of microorganisms exhibiting extremely high rates of metabolic processes.   Maintaining the structure and function of these communities outside of the natural environment is therefore a challenge.  Using the greenhouse constructed on the roof of building N239, mats that resemble naturally occurring communities have been maintained over a year after field collection. This year, it was determined that the greenhouse-maintained mats sustain natural rates of biogeochemical processes.  This facility, therefore, is useful to support continued measurements of the rates and conditions under which various trace gases are emitted and/or consumed by microbial mats and stromatolites. The greenhouse mats will be used to investigate the effects of early Earth environmental conditions on the rates of trace gas production and consumption in the microbial mats, a period of Earth’s history no longer available to us for direct measurement. These measurements are also relevant to the search for life on extrasolar planets, where the most promising search strategy involves the detection of possibly biogenic gases using infrared spectrometry. Space-based interferometers, such as the Terrestrial Planet Finder, should be able to resolve the spectra of several biologically important trace gases in the atmospheres of extrasolar planets, possibly within 10-15 years.

The greenhouse represents a unique facility and a unique resource to be shared among EMERG team members. The team’s scientific objectives require multiple collaborators to conduct and analyze measurements of mat parameters on a frequent basis over many weeks. However, pragmatics and funding constraints inhibit the productivity of the distributed team and prevent full utilization of the greenhouse. The construction of a collaboratory – in which human scientists and intelligent agents work together to perform experiments – will alleviate demanding proximity and time requirements that effect productivity. Rather than placing the burden solely on local team members, a collaboratory will enable an entire distributed investigator team to share responsibility for experimentation and data collection.

With this motivation in mind, we have begun construction of a collaboratory designed to enable the geographically distributed group of EMERG scientists to plan greenhouse experiments, operate scientific equipment, take experimental measurements, share results, and collaborate in real time with remote colleagues. Intelligent software agents will assist in the experimentation process, controlling the hardware, recording results, and interacting with the scientists via email. As part of the initial hardware development for the collaboratory, an X,Y,Z positioning table which is capable of automatically positioning sophisticated instruments at any location in the mats has been constructed. The instrument package currently includes microelectrodes, a light sensor, chlorophyll fluorometer, a surface detection device, and a fiber optic spectrometer. The positioning system, and the instrumentation package is viewable over the internet (http://greenhouse.arc.nasa.gov) via a webcam hooked up to a computer located in the greenhouse. Next implementation steps involve controlling the positioning table and equipment remotely over the internet.

Figure 1: Diagrammatic representation of the greenhouse collaboratory with photographs of the hardware already in place. Click image to view larger image.