Astrobiology and Landscape Ecology: Never the twain shall meet? Lessons learned from FELDSPAR's Iceland volcanic analog sites

The search for life within our solar system is currently limited to robotic missions with limited capacity for instrumentation, analysis and repair. The number and nature of samples taken by rovers is therefore limited, and should ideally be informed by our knowledge of the distribution of life in extreme terrestrial environments which mimic conditions found on Mars, Europa, Enceladus, etc.

FELDSPAR (Field Exploration and Life Detection Science through Planetary Analogue Research) is a NASA PSTAR (Planetary Science Through Analog Research) -funded exploration of the distribution of biomass, biodiversity, and biological activity in seemingly homogenous barren basaltic icy lava fields. We have drawn on the principles of well-established practices in landscape ecology to describe the variability of biological activity and biomass within sediment in a variety of volcanic landscape types mimicking those found on Mars - areas that have been resurfaced due to eruption, aeolian deposition, and/or fluvial action. In addition, we attempt to link mineralogical data that might be collected by a rover mission to areas with either higher biosignature probability (higher sampling priority) or higher variability (requiring greater sample number or resolution). Adenosine triphosphate (ATP) quantification is used as a proxy for bioavailable energy and activity, and biomass and biodiversity have been measured through cell counts, DNA quantitation, and community sequencing.

Recent deglaciation/fluvial action and recent resurfacing from lava flows at our field sites have resulted in greater spatial variability of biological activity at greater scales, but little to no spatial variability in actual biomass. Both activity and biomass experience 'hot moments' or 'hot spots'. If these are included as valid analogs for extraterrestrial biosignatures, the number and spatial scale of samples necessary to characterize an area depends mainly on whether such a 'hot spot' receives a hit - a difficult prediction in a homogenous environment. On the other hand, should such areas be excluded as irrelevant to astrobiology? Here we present a variety of statistical techniques we have used to attempt to answer this question - do the rules of terrestrial landscape ecology apply on extreme environments?