Nutrients, Maintenance, Energy and Growth: predicting habitability, biomass and biosignatures from limited datasets

Abstract:

Astrobiology has the challenge of studying life on Earth in environments which are poorly characterised or extreme, usually both, and assessing the habitability of extraterrestrial environments with wide-ranging parameter spaces. We need an effective way to do this with the limited datasets we have, or at least a method to pinpoint which parameters we need to understand better to improve these assessments. But how do we do this, while remaining as agnostic to life as-we-know-it as possible?

We have developed a general astrobiological model for assessing the energetic and nutrient availability of poorly characterised environments to predict their potential biological productivity. NutMEG [Nutrients, Maintenance, Energy and Growth] can be used to estimate to first order how much biomass an environment could provide to life, and how such life might affect the local chemistry. It requires only an overall catabolic reaction and some knowledge of the local environment to begin making estimations, with many more customisable parameters such as specific microbial behaviours and adaptation – allowing habitability assessments to improve as we learn more about our targets and their potential inhabitants.

With minimal assumptions NutMEG can reliably replicate microbial growth behaviour. Its computationally lightweight design also allows us to consider wide parameter spaces and identify the most critical inhibitors to habitability.

NutMEG can help us assess the theoretical habitability of extraterrestrial environments and predict potential biomass and biosignature production. We will introduce the ideas behind NutMEG’s philosophy and explore its applications from the habitability of poorly-characterised environments (e.g. icy moons) to estimating biosignature production on hypothetical exoplanets.