GREENER principles for environmentally sustainable computational science.

The carbon footprint of scientific computing is substantial, but environmentally sustainable computational science (ESCS) is a nascent field with many opportunities to thrive. To realize the immense green opportunities and continued, yet sustainable, growth of computer science, we must take a coordinated approach to our current challenges, including greater awareness and transparency, improved estimation and wider reporting of environmental impacts. Here, we present a snapshot of where ESCS stands today and introduce the GREENER set of principles, as well as guidance for best practices moving forward.

Sulfur disproportionating microbial communities in a dynamic, microoxic-sulfidic karst system.

Biogeochemical sulfur cycling in sulfidic karst systems is largely driven by abiotic and biological sulfide oxidation, but the fate of elemental sulfur (S ) that accumulates in these systems is not well understood. The Frasassi Cave system (Italy) is intersected by a sulfidic aquifer that mixes with small quantities of oxygen-rich meteoric water, creating Proterozoic-like conditions and supporting a prolific ecosystem driven by sulfur-based chemolithoautotrophy. To better understand the cycling of S in this environment, we examined the geochemistry and microbiology of sediments underlying widespread sulfide-oxidizing mats dominated by Beggiatoa.

Sulfur cycling at natural hydrocarbon and sulfur seeps in Santa Paula Creek, CA.

Biogeochemical cycling of sulfur is relatively understudied in terrestrial environments compared to marine environments. However, the comparative ease of access, observation, and sampling of terrestrial settings can expand our understanding of organisms and processes important in the modern sulfur cycle. Furthermore, these sites may allow for the discovery of useful process analogs for ancient sulfur-metabolizing microbial communities at times in Earth's past when atmospheric O concentrations were lower and sulfide was more prevalent in Earth surface environments.