#ellyllo

In modern times, these fantastically lethal ecosystems have given a practical solution to a serious challenge faced by those districts which have been buried beneath layers of architecture: a way to contain and neutralize gasses spewed by chimneys that have been blocked by newly unfolded districts. Instead of cutting paths upward through the young, malleable new sarchitecture, as such openings are not guaranteed to last, given how newly unfolded Sarchi continue to adjust their walls and layout for decades after unfolding, the vents are redirected to special, sealed off areas, usually selected from unpopulated industrial areas, although ghettos, apartment mazes, and other low-income, ‘undesirable’ neighborhoods are also frequent choices. Areas with high populations of Azo are especially common Liver Zone candidates, as their apparently disorganized nature and refusal to participate in Harusper society entails them no legal rights or protections when it comes to persuading district counsels to select some other unfortunate area. Oftentimes the only forewarning inhabitants are given is the beginning of construction to seal off every road, pipe, crack and crevice around the newly selected zone. From there they simply have no choice but to find a new home as water, heat, traffic, and eventually air are cut off one by one up until the vents are connected and the gas floods in. Most, of course, do pleave, but some, especially the old, infirm, and those without families, are either left abandoned or stubbornly remain to meet their deaths, their bodies becoming fodder for the flora and fauna which will soon be seeded. 

After the gas has built up to suitable concentrations, organisms carefully harvested from pre-established Liver Zones are introduced. These ecosystems are delicate, and like foul, lightless gardens, must be cared for and maintained to retain optimal levels of functioning. Additionally, many species of economic importance are endemic to these induced ecosystems, including several species of tryllichens which can be processed into a high end plastic that's now found in many common products throughout the city, and multiple plants and animals which produce chemicals of pharmaceutical importance and interest.