I see there is a distinct lack of interest in speculative biology. However, I will give it a try.
The Buchanan is a solutional subterranean cavern system exposed for a short period during the formation of the Panthalassic ocean, H2CO3 (carbonic acid) dissolve the surrounding rock. This entire ecosystem and its troglobitic inhabitants rely solely on a single water source, The Caraway River. This extensive river originates deep within the interior as a lake abundant with reducing compounds (such as Fe and S) inhabited by the anaerobic Archaea, the basis of a great food chain. Intense volcanic activity expel large quantities of volatile gasses, and hydroxides, the chemically combined form of H and O, which can divide and fuse again to create HO2 or remain in their isolated form.
Although the source is enduring the river will recede over the course of the year. The river supports a variety of unique biota reminiscent of the Devonian period. Indeed most of the biota migrated prior to the Hangenberg event, an anoxic extinction event that led to the reduction of the O2 and the stimulation of algal pools. But through isolation they managed to survive both the glacial event and the mass extinction due to two primary reasons, the environment of the Caraway can produce its own oxygen via outgassing and it is kept warm by its proximity to the mantle. Through the increased rates of speciation and isolation, thousands of species emerged from basal genera, and given the diversity of its life and its mineral wealth it is a prime candidate for conservation.