## Problem 315 — rank:202

**Title:** Limits of the deep biosphere

**Added binding assumptions (LaTeX):**

```latex
Fix sign conventions for usable free energy, conversion efficiency and the accounting of initially stored reserves. The long-run power balance can be necessary under a closed budget while failing to characterize finite-horizon survival or growth with reserves. Net growth, survival of dormant cells and assay nondetection are separate quantities. Boundary estimation requires positive margins or reports a band where the sign of growth remains unresolved.
```

**Direct edits:** 0. **Fresh external checks:** None; supplied sources retained as provenance.