The KIGAM team's peer-reviewed study in Communications Earth & Environment identifies stromatolites within the Hapcheon crater, formed in a post-impact hydrothermal lake. Geochemical signatures of extraterrestrial material and hot-water alteration were measured in structures 10-20 cm across from the northwestern crater rim; inner layers showed stronger hydrothermal imprints, consistent with early high-temperature conditions cooling over time. This single-site discovery (n=several structures) supports localized 'oxygen oases' but cannot quantify global flux without broader sampling. Linking this to the 2021 Gondwana Research confirmation of the crater and to papers on impact-generated hydrothermal systems (e.g., Osinski et al., 2020 in Astrobiology), the pattern emerges that large impacts ~2.4 Ga created mineral-rich, long-lived lakes favoring cyanobacterial mats precisely when atmospheric oxygen rose. Earlier models of the Great Oxidation Event treated it as a diffuse planetary threshold; the Korean data instead point to discrete impact 'nurseries' that bootstrapped oxygenic photosynthesis before planetary-scale mixing. Limitations include reliance on one Korean site and absence of direct radiometric dates tying stromatolite growth to the GOE interval. Similar crater lakes on early Mars remain high-priority targets.