IMOG 2021 | 2021
POST IMPACT RECOVERY OF THE DEEP GRANITIC BIOSPHERE OF THE CHICXULUB IMPACT CRATER
Abstract
Summary The Chicxulub crater (Yucatan Peninsula, Mexico) is the third-largest, but the only well preserved large meteorite impact structure on earth. The 180 km-wide Chicxulub crater was created ∼66.5 Ma ago upon impact by the 14 km diameter asteroid that caused the Cretaceous–Paleogene (K–Pg) mass extinction involving all non-avian dinosaurs as well as 75% of all terrestrial and aquatic species. The previous studies are limited to fossilizing species, but recent studies have reported the post-impact recovery and return of surface-dwelling microbial life to the Chicxulub impact crater site. However, to what extent the deep biosphere was able to recover from the impact required further investigation. In 2016, an 829.03-meters-long core between 505.7 to 1334.73 meters below the seafloor (mbsf) within the craters’ peak ring was recovered as part of the International Ocean Discovery Program (IODP) Expedition 364. We studied the diversity and distribution of microbial community present in the granitic basement and associated mineral veins (774.41–1334.73 mbsf) of the recovered core through environmental 16S rRNA sequencing. The preliminary results show that deep biosphere comprises a highly diverse community of putative thermophilic heterotrophic, sulfate-reducing, and Mn-oxidizing bacteria as well as putative hydrogenotrophic cyanobacteria.