The first proof of concept demonstration of nanowarming in coral tissue

Abstract

Climate change is causing ocean acidification and warming, resulting in mass bleaching and death of corals globally. Cryopreservation and biobanking to secure the genetics of threatened populations is currently limited to coral sperm and larvae, which are only available during brief annual spawning events and are impacted by ocean warming, so there is an urgent need for methods to enable biobanking activities year-round. Here, we used vitrification and nanowarming to successfully recover adult coral tissues in a novel sample type, the single-polyp microfragment (SPMF). Fluorescence and confocal microscopy showed clearly defined tissues and green fluorescent protein fluorescence around the polyp mouth post-warming in 43.3% of SPMFs at 24 hours post-warming, and 30.0% at one month. These advances provide a basis for continued research and development of a field-ready protocol for cryopreservation of adult coral tissues, to permit biobanking of threatened coral species throughout the year and support reef restoration efforts.