Page 10 - ME Newsletter Fall

SAVING CORAL REEFS SAVING CORAL REEFS
Researchers in Professor John Bischof’s Bioheat and Mass Transfer Lab are working with coral conservation partners at the Smithsonian Conservation Biology Institute, Taronga Zoo in Australia, Florida Aquarium, Caribbean Research and Management of Biodiversity (CARMABI) on the island of Curaçao, and elsewhere. The team contributes expertise in the modeling and optimization of cryopreservation methods and develops novel cryopreservation technologies to work toward banking important genetic resources that have never been preservable with previous technology.
This partnership stems from a long-time collaboration between Bischof and Dr. Mary Hagedorn, a senior research scientist at the Smithsonian Institution. Nikolas Zuchowicz was a technician under Dr. Hagedorn, and is now a PhD candidate in Bischof’s group. In his PhD work, Zuchowicz acts as a bridge between UMN’s conservation partners and the engineering community, testing new cryopreservation technologies in the field to support methods to secure the genetic diversity of threatened species, including locally and globally endangered corals such as the pillar coral, Dendrogyra cylindrus.
Coral cryopreservation has been developed over the past 20 years or so, first by Dr. Hagedorn, and more recently by a broader consortium of research groups, most of which are sited near tropical reef systems and so have
ready access to fresh coral spawn. With the technical knowledge of UMN
ME researchers, combined with the practical cryopreservation and animal husbandry know-how of the team’s partners, they’ve been able to build rapidly on the successes of the past two decades, refining protocols and expanding cryopreservation capabilities. This network’s expertise can enable coral aquaculture and population genetic management to sustain healthy reefs into the future.
Larvae of the mushroom coral are shown in the glassy state under liquid nitrogen at −196 °C. The strands of the metal cryomesh used to preserve them are visible between the larvae, which are indicated with white asterisks.
Photo credit: Nikolas Zuchowicz
An unexpected and important result in cryopreservation is that warming is often a more dangerous process than cooling, so warming must occur orders of magnitude more rapidly than
cooling to avoid the formation of crystalline ice.
To overcome this barrier, the group has worked
for several years on extremely rapid cooling and warming technologies such as infrared laser rewarming and, more recently, an inexpensive and scalable technology they call conduction-dominated
cryomesh, a project led by Dr. Zongqi Guo, until recently a postdoc in Bischof’s group. In both cases, vitrified (glassy solid) samples are returned from cryogenic temperature to room temperature in a
fraction of a second, outrunning the nucleation and growth of ice crystals and allowing the survival of the cells within. Another recent success following this process is a proof-of-concept of laser nanowarming of coral adult tissues, opening the way for future work in preserving small fragments of coral that could be revived in the future to regrow whole coral colonies.
10 ME News Fall 2024