Biology subjects

Bouwmeester, J.

Publications and source records attributed to Bouwmeester, J..

4 recordsLinked to original sources

bioRxiv2023

The first proof of concept demonstration of nanowarming in coral tissue

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.

ecology↗

bioRxiv2023

Metrics of Coral Microfragment Viability

Coral reefs are being degraded at unprecedented rates and decisive intervention actions are urgently needed to help them. One such intervention in aid of reefs is coral cryopreservation. Although the cryopreservation of coral sperm and larvae has been achieved, preservation of coral fragments including both its tissue and skeleton, has not. The goal of this paper was to understand and assess the physiological stressors that might underlie coral fragment cryopreservation and the long-term consequences of these physiological exposures to continued growth. Therefore, we assessed small fragments ([~]0.5 x0.5 mm2) from the Hawaiian coral, Porites compressa, examining: 1) the sensitivity of the fragments and their algal symbionts to chilling temperatures; 2) the sensitivity of the coral to complex cryoprotectants; 3) methods to safely remove the algal symbionts from the coral fragment for cryopreservation, given the two symbiotic partners may require different cryopreservation protocols; 4) continued growth over time of coral fragments once returned to running seawater after treatment exposures; and, 5) assessment of health and viability of microfragments after treatments examining the distribution of green fluorescent protein and fluorescent symbionts. Technological advances in cryo-technology promise to support successful coral fragment cryopreservation soon, and its success could help secure much of the genetic and biodiversity of reefs in the next decade.

cell biology↗

bioRxiv2022

Tank Fouling Community Enhances Coral Microfragment Growth

Anthropogenic stressors threaten reefs worldwide and natural in situ coral reproduction may be inadequate to meet this challenge. Land-based culture can provide increased coral growth, especially with microfragments. We tested whether culture methods using different algal fouling communities could improve the growth and health metrics of microfragments of the Hawaiian coral, Porites compressa. Culture method fouling communities were: 1) similar to a reef environment (Mini Reef); 2) clean tanks managed to promote crustose coralline algae (Clean Start); and, 3) tanks curated beforehand with poorly-competing algae (Green Film) assessed in winter and summer months. The Green Film method during the winter produced the fastest microfragment mean growth at 28 days until the first row of new polyps developed and the highest tank metric scores. Time efficient, standardized methods for land-based culture designed to maximize growth and production of coral fragments will contribute considerably to the success of large scale restoration efforts.

zoology↗

bioRxiv2022

Securing algal endosymbiont communities for reef-building corals

Photosynthetic dinoflagellates that live in symbiosis with corals (family Symbiodiniaceae) are fundamental for the survival of coral reef ecosystems. During coral bleaching events, it is assumed that these symbionts remain available in the water column, in sediments, or are seeded from unbleached coral colonies. Yet, this hypothesis has not been verified and it remains unclear whether some diversity of Symbiodiniaceae may be lost in the process. Culture methods have been developed for some Symbiodiniaceae, but for the vast majority of these photosynthetic symbionts, known culture methods are not successful at maintaining them for extensive periods. For these unculturable symbionts, cryopreservation, which places cells and tissues in suspended animation for days to decades, offers the best hope for saving the biodiversity of these crucial coral partners. Some cryopreservation processes use slow freezing, but if the cells are sensitive to low temperatures, as is the case for Symbiodiniaceae, then rapid freezing, called vitrification, is needed. We here, tested two published vitrification protocols that had been designed for algal symbionts extracted from Hawaiian corals, but we were unable to recover living symbionts after vitrification and warming. Therefore, we report a successful optimisation of the former vitrification protocols, which we tested on algal symbionts freshly extracted from three Hawaiian coral species, the development of ultra-rapid laser-warming cryopreservation techniques for symbionts, and banking procedures for algal symbionts. We also present some successful uptake of cryopreserved algal symbionts by coral larvae, although at a low rate. It is unclear why the former vitrification protocols failed but we propose that it may have been related to thermal stress and bleaching events that occurred on several occasions throughout the Hawaiian Islands. Maintenance of biodiversity is essential for sustaining functional, productive ecosystems with the adaptability to effectively recover from disturbances. By successfully cryopreserving and banking coral symbionts, we provide a critically needed component for securing Symbiodiniaceae biodiversity into the future.

zoology↗