Coral reefs are among the most diverse and productive ecosystems on Earth, providing habitat, food, and income for millions of people.
However, coral reefs are also facing unprecedented threats from climate change, which causes rising sea temperatures, ocean acidification, and more frequent and severe bleaching events.
Bleaching occurs when corals expel their symbiotic algae due to stress, losing their color and most of their energy source. If the stress persists, corals can die or become more susceptible to diseases and predators.
To help coral reefs survive and recover from these threats, scientists are exploring various strategies to enhance their resilience and adaptation.
One of these strategies is to accelerate the natural evolution of heat-tolerant corals, using selective breeding, genetic engineering, and microbiome manipulation.
Another strategy is to use automated aquaculture to mass-produce coral larvae and juveniles, and transplant them onto degraded reefs.
These approaches could potentially increase the diversity and abundance of corals that can withstand higher temperatures and other stressors.
Accelerated evolution of heat-tolerant corals
CHANDAN KHANNA/AFP via Getty Images
Corals have different levels of tolerance to heat stress, depending on their species, population, genotype, phenotype, and microbiome.
Some corals can cope with higher temperatures for longer periods than others, while some can acclimatize or adapt to changing conditions over time.
Understanding the genetic and environmental factors that influence coral heat tolerance can help identify the best candidates for selective breeding or genetic modification.
Selective breeding involves crossing corals from different populations or regions that have higher heat tolerance, and testing their offspring for improved performance.
This method can increase the genetic diversity and fitness of corals without introducing foreign genes.
However, it can also pose some risks, such as reducing local adaptation, increasing inbreeding depression, or disrupting ecological interactions.
Genetic engineering involves inserting genes from other organisms that confer heat tolerance or other desirable traits into corals.
This method can create novel combinations of genes that may not occur naturally or take a long time to evolve.
However, it can also pose some ethical, legal, and social issues, such as altering the natural identity of corals, creating unintended consequences, or violating regulations or norms.
Microbiome manipulation involves altering the composition or function of the microorganisms that live in or on corals, such as algae, bacteria, fungi, or viruses.
These microorganisms play important roles in coral health, nutrition, immunity, and stress response. For example, some algae can provide more heat tolerance to their coral hosts than others.
By changing the type or abundance of these microorganisms, it may be possible to enhance coral resilience or recovery.
Automated aquaculture of coral larvae and juveniles
Coral reproduction is a complex and unpredictable process that depends on various biological and environmental factors.
Corals can reproduce sexually by releasing eggs and sperm into the water column during mass spawning events, or asexually by budding or fragmentation.
However, both modes of reproduction face many challenges in the face of climate change, such as reduced fertilization success, larval survival, settlement rate, and growth rate.
To overcome these challenges, scientists are developing automated aquaculture systems that can mass-produce coral larvae and juveniles in controlled conditions, and transplant them onto degraded reefs.
These systems use artificial intelligence, robotics, sensors, and cameras to monitor and manipulate the water quality, temperature, light, flow, and nutrients that affect coral development.
They also use machine learning algorithms to optimize the timing, location, and density of coral seeding.
Automated aquaculture systems can offer several advantages over traditional methods of coral restoration, such as manual fragmentation or transplantation. They can:
Increase the scale and efficiency of coral production and deployment, by reducing human labor and error.
Enhance the genetic diversity and fitness of corals, by using selective breeding or genetic engineering techniques.
Improve the survival and growth of corals, by providing optimal environmental conditions and protection from predators and diseases.
Monitor and evaluate the performance and impact of corals, by using remote sensing and data analysis tools.
