Two lab experiments bring bleached corals back to luminous life, Pg14

Key Highlights:

• Global coral reefs experienced extreme heat stress and the fourth mass bleaching event between 2023-2025, exacerbated by El Niño.
• Indian corals, particularly around Lakshadweep, were also affected by this widespread bleaching.
• Two recent lab studies demonstrated that bleached corals can recover through algae transfer, offering new hope for recovery interventions.
• One study showed direct contact between bleached and healthy corals of the same genetic background could transfer algae and lead to recovery.
• Another study successfully inoculated corals with a lab-made heat-tolerant algal strain, which then spread to other bleached corals.

Coral Bleaching.jpg

Detailed Insights:

• Approximately 80% of the world's coral reefs were impacted by heat stress during the 2023-2025 period.
• Coral bleaching occurs when corals expel symbiotic algae (zooxanthellae) due to environmental stressors like increased ocean temperatures.
• The 2023 El Niño significantly contributed to the severity and extent of the recent global mass coral bleaching event.
• The first study, published in Science, found that algae transfer and recovery were possible only between corals of the same genetic background.
• The second study, published in Environmental Microbiology Reports, used coral species from the Great Barrier Reef.
• This research suggests that reefs might possess greater flexibility in their response to bleaching than previously understood.
• While promising, researchers note that these small-scale experimental findings are still far from large-scale field interventions for reef-wide recovery.

Scientific/Technical Concepts Involved:

• Coral Bleaching: The process where corals expel symbiotic algae due to stress, leading to loss of color and often death.
• El Niño: A climate pattern characterized by the unusual warming of surface waters in the eastern tropical Pacific Ocean.
• Symbiosis: A close and long-term biological interaction between two different biological organisms, such as corals and algae.
• Genet: A group of genetically identical individuals (clones) derived from a single ancestral organism.