Coral bleaching severely impacts photosynthesis in corals by causing the loss of the symbiotic algae they rely on for energy.
The Impact of Bleaching on Coral Energy
Coral tissues themselves are not capable of photosynthesis. They depend heavily on a symbiotic relationship with microscopic algae, called zooxanthellae, that live within their tissues. These algae perform photosynthesis, converting sunlight into energy-rich organic compounds (photosynthates) which they share with the coral host.
When corals experience stress, often due to increased water temperatures, they expel these vital symbiotic algae. This expulsion is what causes the coral to turn white or 'bleach', revealing the coral's underlying white skeleton.
As stated by research, the loss of these symbiotic algae in bleached corals results directly in a decrease in photosynthate supply (Lesser, 1997; Warner et al., 1996; Porter et al., 1989). This means the coral loses its primary source of energy from photosynthesis.
- Bleaching Event: Coral experiences stress (e.g., heat).
- Algae Expulsion: The coral expels the symbiotic zooxanthellae.
- Loss of Photosynthesis: With the algae gone, photosynthesis within the coral tissue dramatically decreases or stops entirely.
- Reduced Energy Supply: The coral loses the photosynthates it received from the algae.
- Energy Deficit: This leads to a significant energy deficit for the coral, making it vulnerable and potentially leading to starvation and death if the algae do not return.
In essence, coral bleaching disrupts the symbiotic relationship that enables photosynthesis within the coral animal, leading to a critical reduction in its energy source.
