Corals demonstrate an ability to partially adapt to the ocean environment through a combination of natural selection and changes in their symbiotic relationships.
Corals adapt to the ocean, particularly in response to stressors like heat, by allowing more resistant individuals to survive and repopulate areas and by associating with heat-tolerant algae.
Key Adaptation Mechanisms
Based on observations, the partial adaptation seen in corals can be attributed to multiple interacting factors. Two significant mechanisms identified are:
1. Survival of the Fittest Corals
- When corals that are highly sensitive to environmental changes, such as rising temperatures, succumb and die, they leave behind space on the reef.
- More robust and inherently resistant corals are then able to survive in these conditions.
- These resistant corals can reproduce and spread, effectively repopulating the vacated areas with individuals better equipped to handle the challenging environment. This process reflects a form of natural selection at the coral population level.
2. Symbiont Switching
- Corals live in a symbiotic relationship with tiny algae called zooxanthellae, which reside within their tissues. These algae are crucial for the coral's survival, providing food through photosynthesis.
- Under stress, especially heat stress, corals may expel their usual symbiotic algae, a process known as bleaching.
- Crucially, corals can sometimes replace the ejected algae with different types of algae.
- Some types of zooxanthellae are better able to withstand higher temperatures than others. By hosting these more heat-tolerant algae, the coral itself becomes more resilient to warming waters.
These mechanisms highlight how corals can, to some extent, adjust and persist in changing ocean conditions, though their ability to adapt may be outpaced by the speed of environmental change.
Summary of Adaptation Factors
| Adaptation Type | Mechanism | Outcome |
|---|---|---|
| Population Adaptation | Sensitive corals die; resistant corals survive and reproduce. | Reef areas repopulated by more resilient coral genotypes. |
| Physiological/Symbiotic | Ejected heat-sensitive algae are replaced with heat-tolerant algae types. | Individual coral polyps become more heat-resistant. |
Information derived from observations reported on 12-Nov-2013 attributing partial adaptation to these factors.
