Corals

Definition

Corals are marine invertebrates belonging to the class Anthozoa within the phylum Cnidaria, characterized by their unique ability to build calcium carbonate skeletons, forming coral reefs. These structures provide habitat and protection for countless marine species and play a crucial role in ocean ecosystems, showcasing symbiotic relationships with algae known as zooxanthellae.

5 Must Know Facts For Your Next Test

1. Corals are primarily composed of tiny polyps that live in colonies, each polyp feeding on plankton and small fish through their tentacles.
2. Corals thrive in warm, shallow waters where sunlight can penetrate, which is essential for their symbiotic relationship with zooxanthellae.
3. Coral reefs are often referred to as the 'rainforests of the sea' due to their high biodiversity, hosting thousands of marine species.
4. Coral bleaching occurs when stressed corals expel their symbiotic algae, leading to loss of color and potentially death if conditions do not improve.
5. Corals contribute to coastal protection by absorbing wave energy, helping to reduce erosion and shield shorelines from storms.

Review Questions

• Explain how the symbiotic relationship between corals and zooxanthellae benefits both organisms.
  • The symbiotic relationship between corals and zooxanthellae is mutually beneficial. Zooxanthellae live within coral polyps, providing them with essential nutrients through photosynthesis. In return, corals offer a protected environment and access to sunlight for these algae. This partnership not only supports coral growth but also helps sustain the entire reef ecosystem by promoting biodiversity.
• Discuss the impact of environmental stressors on coral health and the phenomenon of coral bleaching.
  • Environmental stressors such as rising sea temperatures, pollution, and ocean acidification significantly impact coral health. When corals experience stress, they may expel their symbiotic zooxanthellae, leading to a loss of color known as coral bleaching. This process reduces the corals' energy supply and can ultimately lead to their death if stressful conditions persist. Coral bleaching disrupts the entire reef ecosystem, threatening the diverse species that depend on healthy coral reefs.
• Analyze the ecological significance of coral reefs and the potential consequences of their decline on marine biodiversity.
  • Coral reefs play a vital ecological role by providing habitat, shelter, and breeding grounds for numerous marine species. They support around 25% of all marine life despite covering less than 1% of the ocean floor. The decline of coral reefs due to climate change, overfishing, and pollution could lead to significant loss of biodiversity. The resulting disruption in marine food webs would affect fish populations and other organisms that rely on healthy reefs for survival, further destabilizing ocean ecosystems.

Related terms

Coral Reefs: Large underwater structures made up of calcium carbonate secreted by corals, providing essential habitat for diverse marine life.

Symbiosis: A close and often long-term interaction between two different biological species, such as the relationship between corals and zooxanthellae.

Polyp:

The sessile, cylindrical form of a coral that attaches to substrates and is responsible for feeding and reproduction.