Coral reefs, essential to marine biodiversity, are now threatened by factors such as global warming, pollution and overfishing. Protecting these fragile ecosystems requires a scientific and practical approach. In our Masterclass, you will discover the conservation techniques that can save these underwater jewels. Whether you are an ocean enthusiast or an environmental professional, this training will allow you to better understand and act to preserve coral reefs.
Coral in evolution
Corals appeared more than 500 million years ago. They have survived many climatic upheavals, but today, their resilience is being severely tested. Their role in the evolution of marine ecosystems makes them a central player for biodiversity, and their protection is essential for future generations.
Introduction to Coral Reef Ecology
What is a coral reef?
A coral reef is an underwater structure formed by colonies of corals that secrete calcium carbonate. These complex ecosystems are home to immense marine biodiversity, providing food and shelter to many species.
Where are coral reefs found and what types do they belong to?
Coral reefs occur in tropical and subtropical oceans, mainly between latitudes 30°N and 30°S. There are three main types: fringing reefs, barrier reefs, and atolls.
Aside on Cold Water Coral Reefs
Although less well known, there are also coral reefs in colder and deeper waters. These reefs, often located off the coast of Norway or Scotland, are vital habitats for several marine species.
Coral biology
How is a coral structured?
Corals are made up of thousands of polyps, individual organisms that form colonies. These polyps, with the help of zooxanthellae (symbiotic algae), build the limestone structure of the reef.
What is the anatomical structure of coral?
The polyp is a small animal with a mouth surrounded by tentacles, used to capture food particles. It lives in colonies, thus connecting several polyps to form the reef.
What is the role of polyps?
Polyps are responsible for the formation of the calcareous skeleton, a process that allows the reef to grow. They also play a crucial role in feeding the coral, capturing plankton and transforming sunlight through symbiosis with algae.
How is the calcareous skeleton of corals formed?
The calcareous skeleton is formed by the secretion of calcium carbonate by the polyps. This process allows the reef to grow and provide solid shelter for the many marine species that live there.
How do corals reproduce?
Corals reproduce sexually, by releasing gametes into the water, and asexually, by cloning polyps. Both mechanisms ensure the continuity and regeneration of coral reefs.
What is the symbiosis between corals and zooxanthellae?
Zooxanthellae are microscopic algae that live in coral tissue. Through photosynthesis, they provide energy to corals, which in return provide them with a safe habitat. This symbiosis is essential for the survival of reefs.
What factors influence coral growth and health?
Water temperature, acidity, light and available nutrients directly influence coral health. Climate change, in particular, poses a major threat to these ecosystems.
What is coral fluorescence?
Some corals have fluorescent pigments that allow them to glow under UV light. This phenomenon may be a response to environmental stress and helps protect corals from the harmful effects of sunlight.
The threats
What are the threats to coral reefs?
Global warming, ocean acidification, overfishing and plastic pollution are the main threats facing coral reefs.
Global and local threats
Globally, climate change is the greatest threat, while locally, factors such as deforestation, agriculture and unregulated tourism are worsening reef degradation.
Immersion in an Indonesian fishing village totally dependent on the coral reef
In some coastal villages, coral reefs are a source of life. This immersion will allow you to better understand the symbiotic relationship between local communities and these marine ecosystems.
Protection, conservation and management of coral reefs
What strategies exist for the conservation of coral reefs?
Strategies such as creating marine protected areas, reef restoration and reducing marine pollution are essential for reef conservation.
What is the role of marine protected areas in the conservation of coral reefs?
Marine protected areas limit human activities in certain areas, providing a safe environment for reefs to regenerate.
How is coral reef restoration implemented?
Restoration involves growing and reintroducing coral fragments into degraded reefs. This technique helps rebuild healthy marine ecosystems.
Immersion in the coral reef conservation program on Hatamin Island – Indonesia
On Hatamin Island, an innovative conservation program has been implemented to restore and protect coral reefs. This program will show you how local actions can have a global impact on reef health.
Scientific references
Hughes, TP, et al. (2018). Coral reefs in the Anthropocene . Nature, 546(7656), 82-90.
Hoegh-Guldberg, O., et al. (2017). Coral reef ecosystems under climate change and ocean acidification . Frontiers in Marine Science, 4, 158.
Moberg, F., & Folke, C. (1999). Ecological goods and services of coral reef ecosystems . Ecological Economics, 29(2), 215-233.
