Updated by: Arabinda Naik
Overfishing: Another important worry is overfishing, which is causing an ecological imbalance in coral reefs.
Coastal development: Construction of coastal infrastructure and tourist resorts on or near these coral reefs causes substantial harm.
Pollution: Toxic chemicals that are discharged directly into the ocean can contribute to the poisoning of coral reefs by elevating the nitrogen concentration in the saltwater, thereby fostering an algal bloom.
Sedimentation: Building around the beaches and islands causes soil erosion, which increases sediments in the river. As a result, it can suffocate corals by preventing them from receiving the necessary light to survive.
Water Temperature: Water temperature is a critical factor for coral growth. Corals thrive in warm, clear waters, typically between 73° and 84° Fahrenheit (23° and 29° Celsius). Prolonged exposure to temperatures outside this range can cause coral bleaching, a phenomenon where corals expel their symbiotic algae, leading to loss of color and increased vulnerability to disease and death.
Salinity: Corals require stable salinity levels between 32 to 42 parts per thousand (ppt) for optimal growth and survival. Fluctuations in salinity, particularly sudden changes, can stress corals and disrupt their physiological processes.
Light Availability: Coral polyps rely on their symbiotic algae, zooxanthellae, for essential nutrients. Zooxanthellae require sunlight for photosynthesis, so corals need to grow in shallow, clear waters where sunlight can penetrate. Excessive turbidity or shading can hinder coral growth and lead to their decline.
Nutrient Levels: While corals require some nutrients, excessive nutrient runoff from land-based sources, such as agriculture and sewage, can harm coral reefs. Nutrient pollution can stimulate algae growth, leading to overgrowth that blocks sunlight from reaching zooxanthellae and smothering corals.
Sedimentation: Sedimentation, the deposition of fine particles like silt and sand, can smother corals and prevent them from receiving sunlight. Excessive sedimentation can also clog the pores of coral skeletons, interfering with their ability to absorb nutrients and build their calcium carbonate framework.
Ocean Acidification: Ocean acidification, caused by the absorption of carbon dioxide from the atmosphere, reduces the availability of carbonate ions in seawater, making it more difficult for corals to build their skeletons. This process can lead to slower coral growth and increased susceptibility to damage.
Ocean Currents and Wave Action: While some coral species can tolerate moderate wave action and currents, prolonged exposure to strong currents and storms can damage coral reefs and hinder their recovery. Storm-generated waves and surges can physically break apart coral colonies, while strong currents can dislodge coral fragments and hinder their reattachment.
Biological Interactions: Coral reefs are complex ecosystems with a variety of biological interactions that can influence coral growth. Competition for space and resources can occur between different coral species and other organisms, such as algae and invertebrates. Predation by fish, starfish, and other organisms can also affect coral populations.