Different Threats to Coral Reefs

- SDGs14: Life Below Water -

Coral reefs are mesmerizing underwater ecosystems known for their vibrant colors, diverse marine life, and immense ecological importance. Despite their beauty and significance, coral reefs around the world are under severe threat. This essay explores the various factors contributing to the degradation of coral reefs, highlighting the urgent need for conservation efforts. The information presented here is sourced from reputable scientific publications and reports, including the National Oceanic and Atmospheric Administration (NOAA) and the Intergovernmental Panel on Climate Change (IPCC).

The Threats

One of the greatest threats to coral reefs is climate change, specifically the rising sea temperatures caused by global warming. The increased temperatures lead to coral bleaching, a phenomenon where corals lose their symbiotic algae, turning them white and vulnerable to disease and death. According to the IPCC's Fifth Assessment Report, coral bleaching events have become more frequent and severe in recent decades (What’s in It for Small Island Developing States?). Moreover, the report states that without immediate action to reduce greenhouse gas emissions, the majority of coral reefs could disappear by the end of the century.

Fig 1. Climate change impact on coral reefs

Additionally, climate change contributes to ocean acidification, a process in which carbon dioxide from the atmosphere dissolves in seawater, resulting in a decrease in pH. Acidic conditions inhibit the ability of corals to build their calcium carbonate skeletons, hampering their growth and survival. NOAA's Coral Reef Conservation Program indicates that the increasing acidity of oceans poses a significant threat to coral reefs and the entire marine ecosystem (Ocean Acidification).

Pollution, both from land and sea-based activities, has a detrimental impact on coral reefs. Excessive nutrient runoff from agricultural practices and sewage discharge can trigger algal blooms, leading to reduced water clarity and suffocating corals. The accumulation of sediments, chemicals, and heavy metals in the water further exacerbates the problem.

In particular, the use of harmful chemicals, such as pesticides and fertilizers, in agricultural and residential areas can contaminate nearby water bodies, eventually reaching coral reefs. These pollutants compromise the health and reproductive success of coral species, contributing to their decline.

Fig 2. Pollution on coral reefs

Overfishing is another significant threat to coral reef ecosystems. Unsustainable fishing practices, including dynamite and cyanide fishing, result in the destruction of coral habitats and the depletion of fish populations. When explosive devices are used, the shockwaves harm corals, fragmenting and killing them. Cyanide fishing involves squirting cyanide into the water to stun fish, but it also damages coral reefs.

Removing key fish species from the ecosystem disrupts the delicate balance of coral reef communities. For instance, the loss of herbivorous fish, such as parrotfish and surgeonfish, can lead to an overgrowth of algae, smothering corals and impeding their growth. The World Wildlife Fund (WWF) warns that overfishing threatens the resilience and ability of coral reefs to recover from other stressors (Overfishing is jeopardizing our oceans).

Human activities, particularly coastal development, and physical destruction, pose a direct threat to coral reefs. Construction of harbors, marinas, and resorts near coral reef areas often involves dredging and the removal of coral colonies. These activities not only destroy coral habitats but also increase sedimentation and pollution in surrounding waters.

Moreover, the extraction of coral for building materials, jewelry, and curios has a devastating impact on reef ecosystems. The removal of coral colonies disrupts the delicate structure and reduces the overall biodiversity of the reef. The United Nations Environment Programme (UNEP) estimates that around 50% of the world's coral reefs are already severely damaged or lost due to human activities (Protecting Coral Reefs).

Concluding Remarks Coral reefs, the rainforests of the sea, face an array of threats that jeopardize their very existence. Climate change, pollution, overfishing, and coastal development collectively contribute to the ongoing degradation of these invaluable ecosystems. To preserve and protect coral reefs for future generations, immediate action is necessary. Efforts to reduce greenhouse gas emissions, regulate pollutant discharge, promote sustainable fishing practices, and establish marine protected areas are crucial steps toward safeguarding coral reefs. As stewards of the planet, it is our responsibility to prioritize the conservation of these fragile ecosystems and work towards a sustainable future.

References:

https://coralreef.noaa.gov/gallery/infographic/Ocean_Acidification.html https://www.worldwildlife.org/magazine/issues/fall-2019/articles/overfishing-is-jeopardizing-our-o ceans https://www.unep.org/explore-topics/oceans-seas/what-we-do/protecting-coral-reefs https://cdkn.org/sites/default/files/files/IPCC-AR5-Whats-in-it-for-SIDS_WEB.pdf https://thebulletin.org/2016/10/a-changing-climate-for-coral-reefs/ (fig 1) https://www.npr.org/sections/thetwo-way/2018/01/25/580227045/plastic-pollution-is-killing-coral- reefs-4-year-study-finds (fig 2)