Marine Conservation
Volunteer and Adventure

The Disappearance of Coral Reefs: Causes and Consequences

GVI

Posted: March 4, 2023

Coral reefs are some of the world’s most vital and picturesque ecosystems, home to a large variety of marine life and a popular destination for scuba divers and other ocean enthusiasts. However, these reefs are under increasing threat of destruction due to a combination of human activity, natural occurrences, and climate change. To understand the current and potential future consequences of this decline, it is essential to thoroughly examine the various causes of coral reef decline.

Causes of Coral Reef Decline

There are numerous reasons why coral reefs are experiencing a decline in underwater health and abundance. Overfishing is one of the major threats to coral reefs, as commercial fishing operations often employ unsustainable practices that reduce fish populations in coral reefs. Additionally, climate change has impacted the temperature and chemistry of the water, making it difficult for the corals to survive.

Pollution from land-based sources such as industrial runoff, agricultural runoff, and sewage can also lead to coral reef decline. Nutrient pollution from this runoff can lead to an increase in algae that can outcompete corals for light and space and can cause diseases in coral larvae. Furthermore, plastic pollution and related issues such as coastal construction and dynamite fishing can have terrible consequences for the health of coral reef ecosystems.

Effects of Coral Reef Loss

The decline in coral reefs has numerous direct and indirect effects on the ocean environment and the surrounding communities. Coral reefs provide essential habitats for a variety of species such as fish, molluscs, sponges, and invertebrates, so their decline can result in decreased biodiversity in the area. Additionally, they absorb wave energy, which helps protect coastlines from storms, floods, and other natural disasters. Without healthy reefs, these areas are more prone to damage.

The economic impacts of coral reef decline extend to coastal communities relying on reefs for their livelihood. Many communities rely on reefs for tourism and fishing activities for food and employment. When corals are degenerated or lost, these activities are put at risk.

Overfishing and its Impact on Coral Reefs

The most immediate effect of overfishing on coral reefs is a decrease in the abundance of fish species that inhabit them. As commercial fishing aims to capture as much fish as possible, total populations suffer due to reduced reproduction rates and increased vulnerability to natural predators. Additionally, many fishing methods are destructive to the reef itself, such as bottom trawling, which stirs up clouds of sediment that smother corals.

In areas where fishing has become an excessively large problem, the entire food chain is disrupted. Predators such as sharks are no longer able to hunt their prey, which leads to an abundance of smaller species such as parrotfish that feed on algae. This can lead to algal overgrowth that smothers the corals.

Climate Change and its Impact on Coral Reefs

Climate change is causing numerous problems for coral reefs around the world. High water temperatures make it difficult for corals to maintain their essential symbiotic relationship with their zooxanthellae algae. Without these algae, corals bleach, lose their colour, and die off due to starvation.

In addition, ocean acidification has led to an increase in oceanic carbon dioxide levels over the last two centuries. Corals are particularly susceptible to low pH levels, meaning they may struggle to form calcium carbonate skeletons. The combination of high temperatures and low pH levels has already caused widespread destruction to coral reef systems.

Pollution and its Impact on Coral Reefs

Pollution from a variety of sources has profoundly damaged coral reefs in many areas around the world. Pollutants from human populations located near coastlines or rivers flow into the ocean, resulting in reduced overall water quality and destruction from sediment buildup. Nutrient pollution from this runoff can increase nutrient levels which can cause algal blooms that reduce light penetration for corals.

Excess nutrients can also stimulate an increase in disease outbreaks among coral populations. Organic pollutants such as heavy metals have been found in coral tissue following runoff from industrial sources, leading to further mortality and bleaching.

Fragment of colorful coral reef in the tropical sea

Solutions to the Problem of Coral Reef Loss

Fortunately, there are numerous steps that can be taken to help protect coral reefs before they become further depleted. The first step is reducing fishing pressure by tracking catch limits and fishing quotas, as well as implementing policies that regulate the types of fishing nets used in waters surrounding coral reefs.

Reducing runoff pollution is also vitally important; this can be done by creating buffer zones between industrial sites and the coastlines, utilizing more efficient agricultural practices such as crop rotation, requiring treatment for all sewage effluent, and instituting legislation that limits fertilizer use near water bodies.

The Role of Conservation in Protecting Coral Reefs

Conservation efforts are also an essential part of saving coral reefs. Marine protected areas have been established all around the world in order to protect reefs from fishing and other human activities. Additionally, regional mitigation measures have been put into place that seeks to reduce or reverse the impact of climate change on coral reef systems.

These efforts include both local sustainability projects such as restoring damaged coral colonies through transplantation as well as larger-scale attempts to address climate change. Ultimately, it takes an effort from both humans and nature to ensure the future health of these delicate ecosystems.

Economic Impacts of Coral Reef Loss

The economic impacts of coral reef loss can reverberate through entire communities that rely on these resources for their livelihoods. For example, fishermen may not be able to make a living if they cannot access certain reef habitats due to overfishing or other pressures. Tourism can also be deeply impacted by a decrease in reef health due to fewer visitors.

The loss of a productive reef also affects many other industries that rely on it for their supply chains, such as those that produce seafood or pharmaceuticals from reef-related organisms. This has a devastating ripple effect on any industries that rely on coral reefs for their production.

Helping Restore Coral Reefs with GVI

Approximately 50% of coral reefs around the world have bleached over the past three decades. This biodiverse species faces a true threat of extinction with the rise of global warming. GVI operates coral reef ecology and restoration projects in Mexico, Seychelles and Fiji. Join us to help save these essential ecosystems. You’ll work with an international team, you will undergo extensive training, designed to improve your skills and further your knowledge of the marine ecosystem.