Our marine ecosystems are being impacted by increasing carbon dioxide and other greenhouse gas emissions from human activities. As a result, ocean temperatures and acidification have led to rising sea levels, reduced marine diversity and species abundance.
Historically, our oceans have served as a major transportation network, a source of food and a favourite recreational area for thousands of years. This degradation of coastal and marine ecosystems threatens the physical landscape, economies and food security of communities, as well as resources for global businesses.
Why is the marine environment so important?
Besides covering more than 70% of the surface of our planet, the marine environment plays a central role in regulating global temperature, as it is the primary producer of oxygen and many other key environmental functions.
Just as trees absorb carbon dioxide through their leaves, the ocean forms an incredible carbon sink that stores atmospheric carbon. However, this becomes less efficient with increasing global emissions.
Why are coral reefs so significant?
Corals are made up of tiny animals called ‘polyps’ (which are related to jellyfish!), and are found among reef ecosystems, providing a home for thousands of species underwater.
Coral reefs play a significant role in sequestering carbon, as they are major carbon sinks. Globally, corals are capable of storing between 70 to 90 Mt of carbon per year (this is the equivalent of the emissions of over 11,000 homes for a year).
A hypothetical world without coral reefs
To put it simply: as more carbon dioxide is absorbed into the ocean, the water becomes more acidic, and the ability for corals to absorb carbon is greatly reduced. As a result of this, the corals are unable to strengthen their skeletons and the overall health of reef ecosystems declines.
Increased greenhouse gas levels have led to what is known as mass bleaching in coral reef ecosystems - one of the greatest threats to marine environments. This phenomenon results in increased coral vulnerability to diseases which impacts species reproduction and sees declining coral numbers. As the state of coral reefs decline, the surrounding marine ecosystems supported by them are also lost.
Unsupported marine habitats can result in a collapsing fishing industry and moreover, as coral reefs die, they release stored carbon back into our atmosphere, further worsening the problem.
Hope for the Future
Although the possibility of losing coral reefs is becoming more apparent with increasing environmental stressors related to climate change, not all hope is lost.
Researchers and scientists are proactively looking for ways to protect corals. Coral nurseries have been designed to repopulate damaged reefs in a protected environment, in the hope to help corals recover from bleaching events and improve the health of the current global coral ecosystem.
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