Coral reefs have been in the news a lot lately because they are under threat from ocean acidification, climate change (and this summer’s nasty heatwave), overfishing, coastal development, and more. Many people don’t understand why coral reefs are so important, which is why we asked an expert to help explain why coral reefs are so important and what threats they are facing.
Stephanie Wear is a marine scientist with The Nature Conservancy’s Global Marine Team. Her work has mainly focused on working with coral reef managers to identify ways to respond to the impacts of climate change. She is currently focusing on improving tools that assist in building resilience in coral reef communities. Here is our Q&A with her:
Why are coral reefs so important?
Coral reefs are important for ocean health and human communities that live nearby. Coral reefs are home to 25 percent of the animals and plants that live in the ocean. They provide feeding grounds, nursery areas, living space, and places to hide from predators for an enormous assortment of fish and invertebrates like grouper and lobster. For humans, corals provide food and jobs, with more than 500 million people dependent on reefs for their primary source of protein. In places like the Caribbean, a key component of the economy is tourism, which depends heavily on healthy coral reef communities. Coral reefs also provide coastal protection by buffering wave energy and are also a source of countless medicines that are improving and saving lives every day.
What is the status of coral reefs worldwide right now?
Corals are in decline globally. The combination of heavy fishing pressure, coastal development, pollution, and climate change are degrading reefs at a rapid pace. We have already lost about 20 percent of coral reefs worldwide with another 15 percent in critical condition.
What are the biggest threats facing coral reefs right now?
The biggest threats are over-fishing, coastal development, pollution, and climate change. It might be obvious to some that pollution would be bad for reefs and the sediments that end up in the water due to bad land practices smother reefs, but fishing has a huge effect by disturbing the ecological function of a reef. People across the globe have done a pretty good job of fishing down the food chain, first removing predators and now herbivores. In fact, there are many places in the world where bite-size reef fish are taken because they provide flavor for a soup – the big fish are just gone. These fish play an important role in maintaining a coral reef, especially the herbivores such as parrotfish who have the job of eating all the algae (or seaweed) that would otherwise smother and overgrow coral animals. If the herbivores are gone, and in many places they are, then the reefs can turn into algal reefs and most of the important values of a coral reef are completely lost.
How is climate change affecting coral reefs?
Climate change is affecting reefs at a global scale and the trends are alarming. The biggest effect of climate change on coral reefs is the warming of the oceans. Coral reefs, like all animals, have a certain range of temperature in which they can live. In the case of coral reefs, the range is fairly small and in many places around the world, especially this year, the upper limit to that range has been exceeded. During hot summers, corals are at risk for bleaching, especially if the heat wave lasts for an extended period or is particularly warm. When a coral bleaches, basically it has lost all the tiny algae cells in its tissues that give it color. These tiny plants are called ‘zooxanthellae’ (pronounced ZOE-ZAN-THELLY) and they come in all sorts of colors and are responsible for the brilliant blues and purples and pinks that you see on a coral reef. Once a coral bleaches, if it doesn’t reabsorb the zooxanthellae fairly quickly, it will die. We have seen mass bleaching events with significant mortality in the last decade and think we might be in the midst of one this year.
What can be done to mitigate these effects?
The single most important strategy for the future of coral reefs is to reduce the amount of climate change that occurs. Preventing massive damage to ecosystems on a global scale cannot be done without reducing greenhouse gas emissions and taking steps to slow down global climate change. In the meantime, we can do a better job of reducing the other threats to coral reefs so that they are poised to cope with changing conditions – effectively boosting their immune system so they can cope with stress. This can be done by increasing protection through effective protected areas, both on land and in the sea, and minimizing human impacts on coral reefs by limiting fishing, better coastal zone planning, and not tolerating ocean pollution.
Land conservation covers a much bigger area than ocean conservation. How could increasing the number of marine parks in the world help protect coral reefs?
It is important to note that coral reefs benefit from land protection when that land is near the coast. Many reefs are in a degraded state because of poor land use practices and faulty or absent sewage treatment systems. That said, the more area of ocean protected, the more likely that reefs will survive into the future and continue to be valuable resources for people. The Nature Conservancy is focusing on increasing the area of reef protected through more strategic protected area networks. These networks take climate change into account in their design and spread the risk across the network by including multiple examples of different reef types distributed over a large area.
What can be done to increase awareness with the public for the need of ocean conservation?
It is really important to remember that coral reefs are one of the first habitat types that are demonstrating a very visible response to the impacts of climate change. They won’t be the last; right now we have a chance to do something for the oceans and the world to reduce the impacts of climate change and ultimately limit the amount of change we experience. Corals are giving us a warning and we need to listen. The public needs to better understand the critically important role the oceans play for life on earth. The oceans actually make planet Earth habitable for humans by producing 50 percent of the oxygen we breathe! The oceans provide us with jobs, food, medicines, and more and more, people are moving to coastal areas. We need healthy oceans and we need to understand that as large as it is, the ocean is not infinite. Now our job is to show people how they are connected to the oceans and then how what they do every day impacts the oceans. We need healthy oceans and what we are experiencing with coral reefs now is only the beginning if we don’t start making big changes in the way we live our lives and take care of the natural resources we depend on.