Can Nitrogen Have a Devastating Effect on Coral Reefs?

A diver swimming over elkhorn coral in the Florida Keys

When most people think of climate change devastating the world's coral reefs, the first thing that comes to their mind is the increase in water temperature that contributes to coral bleaching. However, there are other factors that affect coral reefs as well. One of those factors is nitrogen. This was recently discovered in the research of Brian Lapointe, a professor at Harbor Branch Oceanographic Institute in Florida Atlantic University, who had been studying corals at the Looe Key Reef in the Florida Keys National Marine Sanctuary since the 1980s. Dr. Lapointe initially thought that his study would show that rising temperatures were decimating the corals, but instead, his data indicated that nitrogen is the source of destruction. It has been found that increase in nitrogen from crudely treated sewage, along with fertilizer and topsoil from farms and yards, is messing up the quality of water in the coral habitat. Excessive nitrogen feeds algae blooms that obstruct light and throws off nutrient balance in the water in ways that disturbs the coral's life cycle. According to Dr. Lapointe, since the nitrogen has gone up, it has not been balanced by a similar increase in phosphorus which the corals need to grow. This imbalance is refraining the corals of phosphorus. He further added that the imbalance makes the corals unhealthy, and more prone to disease and coral bleaching. According to James W. Porter, emeritus ecology professor at the University of Georgia and co-author of a recently published paper by Dr. Lapointe, the new study indicates that water quality and not just temperature are essential for coral survival. This is seen as coral die-offs occurred long before high water temperatures reach the reef. Dr. Porter further added that the research shows that coral reefs can be protected by taking care of nutrients on the reef and runoff from the land. Furthermore, the findings not only apply to the corals of the Florida Keys, but around the world, including the Great Barrier Reef, which is known to receive runoff from Queensland's sugarcane fields. The authors of the study stated that improved sewage and storm-water management can mitigate nitrogen pollution.

A dying brain coral in Looe Key

I think it is very important to take note of this latest research, which shows that there are several factors that contribute to the devastation of coral reefs around the world. One of those factors is nitrogen, which affects the reefs when entering the waters in large quantities from sewage, fertilizers, and topsoil from farms and yards. In the process, the nitrogen fuels algae blooms that block light from reaching the corals thus resulting in nutrient imbalance that disturbs the corals' life cycle making them susceptible to disease and coral bleaching. I strongly believe that concerted efforts need to be made on a global scale to prevent any further devastation of the world's coral reefs. This includes properly managing sewage and fertilizers to minimize nitrogen pollution. In addition, emphasis need to be put on mitigating runoffs from mainland and into the seas. One example of a coral reef success story was seen in 2011 when the coral reefs of Bonaire in the Caribbean began to recover after a new sewage treatment plant opened that year. I really think that people should look at such examples and learn from them, in order help save the world's coral reefs. Many of these reefs provide food, shelter, and other amenities to the marine life and without them, marine life would be decimated.

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