Florida’s coral reefs have been declining alarmingly over the past few decades. Environmentalists have linked this phenomenon to global warming. However, a recent study shows that the real cause of the depletion is not global warming, but excessive nitrogen being dumped into the water.
Brian Lapointe, a professor at Florida Atlantic University (FAU), has collected 30 years of data about the region’s coral reefs. When he started his research in 1984, almost 33 percent of the Looe Key Sanctuary Preservation area was covered with coral. Thirty years later in 2014, the coral cover dropped to a shocking 5 percent. When he tried to understand the reason behind the coral decline, Lapointe discovered that excessive nitrogen was being dumped into the waters.
The nitrogen came from poorly-treated sewage and fertilizers from nearby farms. It messed up the water quality of the coral habitat by allowing algae to grow unchecked. The algae eventually blocked out sunlight and disrupted the nutrient balance in the water. This negatively affected the coral’s life cycle as the excessive nitrogen was not balanced by a proportional increase in phosphorus, which is necessary for the growth of the coral. As a consequence, the coral became unhealthy, got affected by diseases, underwent bleaching, and eventually died off.
Data shows that annual coral loss rose during periods of heavy rainfall when excess water traveled from the Florida Everglades into coral habitats, raising nitrogen and phytoplankton levels. In the future, the amount of nitrogen being deposited into the coast is expected to increase by 19 percent due to a rise in rainfall. By controlling the flow of nitrogen-rich water, the coral habitats can be kept safe from further degradation.
“The future success of the Comprehensive Everglades Restoration Plan will rely on recognizing the hydrological and nitrogen linkages between the Everglades, Florida Bay, and the Florida Keys… The good news is that we can do something about the nitrogen problem such as better sewage treatment, reducing fertilizer inputs, and increasing storage and treatment of stormwater on the Florida mainland,” (Science Daily).
Keeping coral reefs alive
One way to keep the coral reefs safe is through a technique called “assisted evolution.” The method is being put to use by a team of scientists working in the Florida Keys. They broke off a few pieces of coral and submerged them in acidic water tanks. The coral that survived is then attached to artificial trees underwater. Once they grow to a certain extent, they are transplanted back to the reef.
“It has already made a difference… There are places that have not had branching corals in 30 years and now you go out and look at the bottom and say: ‘Wow, this is starting to look like it used to,’” Mark Eakin, coordinator of the Coral Reef Watch project at the U.S. National Oceanographic and Atmospheric Administration, said to the Los Angeles Times.
Another method, called “cloud brightening,” involves pumping seawater through a filter and spraying it toward the clouds using a fan. The water will evaporate, but salt particles present in the water remain. These particles will then condense with other water in the atmosphere and make the clouds brighter, which then deflects the sun’s rays and keeps the oceans cooler. As a result, the coral will stop bleaching and dying off.