Above: NOAA’s 5 km Experimental Current and 60% Probability Coral Bleaching Alert Outlook Areas through September 2016. Updated July 24, 2016. According to recent reports, the Florida Keys are experiencing a moderate threat of bleaching to local corals. http://coralreefwatch.noaa.gov/vs/gauges/florida_keys.php

By: Chayse Moehrke

When most of us think of summer, we are thinking of things such as barbeques, beach days, and fun in the sun. Unfortunately, for corals, summertime isn’t always this much fun; coral reefs face many heightened stressors during the summer and corals in particular are prone to stressors that may cause extreme deterioration in their health. Two of the concerns that come to our minds at Coral Restoration Foundation are outbreaks of coral bleaching and coral disease.

Coral disease caused by both abiotic and biotic sources are a subject of much discussion for those concerned with coral reef health, management, and recovery. Many studies are finding strong correlations between the rising water temperatures and an increase in the amount of disease plaguing corals during warmer summertime months. A rise in temperature can be considered a pathogen if it harms and alters the way an organism functions. In the case of the coral bleaching, rising- or decreasing-water temperature outside of the coral’s normal range can cause zooxanthellae to be expelled or die within the coral tissues. Zooxanthellae provide 90% of the coral’s nutrient uptake and without this algae, the coral suffers a slow starvation that can lead to death more often than not due to the extremity and length of increased sea surface temperature events. According to Cory Walter, “the initial onset of mass coral bleaching can vary among different species, geographic locations, types of reef zones and a fluctuation of severity, which makes it very difficult to predict where or when it will occur.” Scientists around the world need to have a better understanding of the coral bleaching phenomenon that occurs. In order to monitor bleaching events, Mote created a program that would help with this goal.

Mote Marine Tropical Marine Laboratory, a fellow partner of Coral Restoration Foundation and restoration group in the Florida Keys, developed a coral bleaching monitoring program titled “The Florida Keys BleachWatch Program”. The program was created in collaboration with the Florida Keys National Marine Sanctuary in reflection of the Great Barrier Reef’s BleachWatch program. It consists of a variety of staff and volunteer divers who help observe and report the conditions of different reefs. After diving on a reef, the divers complete a data form and send it to the BleachWatch coordinator. The coordinator condenses this data to create A “Current Conditions Report, that is available to the public monthly, weekly, or biweekly depending on the severity of the bleaching event. This report generates information for coral bleaching threat levels, which help keep managers and the general public informed about reef conditions during the summertime (and wintertime when applicable). Currently, our reefs are under a “watch” threat level, indicating that conditions for coral bleaching are likely to occur over the next few weeks.

When we think of disease, most people, including myself until recently, think of bacteria and viruses that make animals sick. Scientifically speaking, a disease is defined as any impairment of an organism’s vital functions that can be caused by both biotic and abiotic sources; biotic refers to living sources such as bacteria or pathogens, while abiotic refers to nonliving sources, like temperature, light, or salinity. This definition means that “disease” can arise due to a pathogen or virus, but it can also arise due to extreme fluctuations in temperature, water quality, light, pollutants, and even physical damage to an organism. Applying this to coral health, it becomes clear that coral bleaching is in fact a “disease”. Crazy, isn’t it? To learn more about coral bleaching prevalence on Florida Keys reef or participate in coral bleaching surveys, check out the Mote Coral BleachWatch page here: https://mote.org/research/program/coral-reef-science-monitoring/bleachwatch.



Walters, Cory. Mote Marine Laboratory / Florida Keys National Marine Sanctuary- Florida Keys BleachWatch Program Overview. https://mote.org/media/uploads/meera/BW_project.pdf. 2016.