By, Rudy Bonn, Reef Relief’s Director of Marine Projects
On Wednesday, August 31st, I had the privilege to meet and dive with Dr. James Porter from the Odum School of Ecology, University of Georgia, Athens, Georgia. Dr. Porter was accompanied by Meridith Meyers, a PhD student who is doing her work on the genetics of coral species in the genus, Agaricia.
Dr. Porter and a number of fellow researchers were the first to link a devastating disease in the threatened Elkhorn Coral, Acropora palmata, to a unique strain of a bacterium known as Serratia marcescens, strain PDR60, that is an opportunistic pathogen found in human waste.
The disease, known as acroporid serratiosis ( APS ), commonly referred to as white pox, has devastated the elkhorn coral populations in the Florida Keys, and was the main reason why the coral was listed for protection under the Endangered Species Act ( ESA ) in 2006.
White Band Disease ( WBD ), another coral killer, is mainly responsible for the high mortality that the staghorn ( A. cervicornis ) coral populations have suffered in recent years and the etiology of WBD is still unknown. Both corals are listed as threatened under the ESA.
What is also very important about the research that Dr. Porter and colleague, Dr. Kathryn P. Sutherland, of Rollins College, in Winter Park, Florida, have discovered is the first example of a marine “reverse zoonosis” involving the transmission of a human pathogen to a marine invertebrate. Their findings underscore the interaction between public health practices and environmental health indices such as coral reef survival
The effluent from the Fleming Key Wastewater treatment plant was tested by Dr. Porter and the bacterium was not found, so where is the source
Water quality is one of the biggest issues and concerns here in Monroe county. E. coli outbreaks are a common occurrence, as we all know when we read the health advisories in the Citizen every week. E. coli is another enteric bacterium found in the intestinal tracts of warm-blooded animals, not iguanas- a cold-blooded animal- as so many people here think, that is an impossibility and comes from disinformation being generated by misinformed people.
The sources of these pathogens are many: Leaking septic systems, cesspits, storm water run-off, even waters that reach the keys from as far away as the Mississippi Delta via loop currents in the GOM can bring pathogens and nutrients to our near-shore waters, and there are many others, ocean outfall pipes still being used in Miami and Palm Beach for example, among others!
The challenges are many, and the work needs to be broad and comprehensive in scope if we are to save our coral reefs.
Climate change, especially rising water temperatures, and its evil twin, ocean acidification, along with over fishing, and pollution are the three biggest threats to coral reef ecosystems world wide and are working in synergy against the corals. The coral reefs of the world are being attacked by a multitude of stressors simultaneously, and cannot keep ahead of the onslaught in terms of evolutionary adaptability—the pace of the present onslaught is unprecedented in the history of the natural world.
On our dives we were fortunate not to encounter any white pox, but we did witness bleaching in almost every colony. Bleaching occurs when corals reach their thermal thresholds, hot or cold, and leads to the coral expelling its symbiotic algae partner known as zooxanthelle
The algae are an endosymbiont of the corals and reside in the cells of the coral’s tissues. It produces food for the coral in the form of a carbohydrate produced through photosynthesis, and is why reef-building corals are found in clear, nutrient-free tropical waters. The alga cells also contain pigment and are what gives corals their bright color
Bleaching is a stress response, the photosynthetic process is interrupted at the molecular level and the alga cells actually begin producing radical oxides which are poisonous to the corals. The corals expel their colorful partners and turn a ghostly white, thus the term, bleaching.
Corals can survive for a limited time but will succumb if the alga cells are not replaced within a couple of weeks or so depending upon species- some being more resilient than others. Science has found more resistant strains of the algae, but successfully inoculating other corals is still in the research stages as these alga cells seem to be species specific in terms of their coral hosts
What can we do? What are our choices in terms of mitigating these challenges. There are lots of things we can do: the reduction of carbon dioxide emissions would be an enormous first step in the battle against climate change. Commercial and recreational fishing can be managed in such a way that all parties involved derive benefit, and pollution, we have to stop treating our oceans, rivers, and lakes, as garbage dumps.
Reef Relief runs Coral Camp for kids every summer and one of the things I have to tell them is that there is the possibility that their children might not get the opportunity to see a living, vibrant, coral reef right here in the Keys. That we are leaving their generations with all these challenges, but you know what, from what I gather from these small kids, is that there up to the challenge and want to save the coral reefs.
Dr. Porter and colleagues also want to thank members of the media for the sharing of this important information. It is vital that people realize the urgency that is needed if we are going to save our reefs– the cascading effects throughout marine ecosystems that would occur if this were to happen is not a pleasant thing to contemplate as there would be a mass extinction throughout the marine environment involving most metazoan phyla– an event never witnessed by modern humans and to think that we might be the first is very unsettling.
Dr. Porter’s and Dr. Sutherland’s important work was funded through grants from the National Science Foundation and the National Institutes of Health.