Coral reefs around the world are doing it pretty tough as they face an onslaught of challenges, most of which are connected to human activity.
   
Warming seas can lead to bleaching events and carbon dioxide saturated oceans are becoming acidic and eating away at coral structures in some regions.
   
Pesticides also take their toll, even when they are present in extremely small levels. Back in 2007, I mentioned researchers had discovered some pesticides killed juvenile coral when present in water at just one part per billion. 
   
Another threat to emerge is human poop; or more accurately a bacterium called Serratia marcescens sometimes present in human excrement. 
   
Aside from coral reefs being an important part of tourism, injecting cash into local communities, corals such as Elkhorn provide a valuable marine habitat and used to be the Caribbean’s most prolific reef builder. 
  
The presence of elkhorn coral in the region has declined 90% over the past decade, due in part to white pox disease. White pox disease results in lesions that expose the coral’s skeleton, ultimately killing it. Coral in the Florida Keys region has also experienced outbreaks in the last decade.
      
In an experiment conducted by researchers from Rollins College and the University of Georgia, when exposed to the human-specific strain of Serratia marcescens, healthy elkhorn coral showed signs of white pox infection within as little as 5 days.
    
What makes this finding even more disturbing is it’s a case of “reverse zoonosis”. Zoonosis is a phenomenon where an infectious disease can be transmitted from non-human animals to humans. Additionally, this human-to-coral reverse zoonosis jumps the gap between land-based creatures and marine.
    
In the case of Florida Keys, septic tanks that leak sewage into the porous bedrock are thought to be a source of the bacteria. The scientists behind the research are hoping the conclusive results will encourage communities to upgrade sewage treatment. They note Key West hasn’t experience a case of white pox since its community made the switch to an advanced wastewater treatment facility some years ago.
    
Source: Rollins College and University of Georgia
     
Related:
     
Sewage wastewater treatment
Composting human waste – humanure
Your pee is precious