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Coral Reefs and Wastewater

In the majority of the world sewage is not treated at a wastewater treatment plant.  Instead, it typically finds its way into our oceans as poorly treated or untreated discharge or as storm water run off.  In many countries, due to the lack of infrastructure, sewage is directly discharged into the sea.

Coral and Seaweed often fight for dominance and with an overload of nutrients from wastewater, the herbivorous marine life inhabited in coral systems cannot overcome the growth of seaweed.  Seaweed overgrowth can have significant impacts on coral as they both fight for sunlight.  

Nutrient overloading isn't the biggest issue however, as wastewater provides a list of challenges for coral reefs to overcome.

Fresh water:  At the most basic level, the primary component of sewage is fresh water. Too much fresh water can stress and even kill coral.  Many studies have shown that influxes of fresh water increase reef mortality.

Pathogens: Sewage is filled with viruses and bacteria, and fecal contamination.  Serratia marcescens, for example, which causes white pox disease, killed more than 70 percent of corals in the Florida Keys.

Toxins:  Human beings consume many different types of pharmaceuticals that end up in our sewage. Antibiotics, for example, are especially problematic for corals which have a protective mucus layer that is home to a diverse community of bacteria that function much in the same way as the microbes in our intestines. Scientists suspect that antibiotics may impact this bacterial community, which makes the corals more susceptible to disease.

Endocrine disruptors: Found in many household products, these chemicals disrupt the hormone system in both humans and other living things. They include natural and synthetic estrogens, parabens, petrochemicals, and phthalates, among others. 


Heavy metals: These chemicals — including mercury, lead, and copper — can lead to bleaching, death, and decreased reproductive success in corals.  Heavy metals will accumulate in the skeletons of corals and also increase the strength of pathogens on the coral’s surface, making the coral susceptible to infection.

The bottom line is that dumping wastewater into our oceans and seas is causing irreparable harm to our coral, and marine eco systems.  We must utilize innovative, economical, energy efficient technologies to treat and continually reuse our water without sending it to our precious oceans and seas.

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