Treasure Coast - Monday July 24, 2023: A new study has concluded that sewage, not fertilizer run-off, is the primary polluter of the Indian River Lagoon, underscoring the need for converting from septic tank use, to sewer systems.
The study was led by Dr. Brian LaPointe at Florida Atlantic University's Harbor Branch Oceanographic Institute in Fort Pierce. The research began in 2011. He describes the project as the first Indian River wide study of the nutrient content in Lagoon water, from the New Smyrna inlet in the north to the Jupiter Inlet in the south.
“We had 20 sites spanning that 156-mile length of the Lagoon where we looked at the composition of the water," said Dr. LaPointe. One of the principal goals of the study was to determine the effectiveness of fertilizer bans.
A key feature was the use of isotopes to identify the source of the nitrogen driving the algae blooms.
"What we found was that the nitrogen isotopes went up, they increased, telling us that there was more and more waste-water involved in driving these algae blooms that were causing the catastrophic loss of sea grass that is critical food for the Florida Manatee.”
In particular, the study compared the samples taken before the summer fertilizer black outs went into effect and samples taken after the bans were implemented. “What we found was that the blooms actually got worse through the course of this long-term study, despite these summer blackout ordinances.”
The results, said Dr. LaPointe, are further evidence of the need to end the use of septic tanks and convert to sewer systems along the Lagoon.