Public perception of fertilizer and Florida red tides

Background: Harmful algal blooms (HABs) are accumulations of certain species of marine or freshwater algae that produce natural toxins that may cause morbidity and mortality in exposed animals and humans. In the eastern Gulf of Mexico, Karenia brevis (also known as “Florida red tide”) is the most common marine HAB. A possible but unproven cause of coastal blooms of Florida red tide is the release of macronutrients, nitrate and phosphate, though the runoff of fertilizers from agriculture, golf courses, and agricultural and residential lawns and releases of treated wastewater, and septic system and combined sewer overflows.

Methods: This study evaluated the reported knowledge, attitudes, and behaviors of 61 adult residents of Sarasota County, Florida towards HABs and nutrients in a coastal community regularly affected by blooms of Florida red tide. Notably, this community has begun to institute local nutrient-restriction policies including a municipal ordinance regulating lawn fertilizer applications.

Results: The study population was knowledgeable about Florida red tides but had relatively little understanding of the existence or the purpose of local nutrient-restriction regulations. Those respondents who knew about the regulations assumed an established scientific causal connection between fertilizers (nutrients) and Florida red tides, acting accordingly with regard to fertilizer use.

Conclusions: This study demonstrates gaps between public perceptions, the state of the relevant science, and the implementation of public policy. Given the apparent misconceptions, future studies should be performed to determine the effectiveness of current policy on HAB prevention due to the need for public approval and adherence to regulations.