In 2013, there were four major problems with water quality in the Indian River Lagoon. 1) Excess nitrogen and phosphorus from runoff from the application of fertilizer; 2) an estimated 8 to 11% septic tank failure. There are tens of thousands of septic tanks in the county. 3) Muck from construction, farming, erosion and dead plants, all find their way to the bottom of the lagoon, preventing growth and consuming vital oxygen essential to marine flora and fauna; 4) Invasive species, including the Asian green mussel, South American charru mussel, and the Australian spotted jellyfish, all eat clams and fish larvae.