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Indian River Lagoon Trivia

Our Indian River Lagoon is facing challenges that grow daily. This quiz is designed to test your understanding of one of the nation's greatest treasures and the most important natural asset in the state of Florida. Thank you to Heather Stapleton with One Lagoon for contributing this important information.

What kind of water is in the Indian River Lagoon?

a. Fresh

b. Salt

c. Hot

d. Brackish

A: Brackish. Despite the word “river,” the IRL is an estuary – a place where saltwater and freshwater mix.

The answer is D

Brackish. Despite the word “river,” the IRL is an estuary – a place where saltwater and freshwater mix.


How many miles long is the Indian River Lagoon?

a. 40 miles

b. 56 miles

c. 86 miles

d. 156 miles

The answer is D

156 miles. The Indian River Lagoon spans 5 counties in east central Florida (Volusia, Brevard, Indian River, St Lucie and Martin Counties) and touches the northern boundary of Palm Beach County.


The Indian River Lagoon is not a river.

a. True

b. False

The answer is A

True. Despite the word “river,” the IRL is an estuary – a place where saltwater and freshwater mix. A river flows in one direction. The IRL is a wind driven system. It may flow north one day and the next day it may flow south. Or, it might be stagnant and not flow at all. The wind creates the lagoon’s direction of flow. Lagoons are shallow estuaries separated from the ocean by barrier islands. Lagoons have limited exchange with oceans.


Approximately how many species of plants and animals have been documented occurring in the IRL?

a. 100

b. 400

c. 4000

d. 1 million

The answer is C

4,000 species. Because the IRL is so long, it straddles the temperate and subtropical zones making it one of the most biological estuaries in North America.At its southern end, The Atlantic Gulf Stream hugs Florida’s shoreline and scientists believe this connection contributes to the large number of species of fish. Temperate, subtropical, and tropical species can be found.


What is the economic value of the IRL?

a. $1.7 million

b. $1.7 billion

c. $3.5 billion

d. $7.6 billion

The answer is D

Beyond its biological diversity, the lagoon is also a major economic engine for the region. A 2016 Economic Evaluation of the IRL by the Treasure Coast and East Central Florida Regional Planning Councils estimated that the total annual value of the IRL to be $7.6 billion.


Because of the inlets, pollutants have an opportunity to get flushed out of the lagoon.

a. True

b. False

The answer is B

False. Lagoons are fragile and vulnerable to changes in freshwater and pollutant loads. What goes in the lagoon often stays in the lagoon. This vulnerability is due to its physical, hydrological, and biological nature. The Indian River Lagoon is shallow, narrow, poorly flushed from the 5 inlets and influenced by a watershed that has been vastly changed by human population growth, land-use changes, water diversions and coastal development over the past century.


When properly designed, installed and maintained, approximately how much Total Nitrogen (TN) and Total Phosphorous (TP) does a traditional septic tank remove?

a. 90% TN and 25% TP

b. 75% TN and 25% TP

c. 34% TN and 50% TP

d. 34% TN and 10% TP

The answer is D

34% TN and 10% TP. Water quality issues arise when septic systems pass their useful life expectancy at around 20 years, when they are poorly designed or sited, and when clusters of septic systems are placed in densities that exceed the treatment capacity of soils. Older septic systems and those sited near the lagoon or close to a high-water table are of particular concern. Septic systems location in proximity to the lagoon or where the water table is high may intersect the water table before the tank effluent percolates through the soils, so little, if any treatment is achieved. Nutrient and bacterial contamination are serious problems. Excessive nitrogen and phosphorous in the lagoon fuel algal growth setting of a chain reaction.


What are actions that homeowners can take to help reduce nutrients carried to the lagoon by stormwater runoff?

a. Limit use of umbrellas

b. Plant Lagoon Friendly landscaping

c. Limit use of chemicals on lawn

d. b & c

The answer is B

As impervious surfaces (roads, sidewalks, rooftops) increase, so does stormwater. Stormwater runoff comes not from a single source, but from all of the land that drains into the lagoon. Stormwater runoff carries a wide variety of pollutants that increase nutrient loads and contribute to muck formation, chemical contamination, algal blooms and fish kills. Since 2011, the lagoon has suffered from multiple algal blooms. Lagoon friendly landscaping, minimal use of lawn products (especially during the rainy season), picking up after pets and controlling grass clippings can help reduce contamination


What leads to Harmful Agal Blooms?

a. not enough nutrients in the water

b. too many nutrients in the water

c. droughts

d. too much saltwater

The answer is B

Microscopic algae are always present at low levels and form the base of the lagoon’s complex food web. Microalgae feed on nutrients in the water much the same way landscape plants use fertilizer. When food supplies are adequate, algae grow and reproduce on a limited basis. However, when excess nutrients are present algal growth can become explosive. These intense and sometimes persistent blooms are called Harmful Algal Blooms (HABs) and block out sunlight to seagrass on the lagoon bottom, sometimes they can even become toxic (toxic HABs).


Find More Treasure Coast Trivia HERE


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