Caves, Springs, and Sinks

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Caves, Springs, and Sinks

• ENV 401 The Real Florida

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Why are Springs important?

• Supply of freshwater
• Aquifi-a-a-a-r

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Some facts

• Over 750 springs in Florida (actually 320)
• Discharge 12,300 cubic feet/second or 8 billion
  gallons/day (7.5 billion gallons of freshwater
  used each day in Florida)
• Can be classified based on
• Discharge
• Water temperature
• Chemistry
• Aquifer

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How do they form?

• Florida underlain with limestone and dolomite
  (see my demo rock)
• Heres the equation!!
• CaCO3 H2O CO2?CaCO3 H2CO3 (Carbonic Acid) ?
  CaCO3 HCO3- H

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Sinkholes

• Areas where underlying limestone has caved in

Recent sinkhole San Felasco State
Reserve, Alachua County
Devils Millhopper State Reserve, Alachua County
Devils Millhopper State Reserve, Alachua County
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Sinkholes

• Vegetation not found in surrounding xeric
  environments
• Often contain unique vegetation due to
  microclimate
• Needle palm is found almost exclusively in cool,
  moist sinks.
• Needle palm is a Pleistocene holdout

Needle Palm (Rhapidophylum hystrix)
Thalypteris spp. fern
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Sinkholes

• Not good for human- made objects
• Formation can be influenced by human activities,
  esp. well drilling
• Some appear to be just ponds

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Aquifers in Florida

• Floridan is main aquifer
• Biscayne in the south

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Spring Classification by Discharge (Size)

• First Magnitude (27 of them in Florida)
• 100 cubic feet/second or 65 Million Gallons/Day
  (mgd)
• Second Magnitude
• 10-100 cubic feet/second or 6.5-65 mgd
• Third Magnitude
• 1-10 cubic feet/second or 0.65-6.5 mgd
• Fourth Magnitude
• lt1cubic foot/second or lt.65 mgd

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Spring Classification by chemistry

• Measure specific conductance (total ion
  exchange)measures hardness
• Measure specific ions such as chlorides and
  sulfates
• Also can measure nitrogen and phosphorus
• usually low
• indicate water quality

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Organisms

• Phytoplanktonbase of food chain
• Plants (we will learn some of these)
• Floating
• Emersed--in water with roots or stems rooted in
  substrate
• Submersedentirely underwater (except maybe
  flowers and fruits)

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A short side show on invasive vs. exotic

• What is exotic (non-native)? Invasive? Theyre
  not the same!!
• We will cover this in detail next week

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Animals

• 126 spp. Of strictly freshwater
• Euryhaline fish
• Wide range of salinity depending on tidal flux
• St. Johns has 170 spp. Fish 115 are brackish
• S. Florida only 29 are strictly freshwater
• Tarpon in rivers in summer
• Red fish,sea trout, crevalle jack in fall in
  rivers
• Endangered/threatened, inc. Atlantic Sturgeon
• Exotics
• 31 spp. Including tilapia

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Another euryhaline fish includes the mullet

• Go way upstream as far as Silver Springs near
  Ocala
• Mullets live in families!
• Live in a variety of habitats but prefer the
  south (the hair, not the fish)
• Spawn in salt water, live most of their lives in
  freshwater (the fish, not the hair)
• Some mullets are prettier than others (both)
• Mullets should stay deep under water (both)

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Other important animals

• The beloved West Indian Manatee
• Lumps of grey fat
• The not so beloved molluscs
• Very high diversity, esp.
• snails and clams
• In decline
• Used as indicator species

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What are some impacts on springs you can think of?
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Effects of Pervious vs. Impervious Surfaces
10-20 impervious
Natural Ground Cover
Evapotranspiration 38
Evapotranspiration 40
Infiltration 50
Runoff 10
Runoff 20
Infiltration 42
35-50 impervious
75-100 impervious
Evapotrans. 35
30 evapotrans
Runoff 30
55 runoff
15 infiltration
Infiltration 35
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Where are they?

• Most in panhandle/C. Florida
• None in South Florida (S. of Lake Okeechobee)
• First Magnitude (gt100 cubic feet/second) shown
  here

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Florida Freshwater Use, 1995
Ground Water 4,336 mgd
Surface Water 2,881 mgd
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Some cool Florida spring websites

• http//www.thiswaytothe.net/springs/