CHAPTER 7MARCH 26T H , 2015

Terrestrial Caves Solution Holes and

Sinkholes

Terrestrial Caves and Sinkholes

Limestone still dominatesOccur all over Florida

1) Terrestrial Caves2) Sink Communities

Terrestrial Caves

Air filled spacesForm below the water table as water-filled

spaces. As groundwater levels drop (usually because sea level

drops), they fill with air. If cave’s roof strong enough, can hold up

overlying earth for centuries, a dry cave. If caves in, forms a sink.

Sink, or sinkhole = a circular depression on the land surface caused by dissolution of underlying limestone

More on SINKS later…

Terrestrial Caves

100’s of caves and tunnels in FL’s limestonePredominantly in Woodville, Marianna, and

Ocala Karst Plains: Many just West of TLHVary in size, tiny pockets, to room, to concert

halls100 years of dissolution = 1 in3 of cavern

formation

Caves

Outside/Entrance Entrance covered in plants usually Many animals found around and deep in caves.

Inside Humid atmosphere Constant 65-70 deg. F Little to No Light

Life in a Cave

No light-No photosynthesis, no plants except entranceFOOD WEB:Most nutrients brought in from outside the

caves Surface water runoff, plant litter washed in Forage outside of cave, bring inside Bats, woodrats can come and go

Inside Predators prey on other cave inhabitants Droppings, bat guano! Carcasses Decomposers: Fungi and Bacteria

Inside: Darkness

Stable environment, constant temp. Trade off of stability is darknessAdaptations:

Loss of eyesight Loss of pigmentation Enhanced Chemo sensors:

Enhanced smell and taste

Adaptive because: Energy not consumed to develop unnecessary pigment

or sight

Genetic Isolation: Unique Species Evolve

MillipedesSpidersMitesCrayfishBATS! ArthropodsSalamanders

Specialized animals

Rely on other senses Long limbs for probing in dark Chemical sensors-finely tuned Motion detecting organs Colorless & blind

Genes lots—invest resources for reproduction

Florida Bats: Misunderstood

12 species still exist in FL

3 cave roosters Gray Bat Southeastern Bat Eastern Pipistrelle

Not blind, rely on Hearing/Echolocation

Do not attack humansRarely carry rabiesMammals2 offspring a yearWeigh > 1 ouncePollinators, seed dispersersAlso insect eaters

500 insects per hour! Equal to their body weight

each night Effective as insectiside

except non-toxic!

Florida Bats

Sinkhole

A circular depression on the land surface caused by the dissolution of underlying limestone

4 types: Wet sink Dry Sink Solution Hole Funnel Sink

Water table =the level at which groundwater rests

Types of Sinkholes1. Wet Sink

Deep conical hole in ground that intersects the water table

Water at bottom = Aquifer water“Window into Aquifer”Collapsed limestone fell into the groundwater

Types of Sinkholes2. Dry Sink

A shallower conical hole in ground that is dry all the way to bottom

Collapsed limestone remained ABOVE groundwater

Types of Sinkholes3. Solution Hole

A water holding hole in the surface limestone that does not intersect with water table

Can usually tell difference between Wet sink and solution hole by color of water Blue = Wet sink, Aquifer water Green = Solution hole,

rainwater

Water at bottom = rainwater Bottom may have been open

at one point, now “plugged”

Types of Sinkholes4. Funnel Sink

A sinkhole with water swirling down to a lowered water table.

When water table rises, the funnel sink becomes a spring, propelling water upward with force.

Ex: Leon Sinks field trip “Disappearing stream”