Download Ecosystems of Aquifers and Springs

I. Ecosystems
A. Most aquifers do not support traditional
aquatic ecosystems.
1. No light, no photosynthesis (for plants)
2. No nutrients
3. No dissolved O2 to support aerobic life.
4. Survivors include: bacteria, protozoans,
and other unicellular organisms.
B. Karst aquifers support a more complex
aquatic ecosystem in underground cave
habitats.
1. Invertebrates, fish and amphibians make up
the majority of the organisms.
2. Nutrients are recycled among the organisms
due to the lack of producers.
3. Have a very low carrying capacity.
4. Adaptations
a. Absence of eyes
b. Many devoid of
color
c. Increased sensory
development including, antennae,
chemoreceptors and touch receptors.
d. Consistent water temperature supports a
lower metabolism which means less food
require.
e. Environment stable
and predictable.
C. Nutrient Support from the outside
1. Cave-dwellers depend on the plant and
animal material washed into the caves.
2. Feces dropping from bats and mice provides
nutrients for fungal growth which many
insects eat.
4
3. Food chain:
Fungi insects insect larva
invertebrates
blind salamander
toothless blindcat
(catfish).
Death of
the catfish
would
provide
nutrients
and cycle
continues
5
D. Spring Ecosystems
1. Food provided by aquatic plants and algae
2. Isolated habitats of many springs contain
species found only in that particular location.
3. Consistent water temperatures near the springs
the cave openings prevent organisms from
wandering to the streams and rivers associated
with the spring.
6
4. Ecosystems are small providing limited
numbers of any one species population to
survive.
7
E. Changes Impact the Habitat
1. Decrease in ground water flow or drought
reduces habitat and stresses many species.
2. Invasive species enter native springs and take
over often eliminating the indigenous species
of the spring.
3. Human impact on springs vary; from building
dams across the springs
to building recreational
pools destroying the
native species.
8
II. Water Supply Problems for Aquifers and Springs
A. Water Supply Problems
1. Water Quantity
a. Spring runoff is highly dependent on
rainfall
b. Not enough recharge times between
drought
c. Edwards aquifer holds a huge amount of
water but: At less than 95% capacity,
the springs run dry.
d Wide spread fauna and flora inhabit
springs and caves and are vulnerable to
extinction if water levels get too low.
2. Water Quality a. Vulnerable because
aquifer is relatively
shallow
b. Little reaction time
in case of a spill
c. Clean-up of local threats almost impossible
Aquifer has a low self-cleaning ability
(natural remediation)
http://www.watersheds.org/earth/karstmovie.htm
11
3. Sources of Pollution –
a. Solid waste
1. Wild depositions in dolines (sink-holes) are
common in many area
2. Strong precautions for sealing dump-sites
b. Waste water
1. high risk from leaking sewers
2. used water infiltrates aquifer
3. no surface drainage system
c. Agricultural use
d. Industrial contamination
e. Hydrocarbons-explosive
f. Liquid waste injection
III. Environmental Impact
A. Eight species in the Edwards Aquifer, Comal Springs,
and San Marcos Springs ecosystems are currently
listed by the U.S. Department of Interior, Fish and
Wildlife Service, as either threatened or
endangered species.
Endangered
Comal Springs Dryopid Beetle
Comal Springs Riffle Beetle
Fountain Darter
Peck’s Cave Amphipod
San Marcos Gambusia
Texas Blind Salamander
Texas wild-rice
Threatened
San Marcos Salamander
14