N.S.T.A. Science Objects 3 of 4
The Coral Reef Ecosystem: Interdependence
*Ecology-the study of the interaction of living things with each other and their
environment
*Plankton: 1) Zooplankton (animal plankton) and 2) Phytoplankton (smaller
chlorophyll bearing plankton often called “grasses of the sea)
*Food Chains
Producer (Make food from the sun’s energy…photosynthesis)
Primary Consumer
Secondary Consumer
Tertiary Consumer
*All food chains have a producer and at least one consumer
*Last predator in a food chain in called the apex predator
*Food chains are linked to each other through food webs
*Trophic level of the food pyramid
*lowest concentration of energy is at the top trophic level
*Recycling on the Reef
*Water cycle
*”Food cycle”
*Carbon dioxide-oxygen cycle
*Symbiosis on the reef
Symbiosis
Mutualism (both organisms benefit)
(i.e. polyps and zooxanthellae
Clownfish and anemone)
Commensalism
(one partner benefits and
the other remains
unaffected)
(i.e. reef shark and
remora)
Parasitism (one partner benefits and the other is harmed)
(i.e. reef fish and worms)
4 of 4
Coral Reef Ecosystems: Ecosystems in Crisis
*Natural events that destroy the coral reef ecosystem:
A. Stormy weather (i.e. hurricanes, typhoons) can destroy coral reefs
B. Tsunamis (caused by underwater earthquakes)
1. Less damage is done to healthy coral that has not been
Affected by human activity
C. Reef raiders
1. Crown of thorns seastar (strips coral of all soft tissue)
a. It’s abundance is caused from the shell collectors
who collect the Great Triton (it’s main predator) thus
causes the C-of-T population to increase
D. Disease
1. May be caused by ocean acidification or rising water temps
*Human Events that destroy the coral reef ecosystem
A. Bleaching-when the polyps expel the zooxanthellae
1. Due to increase of water temperature (even 1 degree Celsius), can
also be from sewage in the water, cloudy water, low O2 levels, and
Other toxic material in the water
2. Coral can fix itself but become more susceptible to disease and
If they die it disrupts the ecosystem
B. Ocean Acidification-when CO2 in the atmosphere is absorbed into the
ocean
1. Lowers the pH of the water and the concentration ion of carbonate
Decreases and makes it harder for coral to form.
2. The acidity can also dissolve coral
C. Runoff-toxicants and sediment in storm water runoff
1. The cloudiness in the water prevents photosynthesis
2. Overgrazing and clear cutting causes more erosion of the land and
Overpopulation (more petroleum based toxicants in runoff)
3. Water from sewage plants and agriculture may stimulate algal
growth
a. Algal blooms cover sunlight and prevent photosynthesis in
coral polyps
b. Algal blooms also cause other algae to die to lack of sunlight
and this dissolves O2 levels
4. Chemical Fertilizers
D. Commercial Exploitation
1. Overfishing/damaging fishing techniques
a. Sea cucumber delicacy (endangered now)
b. Unbalanced predator/prey relationships
c. Dynamite fishing and poison fishing cause excessive damage
E. Invasive Species (non-native species that disrupts the balance of an
ecosystem)
1. Mainly from ballast water discharge (water let off of ships when
They dock…release non-native larvae, eggs, microscopic organisms
F. Ship Groundings
G. Tourism and Recreation
1. People who run their boats into shallow corals
2. People who stand on, touch, and/or remove coral
3. Fishing gear damage and anchor damage
H. Marine Debris
1. U.S. has 10 million tons of trash that is dumped into the ocean
2. Suffocation or starvation from ingesting plastic bags
3. Choking and suffocating on plastics
4. Plastic bags can suffocate a coral reef
5. Oil spills and toxic spills damage coral reef ecosystems, too
*Endangered Species
A. The U.S. made it illegal to kills, hunt, injure, or harass marine mammals
In 1972
B. Levels of threats: Endangered, Threatened, Species of Concern