Coral Connectivity in a Changing Ocean
Day _______________________________________
Learning Objective(s):
AZ DOE---Grade 6, Strand 4, Life Science, Concept 3: Populations of Organisms in an
Ecosystem (analyze the relationships among various organisms and their environment)
PO2: Describe how the following environmental conditions affect the quality of life:
• water quality
• climate
AZ DOE---Grade 7, Strand 4, Life Science, Concept 3: Populations of Organisms in an
Ecosystem (analyze the relationships among various organisms and their environment)
PO 5. PO5: Predict how environmental factors (e.g., floods, droughts, temperature changes) affect survival
rates in living organisms.
AZ DOE---Grade 8, Strand 4, Life Science, Concept 4: Diversity, Adaptation, and Behavior
(identify structural and behavioral adaptations)
PO6: Describe the following factors that allow for the survival of living organisms:
• seed dispersal
Objective: Understand the influence of ocean water quality on the connectivity of coral reef populations.
Sub-objective: Understand how stress decreases performance
Sub-objective: Understand how water quality influences coral larvae & coral recruitment
Sub-objective: Understand how stressed coral larvae influence coral connectivity
Sub-objective: Incorporate coral connectivity into management practices
Materials:
Touch Tanks (provided by Arizona Sea Life Aquarium)
Artemia cultures
-Artemia
-5-7 beakers
-hot plate or small heaters
-(acid/buffering solution)
Coral Reef Substrate (one for each lab group)
Bag of Lentils
Map of Marine Protected Areas (one per student)
During
Snack
Video of coral spawning
Video of on how climate influences water quality
*(make sure to get pre-approval so school firewalls don't interfere)
Engage
15 minutes
Marine Creature Observation
-Touch tank with sea urchins and other marine creatures
-Coordinated with Arizona Sea Life Aquarium
Reef Observation and Question Raising
-Students are shown videos/images of contrasting coral reefs with high coral cover
(healthy) and high algal/cyanobacteria cover (unhealthy/degraded) and asked to describe
the differences in what they see
--Play without sound: http://www.youtube.com/watch?v=DJK4X9jo9-0
-Students also write down what they think causes this difference
-Ask students how the marine creatures from the touch tank may influence and be
influenced “healthy” and “unhealthy” reefs
-Finally, students are asked to write down what they think can be done to keep the
healthy reef healthy
Explore
Activity to observe coral larvae response to different environmental conditions
-Students are given the details of the different preparations in the Coral Larvae Procedure
and asked to record their quantitative and qualitative observations.
-As the students cycle through the stations they should notice how increasing the
temperature/acidity (and the combination of both) decreases activity.
15 minutes -Record the results for each group in the class
Activity to observe the influence of amount of larvae on coral recruitment success
- Students play “Probability of Coral Recruitment” exercise
- For each treatment the students record their quantitative observations
- At the end of the exercise the students are asked to make qualitative observations
- Record the results for each group in the class
Explain
10 minutes
Students are formally introduced/reintroduced to the relationship between stress and
performance, environmental condition (water quality) and larval stress, and encouraged to
explain how these variables contribute to larval recruitment this will what contributes to
larval recruitment
-Students are asked to put their observations of “coral larvae” into the context of
physiological stress (“Why did temperature/acidity cause the individuals to take more/less
time to travel the same distance?” “What happened when stresses, increased temperature
and acidity were combined?”)
-Definitions are supplied for all concepts in the “terms list”
-Students should be asked many questions to facilitate the discussion. Also, use this time
to clarify why you did or did not find differences between the environmental stations and
make connections to the community dynamics and probability
Expand
15 minutes
Students are given a fake map of an ocean body with 12 potential marine protected
reserves
-each area is described simply
--relative coverages of coral vs. algae vs. free space is given
--sea surface temperatures
--acidity is assumed to be constant, but increased over current levels (note pH is lower
near the equator)
--(Distance is implied by the map itself)
-Students are then asked to identify areas of high conservation value (good areas to put a
marine protected reserve), 7 of locations will be appropriate, some potential reserves are
in poor condition and should be triaged, and the remaining should be picked to create
“even” spacing of reserves.
-The instructor gives an example of the appropriate reserves to select and corrects
misconceptions with poor reserve choices.
Evaluate
5 minutes
In conclusion, each student is told they have just been hired by the United States
government to determine what environmental characteristics to consider to help manage
a system of marine reserves. They should right down 2-3 sentences for each characteristic
and explain why it is important. Then they should also write down what can be done to
maintain healthy reefs and what can be done to improve the quality of degraded reefs.
(Looking for Temperature, Acidity, and Distance, but if they picked up additional
considerations they are free to address them as well!)
“Coral Larvae” (Artemia*) Procedure
1. Prepare culture of artemia 24 hours in advance
2. In classroom separate culture into 5-7 beakers (1 for each station)
a. 2-3 beakers will be for temperature (Room and 1 or 2 above room temp)
b. 2-3 beakers for increased acidity (High, low, and possibly an intermediate)
c. 1 beaker for the highest temp combined with the lowest pH
3. Place beakers on hot plates as appropriate
*Although juvenile brine shrimp swim differently than coral planulae, they are relatively the same size and
assumed to serve as an appropriate proxy
At each station students:
1. Time how long it takes a single artemia to circle the beaker
2. Repeat and observe 3 different “Coral Larvae”
3. Record quantitative results (time) for all observations
4. Make qualitative observations (type movements) during this investigation. Record these results
Lastly, record the results for each group in the class.
DATA TABLE:
Station
Treatment
1
Room Temp
2
High Temp
3
Normal
Acidity
4
High Acidity
5
High Temp &
High Acidity
Larvae 1 Time
Larvae 2 Time
Larvae 3 Time
Average
Larvae Time
Probability of Coral Recruitment
Coral larvae floating on currents eventually settle in empty spaces form new colonies
1. Each lab group is given the “Coral Reef Substrate” handout and a reservoir of coral larvae (dry lentils)
*the handout has a barrier to prevent larvae from leaving the reef
2. Students are asked to randomly add beans to the paper (by dropping or throwing)
a. First treatment: 5 beans
b. Second treatment: 20 beans
c. Third treatment: 100 beans
3. Number of beans landing on “free space” are recorded
4. Then qualitative observations are recorded on how larvae densities influenced the chance of landing on
suitable habitat
Lastly, record the results for each group in the class.
DATA TABLE:
Trial
Number of
Larvae
1
5
2
20
3
100
Number Successful
Larvae
Percent Successful
Larvae
Percent Unsuccessful
Larvae
Terms and Definitions:
Biogeographic: Refers to the distribution of biodiversity over space. A biogeographic region is a
geographic area with similar dominant plants, organisms and prevailing climate conditions.
Calcium Carbonate: The mineral laid down by a coral to create the hard structure surrounding the
organism.
Connectivity: Describes the extent to which populations in different parts of a species’ range are linked
by the exchange of eggs, larval recruits or other propagules, juveniles, or adults; as well as the ecological
linkages associate with adjacent and distant habitats.
Cooling: Oceanographic conditions that cause mixing of heated surface waters with cooler deeper water
that can reduce temperature stress.
Coral Recruitment: Settlement of a coral larvae to a permanent location
Coral Bleaching: The process by which the symbiotic algae in a coral leaves its host, resulting in a loss of
color
Degree Heating Weeks: A combination of temperature anomalies and duration of exposure to quantify
the accumulated thermal stress in a particular region. One degree heating week is equivalent to one week
of sea surface temperature one degree Celsius warmer than the expected summer-time maximum.
Demographic Connectivity: Connectivity is much more than the biophysical coupling of larvae from
reproductive populations to recruitment sites. To sustain and grow, populations require an unbroken
nexus among reproductive populations called “demographic connectivity” (Steneck et al. 2009).
Ecosystem Resilience: The ability of an ecosystem to maintain key functions and processes in the face of
stresses or pressures by either resisting or adapting to change.
Fecundity: Refers to the potential reproductive capacity of an organism
Larval Duration: Pelagic larval duration refers to the amount of time the larvae spend in the open ocean
before settlement on the reef.
Marine Protected Area (MPA): Any area of intertidal or subtidal terrain, together with its overlying water
and associated flora, fauna, historical and cultural features, which has been reserved by law or other
effective means to protect part or all of the enclosed environment (IUCN definition).
Ocean Acidification: The declining pH (increased acidification) of the oceans due to increased
CO2 emissions globally.
pH: A measure of the acidity or basicity of a solution. pH provides an approximation of the concentration
of dissolved hydrogen ions (H+)
Recovery: The term recovery implies that a system will return to a previous condition after being in a
degraded or disrupted condition, one which is often interpreted as being in poor ecological health.
Recovery may occur naturally but can be accelerated by human intervention, implying that recovery will
occur in the system once the stressor is removed; it can be encouraged by or is the response to
management actions. If recovery is truly successful, then the community established will be similar in
species composition, population density and size and biomass structure to that previously present or
present at a comparable site.
Refugia: Secure areas that are protected by natural factors and/or human intervention from a variety of
stresses. They are meant to function as reliable sources of seed over time.
Replication: The process by which multiple samples of any habitat types are secured in a network of
protected areas. Replication helps to spread the risk of any large-scale event destroying all protected
examples of any habitat type.
Representation: The inclusion of a full range of habitat types into a protected area system.
Representation of all habitat types helps to ensure that the full complement of species for that habitat
type is protected.
Resistance: The capacity of an organism or a tissue to withstand the effects of a harmful environmental
agent. Resistance to bleaching is exhibited when coral colonies do not bleach, or bleach but don’t die. This
may vary among different parts of a reef and between different reef communities.
Salinity: Measure of salt per unit of water usually measured in parts per thousand (seawater is generally
around 35 parts per thousand).
Site Conservation Planning: Planning methodology which places sites in their larger ecological context;
setting conservation priorities and strategies to conserve both single and multiple conservation areas,
taking direct conservation action; and measuring conservation success.
Zooxanthellae: Symbiotic algae (in the dinoflagellate genus Symbiodinium) that lives in the tissues of
coral polyps and other host animals. The tiny photosynthetic organisms provide both nutrients and oxygen
to the corals and other host animals in which they live.
Reference
"Glossary." Reef Resilience. 2007. Web. 14 Dec. 2012.
http://www.reefresilience.org/Toolkit_Coral/C9a_Glossary.html
Background Information
Coral reefs begin to form when free-swimming coral larvae attach to submerged rocks or other hard
surfaces along the edges of islands or continents.
In addition to being some of the most beautiful and biologically diverse habitats in the ocean, barrier reefs
and atolls also are some of the oldest. With growth rates of 0.3 to 2 centimeters per year for massive
corals, and up to 10 centimeters per year for branching corals, it can take up to 10,000 years for a coral
reef to form from a group of larvae. Depending on their size, barrier reefs and atolls can take from
100,000 to 30,000,000 years to fully form.
Bottom topography, depth, wave and current strength, light, temperature, and suspended sediments all
act to create characteristic horizontal and vertical zones of corals, algae and other species.
Reef-building corals are restricted in their geographic distribution by their physiology. For instance, reefbuilding corals cannot tolerate water temperatures below 18° Celsius (C). Many grow optimally in water
temperatures between 23° and 29° C, but some can tolerate temperatures as high as 40° C for short
periods. Most also require very saline (salty) water ranging from 32 to 42 parts per thousand, which must
also be clear so that a maximum amount of light penetrates it. The corals’ requirement for high light also
explains why most reef-building species are restricted to the euphotic zone, the region in the ocean where
light penetrates to a depth of approximately 70 meters.
Corals can reproduce asexually and sexually. In asexual reproduction, new clonal polyps bud off from
parent polyps to expand or begin new colonies. This occurs when the parent polyp reaches a certain size
and divides. This process continues throughout the animal’s life.
About three-quarters of all stony corals produce male and/or female gametes. Most of these species are
broadcast spawners, releasing massive numbers of eggs and sperm into the water to distribute their
offspring over a broad geographic area. The eggs and sperm join to form free-floating, or planktonic,
larvae called planulae. Large numbers of planulae are produced to compensate for the many hazards, such
as predators, that they encounter as they are carried by water currents. The time between planulae
formation and settlement is a period of exceptionally high mortality among corals.
Along many reefs, spawning occurs as a mass synchronized event, when all the coral species in an area
release their eggs and sperm at about the same time. The timing of a broadcast spawning event is very
important because males and female corals cannot move into reproductive contact with each other.
Because colonies may be separated by wide distances, this release must be both precisely and broadly
timed, and usually occurs in response to multiple environmental cues.
Planulae swim upward toward the light (exhibiting positive phototaxis), entering the surface waters and
being transported by the current. After floating at the surface, the planulae swim back down to the
bottom, where, if conditions are favorable, they will settle. Once the planulae settle, they metamorphose
into polyps and form colonies that increase in size. In most species, the larvae settle within two days,
although some will swim for up to three weeks, and in one known instance, two months.
Reference
"Corals." NOAA's National Ocean Service Education. 18 July 2012. Web. 25 Nov. 2012.
http://oceanservice.noaa.gov/education/tutorial_corals/welcome.html
Potential MPAs Fact Sheet
Coral Cover (%) Algal Cover (%) Free Space (%)
Australia
43
34
23
Cook Islands
20
61
19
Fiji
45
51
4
Guam
26
70
4
Hawaii
22
22
56
New Caledonia
28
41
31
Palau
17
23
60
Samoa
43
50
7
Solomon Islands
30
45
25
Tahiti
27
29
44
Tokelau
8
85
7
Tuvalu
65
30
5
*Data presented are not factual
Temp. (°F)
87
78
83
80
75
80
87
85
88
77
83
84