Vocabulary:consumer, coral, coral bleaching, coral reef, filter feeder, food chain, food web,
grazer, nutrients, ocean acidification, pH, plankton, predator, producer, sediment, zooxanthellae
Prior Knowledge Questions (Do these BEFORE
using the Gizmo.)
1. Look at the graph to the right. What does it show?
It shows that the percentage of coral cover in the
Caribbean Reefs are slowly declining overtime.
2. Why do you think coralshave declined since 1977?
I think the main causes for the decline of corals over the years is due to overfishing and
global warming.
Gizmo Warm-up
Coral reefsare some of the most diverse habitats on
Earth, home to over a quarter of all marine species. The
Coral Reefs Gizmo provides a simplified model of
interactions among 10 key species in Caribbean reefs. In
the Coral Reefs 1 exploration, you will focus on the effects
of environmental factors on Caribbean reefs.
1. Click Advance year10 times. Look carefully at the composition of the reef over time. Do
you see any major changes?
No major changes, the reef stayed consistent.
2. Select the DATA tab. Check that Staghorn coral, Star coral, Sponges, and Algaeare
selected. Populations are given as a percentage of normal populations.
, What do you notice about these populations?
Sponge population rose, while other species had their populations remain the same.
3. On the right side of the Gizmo, select the SUMMARYtab. In a healthy reef, what are the
values for Nutrient load, Water clarity,Coral cover, and the total number of fish species?
Nutrient load: 4 ppt Water clarity: 94% Coral cover: 49% Total fish species: 442
Get the Gizmo ready:
Activity B:
● On the CONDITIONStab, Click R eturn to original
Ocean conditions settingsand Restart. Check that Ocean
conditionsis selected on the dropdown menu.
Introduction:In recent decades, global climate change has altered ocean conditions in the
Caribbean. Average surface temperatures have risen about 0.25 °C – 0.5 °C. Many scientists
think climate change will lead to stronger storms and may cause the ocean to be more acidic.
Question: How are coral reefs affected by storms, high temperatures, and acidic water?
1. Predict: Coral reefs in the Caribbean are sometimes damaged by hurricanes. Of the two
types of coral shown, which do you think is more resistant to storm damage? Explain.
The Boulder Coral because it’s thick shell will most likely allow it to better withstand a
large storm.
2. Observe: Set the Storm severityto 50%. Click Advance year 10 times. What changes do
you notice?
The Staghorn population decreased, algae starts to grow, urchins and coral start to
slowly die.
3. Analyze: On the DATA tab, select Staghorn coral, Star coral, Sponges, and Algae. Which
organism was most hurt by increased storms, and why do you think this is so?
Staghorn coral because it's the most delicate Caribbean coral.
4. Predict: In the Caribbean, water temperatures typically range from 24 °C to 30 °C. What do
you think might happen if temperatures rise much higher than 30 °C?
Many species that are currently living in the Caribbean might slowly die off and new life
forms will grow.
5. Observe: Select the CORAL REEFtab. Click R
eturn to original settingsand Restart
. Set
the Ocean temperatureto 33 °C. Click A
dvance year10 times.