Investigations Using a Digital Camera To Quantify
Color Changes in Aiptasia pallida Due to Two
Environmental Stressors: Heat and Light
Presented by
Jennifer Welborn
June, 20111
Overview
•Background– Aiptasia as a model organism
•Procedure for Temperature Experiment
• Procedure for Light Experiment
•Sample ADI procedure– Rectangle Tool
•Sample ADI histogram
•Helpful Hints
Aiptasia as a Model Organism for The Effect of Global
Environmental Change on Corals
Background
• Coral bleaching--serious consequence of global environmental change.
• Corals have a symbiotic relationship with
algae
* algae provide food
* anemone provides shelter
• Coral bleaching– corals are stressed by
environmental factors, release algae, turn white and die
• Environmental stress factors
• increased water temperatures (global warming)
• lower pH (ocean acidification)
• increased water turbitity (pollution effects)
Background Continued
• Aiptasia pallida -- small anemones similar enough to coral to be used as a
model organism in labs.
• Unlike corals, Aiptasia are hearty and will not die if stressed to the point of
releasing their symbiotic algae. They are able to get food by stinging
and eating small organisms living in the water.
• Aiptasia -- can be used for coral bleaching research without harming them.
Aiptasia pallida
The “bleached”
Aiptasia on the
right have
released their
algae due to
environmental
stress
Experiment 1: The Effect of Increased Temperature on the Color of
Aiptasia Over Time
Research Questions
• What is the effect of increasing water temperature on Aiptasia pallida?
• Can we quantify a change in color that is related to the stress on an
organism using a digital camera?
Procedure
1. 5 groups of 3 STEMDIGITAL participants set up the lab according to the
pupil page directions for temperature.
2. Wait a few hours for the anemones to get acclimated.
3. Create initial photographs according to the Using Your Digital Camera
as a Data Collection Tool directions given in the pupil page handout.
4. Use the polygon or rectangle tool for the ADI analysis. Record R, G, B
values. Create a histogram of the data.
5. Photograph the four anemones each day. Compare R, G, B values and
histograms to see constancy or change over time.
6. Compare data with other groups doing the same experiment.
Experiment 2: The Effect of Decreased Light on the Color of Aiptasia
Over Time
Research Questions
• What is the effect of decreasing light on Aiptasia pallida?
• Can we quantify a change in color that is related to the stress on an
organism using a digital camera?
Procedure
1. 5 groups of 3 STEMDIGITAL participants set up the lab according to the
pupil page directions for light.
2. Wait a few hours for the anemones to get acclimated.
3. Create initial photographs.
4. Use the polygon or rectangle tool for the ADI analysis. Record R, G, B
values. Create a histogram of the data.
5. Photograph the four anemones each day.
6. Compare R, G, B values and histograms to see constancy or change
over time.
7. Compare data with other groups doing the same experiment.
Sample Spatial Analysis Using Rectangle Tool
Sample Histogram From
Spatial Analysis Data
Helpful Hints
1. Trace the bottom of an empty petri dish on black
paper for consistent placement of experimental
dishes when capturing images
2. Use a tripod/ring stand for consistency.
3. Keep camera parallel to dish to avoid parallax.
4. Remove lid from dish when photographing to
avoid reflection.
5. Make sure there is label in each photo with date
and time.
6. Make sure the bottom of each dish has been
labeled for identification in each photo.
7. Aim for consistency of ambient light.