Comparing Sea Surface Temperature and Chlorophyll
Concentrations
Modified loosely from the Science Education Resource Center at Carleton College at:
http://serc.carleton.edu/eslabs/fisheries/7_b.html
Time Frame:
Subject(s):
Grade Level:
90 minutes
Environmental Science- Human Interactions, Weather and Climate
Oceanography- Ocean Ecology
6-12
Overview
The purpose of this activity is to help students interpret the various colors in satellite images, some of the most
common and useful types of data used in marine science research. The colors will be analyzed to understand
the relationship between phytoplankton and chlorophyll concentration and also the relationship between
chlorophyll concentrations, temperature and land use. Access to a suite of current satellite data can be found at
NASA’s Giovanni website: http://disc.sci.gsfc.nasa.gov/giovanni
Vocabulary
Phytoplankton, sea surface temperature, chlorophyll, photosynthesis, algal blooms
Standards
Next Generation Science Standards
HS-ESS3-5.
Analyze geoscience data and the results from global climate models to make an evidencebased forecast of the current rate of global or regional climate change and associated future
impacts to Earth systems.
HS-LS2-6.
Evaluate the claims, evidence, and reasoning that the complex interactions in ecosystems
maintain relatively consistent numbers and types of organisms in stable conditions, but
changing conditions may result in a new ecosystem.
Common Core State Standards
RST.11-12.8.
Evaluate the hypotheses, data, analysis, and conclusions in a science or technical
text, verifying the data when possible and corroborating or challenging conclusions
with other sources of information.
WHST.9-12.2.
Write informative/explanatory texts, including the narration of historical events,
scientific procedures/ experiments, or technical processes.
WHST.9-12.7.
Conduct short as well as more sustained research projects to answer a question
(including a self-generated question) or solve a problem; narrow or broaden the
inquiry when appropriate; synthesize multiple sources on the subject, demonstrating
understanding of the subject under investigation.
Environmental Science Standards
SEV3.
Students will describe stability and change in ecosystems.
a. Describe interconnections between abiotic and biotic factors, including normal
cyclic fluctuations and changes associated with climatic change (i.e. ice ages).
Oceanography Standards
SO3.
Students will analyze how weather and climate are influenced by the oceans.
a. Identify general global patterns of atmospheric and oceanic circulation including
variations such as El Nino and monsoons.
b. Explain the influence of the Coriolis Effect on winds, ocean currents, and on
weather and climate.
c. Describe the effects of tilt of the earth, solar energy inputs, and heat capacity of
land and oceans on the resulting patterns of weather and climate.
Student Activity
Comparing Sea Surface Temperature and Chlorophyll
Concentrations
These exercise is divided into Parts A and B
Materials - for both parts
Satellite images of chlorophyll concentrations and sea surface temperature
 Chlorophyll Concentration
o http://neo.sci.gsfc.nasa.gov/view.php?datasetId=MY1DMM_CHLORA
 Sea Surface Temperature (SST)
o http://neo.sci.gsfc.nasa.gov/view.php?datasetId=MYD28M
 Giovanni Ocean Color Radiometry Online Visualization and Analysis, Global Monthly Products
o http://gdata1.sci.gsfc.nasa.gov/daac-bin/G3/gui.cgi?instance_id=ocean_month
Part A
Background
Phytoplankton (planktonic photosynthetic microbes) in the oceans produce an estimated 50-85% of the
oxygen on earth. Phytoplankton productivity (formation of new organic carbon from carbon dioxide) through
photosynthesis can vary significantly between ocean regions and over temporal scales. What are some of the
factors that regulate this productivity? How can we monitor global productivity patterns? Chlorophyll in the
water affects the way water reflects and absorbs sunlight, allowing maps of chlorophyll concentration to be
created from satellite images of ocean irradiance (emitted wavelengths of light), or color. We can use these
images to examine global patterns in chlorophyll concentration. Such patterns tell us about the distribution of
primary producers. The use of satellite imagery has transformed ocean science over the past 50 years,
allowing detailed mapping of marine organisms and processes at varying scales, from meters to the scale of
entire oceans, and therefore allowing us to draw conclusions about the cycling of carbon and other important
elements in marine food webs. Here, we will use publically available satellite data to examine global and
regional patterns in chlorophyll concentrations. These patterns will challenge students to consider the factors
(physical, chemical, biological) that influence the distribution of primary production in the ocean, as well as the
importance of characterizing this distribution.
Activity
1. Navigate to the following websites:
a. For chlorophyll: http://neo.sci.gsfc.nasa.gov/view.php?datasetId=MY1DMM_CHLORA
b. For sea surface temperature: http://neo.sci.gsfc.nasa.gov/view.php?datasetId=MYD28M
2. After familiarizing yourself with the website, examine images of both sea surface temperature and
chlorophyll monthly averages from January, April, July, and October of the previous year. Answer the
questions below after viewing the above images.
a. Is there a clear relationship between sea surface temperature and chlorophyll?
b. How does this pattern vary across seasons?
c. What factors might explain the relationship between these two variables?
Expected Outcomes
Students should see that regardless of season, phytoplankton abundance is greatest in cold water regions or in
places where ocean currents bring cold water to the surface, such as around the equator and along the shores
of continents. Also, in polar waters, nutrients accumulate in surface waters during the dark winter months when
phytoplankton can’t grow. When sunlight returns in the spring and summer, the plants flourish in high
concentrations. In the next section, we will examine some of the factors that drive the patterns we have seen in
part A.
Part B
Background
Harmful algal blooms (HABs) can arise when excess nutrients reach oceans, often through anthropogenic input
(caused or produced by humans). Many phytoplankton species that contribute to HABs produce toxins that can
kill or poison fish and other marine organisms, as well as humans that may consume these organisms. In this
part of the investigation, we will use images and data from the MODIS (Moderate Resolution Imaging
Spectroradiometer) instrument aboard the Terra satellite to look for correlations between phytoplankton density
in the Gulf of Mexico and the addition of nutrients through agricultural runoff from the surrounding land. This
will challenge students to think about how knowledge of phytoplankton distributions has relevance to questions
of human and marine ecosystem health.
Activity
1. Go to the Giovanni Ocean Color Radiometry Online Visualization and Analysis website:
http://gdata1.sci.gsfc.nasa.gov/daac-bin/G3/gui.cgi?instance_id=ocean_month
2. Select the area surrounding the Gulf of Mexico by clicking and dragging a box around it on the world
map.
3. Under the MODIS-Aqua 9km satellite, select “Chlorophyll a concentration” as the parameter.
4. Scroll to the bottom of the screen. Under the Temporal tab, select a Begin date of January 2012 and an
end date of December 2013.
5. Under the Select Visualization tab, make sure “Animation” is selected.
6. Click Generate visualization (it may take a couple of minutes for the data to process and appear).
7. You can play the animation completely through the time series by clicking the play button, or you can
use the step forward button to advance the animation one month at a time.
8. Describe the variation in the chlorophyll levels in the Gulf of Mexico during the two year period covered
by the animation. Are there certain times of year during which chlorophyll levels are particularly high or
low? Explain why you think these differences exist. In general, in what area(s) of the Gulf are
chlorophyll levels highest? Explain why you think this occurs.
9. Repeat the analysis for a different ocean region. Are the patterns the same?
Expected Outcomes
Students should understand that land use patterns and runoff lead to algal blooms in coastal systems (they will
be specifically examining the Gulf of Mexico as a case study). They should also be able to describe seasonal
patterns in algal bloom formation.
Discussion questions
1.
2.
3.
4.
5.
How do satellites measure chlorophyll concentration?
Why are such measurements useful?
What can we learn about marine ecosystems by mapping chlorophyll concentrations?
What factors affect the distributions of primary producers, and therefore chlorophyll?
How would you expect concentrations to vary over space and time? In what types of ocean habitats
are concentrations highest and lowest? Why?
6. What other properties of marine ecosystems can be monitored by satellites?
7. What can we learn from those properties?
Extension
1. Teachers could have the students focus on temperature/chlorophyll relationships in a particular
upwelling region or local current.
2. Ocean color technologies are also useful in monitoring toxic and harmful algal blooms. Have students
take a look at NOAA’s Phytoplankton Monitoring Network and Bigelow Laboratory’s Algal Blooms
websites. What are the causes and effects of harmful algal blooms? How can ocean color technology
help us track and control these effects?
Teaching Notes and Tips
It is important that images be printed in color (or laminated for extended class use) if the activity is not done on
the computer. Discuss with students the importance of satellite information and how it can aid scientists in
determining various patterns throughout the ocean and make predictions about plant and animal life. Help
students become familiar with the term sea surface temperature and chlorophyll concentrations. Help students
realize the difference in concentrations during the various seasons throughout the year and why might that be
the case? This assignment may best be done in pairs where students can interact and ask questions of one
another to gain clarity.
References
Emery, W. J. "Sea Surface Temperature." Elsevier Science (2003): 101-09. Web.
Rachel, Collin, Luis D'Croz, Plinio Gondola, and Juan Del Rosario. "Climate and Hydrological Factors Affecting
Variation in Chlorophyll Concentration and Water Clarity in the Bahia Almirante, Panama." Smithsonian
Contributions to the Marine Sciences 38 (2009): 323-334. Print.
"Rising sea surface temperature: towards ice-free Arctic summers and a changing marine food chain —
."European Environment Agency's home page — . N.p., 13 Apr. 2011. Web. 26 June 2013.
<http://www.eea.europa.eu/themes/coast_sea/sea-surface-temperature>.
Rachel, Collin, Luis D'Croz, Plinio Gondola, and Juan Del Rosario. "Climate and Hydrological Factors Affecting
Variation in Chlorophyll Concentration and Water Clarity in the Bahia Almirante, Panama." Smithsonian
Contributions to the Marine Sciences 38 (2009): 323-334. Print.
"Sea Surface Temperature." EPA. Environmental Protection Agency, n.d. Web. 26 June 2013.
"Sea Temperature Rise -- National Geographic." The Ocean -- National Geographic. N.p., n.d.
2013. <http://ocean.nationalgeographic.com/ocean/critical-issues-sea-temperature-rise/>.
Web. 26 June
Stewart, Robert . "Distribution of Plankton." Welcome to OceanWorld - Bringing the Ocean to the Classroom.
Department of Oceanography, Texas A&M University, n.d. Web. 27 June 2013.
<http://oceanworld.tamu.edu/resources/oceanography-book/phytoplanktondistribution.htm>.