Florida State University Libraries
Undergraduate Research
2015 Symposium
2015
Fluctuations and Trends in Chlorophyll-a in
the Arctic Ocean
Joshua Stacy
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Chorophyll a Trends and Variations in the Arctic Ocean
Joshua Stacy and Tachanat Bhatrasataponkul
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Department of Earth, Ocean and Atmospheric Sciences,
Florida State University, Tallahassee, FL, 32306
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Introduction
Primary productivity, or the rate at which
energy is converted to organic substances, can
be determined by analyzing trends in
chlorophyll-a in an ocean region over time.
Chlorophyll-a is a chemical produced by
photosynthetic organisms that is used to
convert light into chemicals which they can use
for energy. Therefore, primary productivity and
the amount of chlorophyll-a present in a region
have a direct correlation. The purpose of this
experiment was to determine how quickly the
primary productivity in the region is changing,
as any sort of rapid change could have any
number of unknown effects o the ecosystem.
Using NASA's Terra and Aqua satellite's
pictures, one can analyze fluctuations and
trends in chlorophyll a over time so as to see
how current circumstances, namely global
warming, have affected primary productivity in
the region. The Arctic Ocean in particular is of
note due to the increasing amount of freshwater
input which is mainly a product of global
warming causing increased ice melting and
runoff. The greater water clarity afforded by the
input of extra freshwater causes an overall
increase in primary production while still having
abnormally low primary productivity rates in the
winter due to sea ice covering much of the
ocean's surface
Results
Conclusion
Based on the data, chlorophyll a concentrations are
steadily rising over time in the Arctic Ocean. As the
amount of carbon found in the atmosphere increases over
time, higher temperatures cause greater volumes of
freshwater to be dumped into the Arctic Ocean. The result
is a greater number of photosynthetic organisms which
can be detected by their chlorophyll a using ocean color
remote sensing. Additionally, the two years where there is
observed the greatest spike in chlorophyll a, 2011 and
2014, are also the years which observed the lowest sea
ice extent covering the Arctic Ocean(Frey et al, 2014). Due
to Arctic amplification, this loss of sea ice only goes to
further
increase
average
temperatures
in
the
region(Serreze et al, 2009) causing greater freshwater
runoff and loss of sea ice cover.
References
Figure 1 graphs chlorophyll a concentrations from 2004 to 2014 showing spikes in chlorophyll a
concentrations in 2008, 2010 and 2014. Additionally, chlorophyll a concentrations tend to increase
the further into the summer it gets with May having the lowest average chlorophyll concentrations
and August having the highest average chlorophyll a concentrations.
Methods
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Using NASA's ocean color website which
uses photographs from it's Aqua and Terra
Satellites, pictures of average chlorophyll a
per month can be downloaded onto SeaDAS
software. Using SeaDAS, the Arctic Ocean
can be broken down into zones and the
software then interprets the different
wavelengths of color into concentrations of
chlorophyll a for each zone. These
concentrations are averaged together to find
a mean concentration per each month. This
method for finding average concentration is
then repeated multiple times until a cohesive
picture month-to-month of chlorophyll a
concentrations is established.
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OC Home Page | Ocean Color Web. (n.d.). Retrieved from
http://oceancolor.gsfc.nasa.gov/cms/homepage
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Lindsey, R. (n.d.). World of Change: Arctic Sea Ice. Retrieved from
http://earthobservatory.nasa.gov/Features/WorldOfChange/sea_ice.php
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Serreze, M., Barrett, A., Stroeve, J., Kindig, D., & Holland, M. (2009).
The emergence of surface-based Arctic amplification. Retrieved from
www.the-cryosphere.net
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Frey, K., Comisco, J., Cooper, L., Gradinger, R., Grebmeier, J., Saitoh,
S., & Tremblay, J. (2014, December 2). Arctic Ocean Primary
Productivity. Retrieved from
http://www.arctic.noaa.gov/reportcard/ocean_primary_productivity.html
Acknowledgements
I would like to thank the Ph.D. candidate in charge of my project,
Tachanat Bhatrasataponkul, for his help learning what software to use.
I would also like to thank Joe O'Shay and my UROP leaders
Marianella Pimienta and Lauren Luscuskie.
Figure 2 is a map of chlorophyll a world-wide(October, 2009) where the brighter/higher wavelength
colors represent areas of higher concentration and the darker/lower wavelength colors represent area
of lower concentration.