Influences of Changes in Salinity on Release of Carbon by Phytoplankton
Jessica Wagner
Century High School
OGI & OHSU
Lab, Field, and Modeling Study
Mentors:
Tawnya Peterson
Joe Needoba
Karen Watanabe
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CMOP
• Field work• Modeling • In Situ Data• Lab Experiments
Center for Coastal Margin Observation & Prediction
Project Relevance
Water Samples, Carbon Model, Salinity Experiments
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Focus/Question
•Where fresh water meets salt water•Has many changes in salinity over short periods of time•Important for fish-creates a habitat•Biologically very productive
Question: How does the change in salinity affect the growth rate of freshwater Diatoms?
Estuary
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CDOM Cast Data
0
5
10
15
20
0 500 1000 1500 2000 2500 3000
CDOM-RFU (Cast 151)
De
pth
(m
)
CDOM Colored dissolved
organic matter http://www.gcrio.org
5Surirella sella
• Under salinity stress diatoms produce a larger amount of CDOM
• Eventually osmosis will cause the cell to shrink/burst
Observations
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Analysis of Variants (ANOVA)
x 10-3
5 10 15 20 25 30 35 40 45 502
4
6
8
10
12
14
Slo
pes
Growth Rate vs.
Salinity
Salinity (PSU)
Conclusion: Growth rates are
significantly different on the salinity range
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Salinity affects growth
What does this mean for the estuary and carbon cycling?
Salinity experiments that can show effect of changes in salinity on carbohydrates are needed
How do changes in salinity affect dissolved carbon release by phytoplankton?
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Salinity Experiment -May
FW-Control½ filtered fw½ none filtered fwSW-Shock½ Filtered sw½ none filtered fw
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Salinity Experiment-July
FW-Control½ filtered fw½ none filtered fwSW-Shock½ Filtered sw½ none filtered fw
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Summary
• Salinity affects growth of diatom • CDOM release increased as salt water was
added to fresh water phytoplankton• However, No effect on July Salinity
experiment – Different Seasons, Different Location in the river,
Different species (Salt-tolerant)
• Future Hypothesis/Testing– Different salt tolerance on other species of diatoms
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Thank You
-My Mentors Tawnya Peterson, Joe Needoba, and Karen Watanabe
-K-12 Director Karen Wegner-CMOP-ASE