1. Lab, Field, and Modeling Study
Influences of Changes in Salinity on Release of Carbon by Phytoplankton
Lab, Field, and Modeling Study
Jessica Wagner
Century High School
OGI & OHSU
Mentors:
Tawnya Peterson
Joe Needoba
Karen Watanabe
I’m Jessica Wagner I am going to be a senior at century high school next year and for the past 8 weeks I have been working at Ogi (Oregon Graduate Instuite) With my mentors Tawyna Peterson, Joe Needoba, and Karen Watanabe. My project studied the influnces of changes in salinity on release of caron by phytoplankton.

2. Water Samples, Carbon Model, Salinity Experiments
CMOP
Center for Coastal Margin Observation & Prediction
Field work
Modeling
In Situ Data
Lab Experiments
I worked within the CMOP organization. CMOP is the center for coastal margin observation and prediction. Our main aims are to study the coast and the connection between the climate and coasts as well as the human influences to ocean habitats. In order to do that we use 4 main methods –Field work, modeling, In Situ Data (sensors), and conducting lab experiments. Over the summer I used these methods on my project by utilizing water samples, creating a carbon model, and conduct salinity experiments. This is a picture of the Barnes one of the boats used to take water samples during CMOP Cruise’s.
Project Relevance
Water Samples, Carbon Model, Salinity Experiments

3. Focus/Question Estuary 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
A huge part of working with coastal observations involves estuaries. An estuary is where salt water and fresh water mix together. Because of the ongoing tide coming in and out there are a lot of changes in the salinity levels through out the days, months, and seasons. Knowing about the photosynthetic organisms in the Columbia River can provide information about how carbon and nutrients enter the estuary and becomes important wildlife habitat So my question was how does the change in salinity affect the freshwater diatoms (algea) as they hit the ocean.
Question: How does the change in salinity affect the growth rate of freshwater Diatoms?

4. CDOM Cast Data CDOM Colored dissolved organic matter
Phytoplankton release carbon naturally in their growth cycle but as they become more stressed they tend to realease more carbon into the water. To measure how much carbon is being realsed we measure the CDOM which is Colored dissolved organic matter. We use this because it is optically measurable by how much the light in the flourmeter can penetrate the water. Here is a picture of what a Flormeter looks like. It measures the CDOM in (RFU) which represents floursecese. And this graph shows one of the casts from a cruise. RFU vs. Depth and as you can see there is a lot more CDOM at the surface because the surface light is the idel place for phytoplankton to grow

5. Analysis of Variants (ANOVA)
Growth Rate vs.
Salinity
x 10 -3 5 10 15 20 25 30 35 40 45 50 2 4 6 8 12 14
Slopes
Conclusion: Growth rates are significantly different on the salinity range
Using all of the growth rates from each salinity Karen and I ran an analysis of variants to reject the null hypothesis that growth rate is not affected by salinity. Conclusion:growth rates are signifgantly different
Salinity (PSU)

6. 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
Growth rate is affected by salinity levels. So what does this mean for the estuary and carbon cycling? Salinity experiments that can show effect of changes in salinity on carbohydrates are needed because Microscopic observations show carbon being relased from the cell. so how do changes in salinty affect dissolved carbon release by phytoplankton
How do changes in salinity affect dissolved carbon release by phytoplankton?

7. Salinity Experiment -May
This Is the first Salinity experiment run by tawyna in may. The green dots are the control to show what the phytoplanton would natually do with ½ diluted water. The Blue dots have ½ salt water which is the shock. You can see here that after 24 hours there was a huge jump in CDOM production because the phyoplankton were mixed with salt water. And there was a slight drop in the freshwater cdom production because it was diluted. – CDOM naturally more in Freshwater because more phytoplankton live there. – Incubator on board with the river water flowing contatntly over it.
FW-Control
½ filtered fw
½ none filtered fw
SW-Shock
½ Filtered sw

8. Salinity Experiment-July
FW-Control
½ filtered fw
½ none filtered fw
SW-Shock
½ Filtered sw
We Wanted to recreate The May salinity Test that gave a closer look at what happened in the first 24 hours. So Tawnya and I set up an icubatior (in the picture )and relpicated experiment one. After doing hourly collections we found that the results were not the same as the previous expiremtent in this one there was a flat line. After looking closer we found anabeena in the samples (shown in the picture), and it Turns out annabeena adapts to salt.

9. Salinity affects growth of diatom
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
So in overall conclusion I found that salinity DOES affect growth of ditoms
CDOM release increases as salt water is added to fresh water phytoplankton
However there was no effet to the july salinity expirement we hypothesis that the results were not the same because samples were collected during different seasons, at different lactions in the river and because the species may have been different
Which brings up new questions for a future hypothesis
What are the salinity tolerances for different species of Diatoms?

10. -My Mentors Tawnya Peterson, Joe Needoba, and Karen Watanabe
Thank You
-My Mentors Tawnya Peterson, Joe Needoba, and Karen Watanabe
-K-12 Director Karen Wegner
-CMOP
-ASE
I’d Like to thank my mentors Tawnya, Joe, and Karen
Karen Wegner the K-12 director
CMOP
And ASE for the great expirence I’ve been able to have this summer