This summer, our group assisted Dr. Silliman and his grad student Katelin with their research regarding algal n-Alkane levels in Corpus Christi Bay. Their research dealt specifically with our bay’s surface mircrolayer, which is the very top layer of water molecules. Their goal is to track the health of Corpus Christi Bay over time and to hopefully be able to predict when our next algae bloom will occur.
Who We Are
What We Did
During our time working in Dr. Silliman and Katelin’s lab, we split our time between two places. Out in the field, where we helped collect samples of our bay’s surface microlayer, and in the lab, where we started the extraction process.
Using a TAMUCC alumna’s dock (with her approval), we were able to gather samples of Corpus Christi Bay’s surface microlayer using the following supplies:
- Glass plates (to gather the sample)
- Teflon squeegee
- 6 small glass vials (to hold the sample)
- 6 glass funnels
- Deionized Water
- Cooler with ice
The first step when collecting samples was to clean the supplies used during collection in order to ensure that no contamination took place. The vials and funnels we used were cleaned and ashed back in the lab, so while we were on the water we were in charge of cleaning and sanitizing the glass plates and squeegee. The first step to do this is to wash the plates and squeegee with ethanol and completely dry them with the KimWipes. We would then repeat the process with deionized water. After these steps, the plates and squeegee are ready to use for sample collection. These steps were taken after EVERY sample collected, in order to reduce the risk of cross contamination.
After all the supplies were cleaned and sanitized, we were ready to collect our sample. With a rope secured to the glass plate, one person slowly lowered it into the water while another person waited with a vial and funnel. When all the ripples dissipated, the glass plate was quickly brought out of the water and the water on the plate was collected in the vials. A majority of the water collected fell from the plate unassisted, but we used the teflon squeegee to gather remaining droplets left on the plate. Each sample got on average 10mL of water. The vial holding the sample was then capped, dated and placed in a cooler with ice. The cleaning and collecting process was then repeated six times.
Back in the lab, the extraction of n-Alkanes from previously collected samples took place. In order for Dr. Silliman and Katelin to study and record the number of microorganisms (including algal n-Alkanes) we first had to extract the microorganisms from the water sample. We completed this process using the following supplies:
- previous day’s water samples
- DCM (Dichloromethane)
- Separatory Funnel
- 6 new vials (to hold DCM mixture)
We started this process by removing the previous day’s water samples from the refrigerator and allowing them to come to room temperature. We then would pour the sample into a separatory funnel and flush out the original vial holding the sample with Dichloromethane (or DCM) in order to retrieve any leftover sample. The DCM used to flush out the vial was added to the funnel, along with 300 mL of n-Alkanes. Next, we mixed all the liquids in the funnel by shaking it for a minute to a minute and a half. Because DCM evaporates so quickly, the lid of the funnel had to be removed (or “burped”) every 10 shakes in order to relieve the pressure.
After mixing, the sample is left for about 2 minutes so the contents can separate. DCM is more dense than water is, so the water sits above the DCM in the separatory funnel. Using a new and clean vial, the DCM is taken from the funnel. It is very important that absolutely NO water is introduced into the new vial, as it contaminates the sample.
After the first extraction, 5mL of DCM is added to the separatory funnel and the process is repeated. This happens two more times before the sample is depleted of microorganisms. The sample is now labeled and put back into the refrigerator.
Dr. Silliman and Katelin are now ready to go ahead and separate the DCM from the microorganisms. Once they have separated the microorganisms, they will isolate the algal n-Alkanes and use these to track the health of the bay. They will also use this information to possibly predict when the next algae bloom will occur.
What We Learned
Through this lab we learned the important role that algae plays in our bay system and how it can grow out of control and hurt both the water and the organisms that depend and live in the water. By tracking the amount of algae n-Alkanes in the water, Dr. Silliman and Katelin hope to be able to predict when the next algae boom (or “red tide”) will occur. If we can have future knowledge of when the next red tide will occur, we can take preventative steps to counteract it.
This lab also taught us the importance of maintaining a clean and sanitized work area and supplies in order to ensure that all results received are as accurate and reliable as possible. In the lab, if contamination were to occur, all results yield from the contaminated supplies would have to be disregarded in order to retain the integrity of the lab. In the classroom, I will be sure to remember to tell my students how cross-contamination occurs and take the steps to ensure that such an event does not take place during experiments.
Questions We Have
How exactly will the results of this research predict the next algae bloom?
Would we have gotten different results if we had been out in the middle of the bay rather than close to the coast?
Can this same testing be done for fresh-water bodies of water?
How can we recreate a version of this experiment in the classroom?
What can we do as a community to ensure the health of our bay?
Connections to Teaching
Because this type of experimentation is rather complex, it would be hard to translate to a classroom with younger students. Therefore, I would use this opportunity to teach my students about nature and ecosystems. We could also tie in the idea of how humans affect the environments around us, but positively and negatively.
We can teach students how overfishing, runoff, pollution and recycling can affect the healthiness of our bay and the rest of the world. We must ensure that students understand that the Earth is our responsibility to care for and nurture in order to preserve it for future generations.