Friday, January 16, 2009

Diatom Investigation Results

Hi, My name is Anna! I am in 11th grade and for Earth Systems my teacher had me do an investigation with diatoms.

Question: What is the difference in species of diatoms in the different layers?

Materials: Core sample, toothpicks, microscope, glass slide, pencil, notebook, meter stick, cover slips, permanant marker, water, eye dropper

Procedure: 1. Take the core sample out of the wrapping. 2. Use the toothpick to scrape some of the sample up. 3. Spread what you have on the toothpick over the glass slide. So it is coated but not to thick. 4. Put one drop of water and place a cover slip over it. 5. Mark sample with the marker at 5 cm. 6. Put the slide under the microscope and see what you find. 7. Write down and see what you find in your data table. 8. Repeat steps 2-7 for 45cm, 95cm too.


Types of Diatoms Found:

5 cm-Tabellaria, Navicula, Cocconeis, Meridon, Pinnularia

45 cm - Tabellaria, Cocconies, Fragellaria, Surirella, Melosira, Diatoma

95 cm - Tabellaria, Surirella


I found out that from all three layers where I took samples, there was only one diatom that was in all of them. It was the Tabellaria diatom which is in the Pennales class. Other than that the layers had very different species of diatoms.

In 5 cm, I found Tabellaria, Navicula, Cocconeis, Meridon and Pinnularia. In 45 cm, I found some of the same ones which were Tabellaria and Cocconeis. The different ones I found were Fragellaria, Surirella, Melosira and Diatoma. In 95 cm, there were not any different species. It had Tabellaria, which was found in 5 cm and 45 cm, and Surirella, which was found in 45 cm. The reasons I think my data turned out the way it did is because I just used wet slide samples and I didn't use any chemicals to remove dirt. I think this is shy at 95 cm I did not find many diatoms. I also think I did not make the layer of sediment on the slide thin enough.

Further Questions:

1. How does a new species of diatoms come about?

2. What kind of story do amounts of diatoms tell?