Friday, February 27, 2009

Diatom Investigations


Are there more dirrerent kinds of diatoms in the core A at 60 cm. than in core B at 5cm?


1. Make a smear slide from the 1st core at 60cm.
2. Look at the slide under a microscope.
3. Make another slide from the 2nd core at 5cm.
4. Repeat step two.
5.Compare the results


Slides, toothpicks, lake core, microscope, pencils, notebook


Core A 4 kinds 60cm. two slides
Core B no kinds 5cm 4 slides


Claim: Core A had more dirrerent kinds of diatoms thatn core B.

Evidence: We took two slides from core A and four slides from core B and core B still didnt have any diatoms. We found four kinds of diatoms in core A and no kinds in core B.

Reosoning: The reason we didnt find any diatoms in core B may be because when we took the sample in core B it was at 5cm. and thats younger than core B at 60cm and core B had more time to produce because the fact that it is older, and core B at 5cm. has not had as much as a chance to form diatoms as core A did because its younger at 5cm.

2 Further Questions: What would happen to the number of diatoms if we moved the sample to 5cm. in core A, and move the sample in core B to 15cm. extead of 5cm.?

What core has the most diatoms at 20cm. in core A and B?

Nick Mace, Danny Aldrich, Ty Honkala, Theo Jahnke

Lake Core Investigation

Hi our names are Amelia, Brittany, Jessica, and Madison. We are from Parkers Prairie High School. We are doing an investigation on diatoms in 8th grade Earth Science. For this investigation we are using a core sample 90 cm deep in Lake Adley.

Question: How many different kinds of diatoms are found at 30 and 90 cm from the surface of the core.

Variables Changed: Depth sample was taken at.
Variables Measured: Kinds of diatoms.
Controls: Core, amount of sediment taken for slide, and procedure.


  1. First we will take a core sample with a toothpick from 30 cm deep.
  2. Put sample on slide and add a drop of water, then put a cover slip on top.
  3. Then view the slide under a compound microscope and look for kinds of diatoms. (mark this in notebook.
  4. Take the same steps at 90 cm deep.


  • core/core sample
  • toothpick
  • slide
  • cover slip
  • compound microscope
  • water
  • diatom sheet
  • pipette


Diatoms found at 30 cm deep

  • Navicula/Pinnularia
  • Fragellaria
  • Cymbella
  • Aulacoseira
  • Amphora
  • Cyclotella

Diatoms found at 90 cm deep

  • Cyclotella
  • Asterionella
  • Hantzchia/Nitzchia
  • Melosiera
  • Navicula/Pinnularia
  • Synedra


Claim: There are mostly different diatoms at 30 and 90 cm, but some are the same. We found about the same number of different diatoms at each site.

Evidence: We found 7 kinds of diatoms at 30 cm. They are the following. Navicula/Pinnularia, Cyclotella, Aulacoseira, Cymbella, Amphora, Asterionella, & Fragellaria. At 90 cm we found Navicula/Pinnularia, Hantzchia,Nitzschia, Cyclotella, Melosiera, Synedra, & Asterionella. We found three diatoms consisting in both sites. They were Cyclotella, Asterionella, & Navicula/Pinnularia.

Reasoning: We believe that the reason we found three of the same diatoms at both sites is because those three diatoms can live in multiple environments. The reason there are different ones found at 30 and not 90 cm could be because the water environment was different when 90 cm was the top of the lake bottom.

Further Questions

1) How long ago was 90 cm deep on the core the surface.?

2) How are different diatoms formed?

Wednesday, February 25, 2009

Lake Core Investigation

Hello, our names are Ally, Dana, Courtney, and Derek, we are in earth science and we are studying lake cores about diatoms.

Question: How many diatoms are there at 60cm compared to 10cm?

Variable Measured- How many diatoms.
Variable Changed- The sample at 60cm compared to 10cm.
1. Get the cores out and materials ready.
2. Get sample at 60cm, and put on a slide
3. Look at the sample under the microscope and count the diatoms.
4. Wash the one sample off.
5. Get sample at 10cm and put it on a slide.
6. Count the diatoms and record data.
7. Wash that slide off and do all the data.
8. Repeat the steps at each spot 4 times and count the diatoms from each one and record data.

- 8 slides
- Core sample (at 60cm and 10cm)
-8 slide covers
-8 tooth picks
-Water dropper

Sample 1- At 10cm we found 3 diatoms, and at 60cm we found 2 diatoms
Sample 2- At 10cm we found 4 diatoms, and at 60cm we found 5 diatoms
Sample 3- At 10cm we found 2 diatoms, and at 60cm we found 2 diatoms
Sample 4- At 10cm we found 5 diatoms, and at 60cm we found 2 diatoms
Total- At 10cm there were 14 diatoms total and at 60cm we found 11 diatoms total!


Claim- we found that there are more diatoms at 10 cm then at 60 cm. there were 14 diatoms at at 10 cm an 11 diatoms at 60 cm.

Evidence- We took 4 samples at both 10 and 60 cm. The first sample at 10 cm had 3 diatoms the 2nd one had 4 diatoms, the 3rd one had 2 diatoms and the 4th one had 5 diatoms. totaling 14 diatoms. Our 4 samples at 60 cm at 2 diatoms on the first slide, 5 diatoms on the 2nd one, 2 diatoms on the 3rd one and 2 diatoms on the 4th one, all totaling 11 diatoms.

Reasoning- This may be becuase at 60cm it was older because it was closer to the bottom, so there would be older and less diatoms then there would be at 10 cm, because the soil at 10 cm is newer and closer to the top.

Further Questions-
1. Would the amount of diatoms differ if we took samples at 20 and 70 rather then 10 and 60 cm?
2. If we used 2 different core samples and took samples at 10 cm and 60 cm would the amount of diatomns differ between the two cores?

Tuesday, February 24, 2009

Lake Core Investigation

Hello, our names are Nick, Dylan, Eric, and RC. We are doing an investigation on Lake Core Sediments.This is our investigation!

Question: Does the size of a sediment change wirh the core depth of 70cm to 90cm?

Slide Cover Piece
Copound Microscope
Lake Core Samples

1.Gather up all of our materials or supplies
2.Put a tiny bit of the lake sample on slide from 70cm
3.Put 1 drop of water on slide
4.Put slide cover piece over sample
5.Put slide under compound microscope
6.Find sediment size
7.Repeat steps 2-6 but take sample from 90cm
8.Compare sizes of sediment
9.Write down what we see

Variables Changed:We tooks samples from 70cm and 90cm

Variables Measured: Sediment Sizes


We use the same materials

We did the same procedure

Same core sample

And how much we sampled


At 70cm we found out:

Slide 1: smallish shape, long, ovalis, clear, dark specks scattered

Slide 2: slightly bigger, more ovalish, alot of dark specks, less clear, clear spotlight

Slide 3: bigger then slides 1 and 2, less roundish, clear on 1 side, lot of specks, lines coming off of it

Slide 4: same size as #2, very ovalish, lots of specks, clear in center, 1 corner missing

At 90cm we found out:

Slide 1: very large, clear stripes, lots of dark specks, a pointed bottom, flat top

Slide 2: 1/2 size as 1st, egg shape, less clear, lots of specks, 2 bigger specks, another sediments close to it.

Slide 3: slightly smaller than 1st, clear spots on edge, lots of dark specks, design looks like finger print, green lines on it, turtle shape

Slide 4: Same size as 2nd, it has a turdish shape, has a point on the top and the bottom was round, 1 large darks spot, lots of sediments surronding it


We found out that at 90cm there are larger and less clear. Another thing is that in the 70cm mark almost all of the sediments were ovalish and at the 90cm they were a lot bigger and more of a wierd shape, such as eggish, coneish, and one even looked like a dog turd!!! we know it was dryer at 90 than at 70 because the sediments were larger at 90 than at 70. We know this because when it is dryer the sediments stick together than get blown into the lake. But when it is wet out and constantly raining the sediments stay apart from each other and get drained into the lakes when they are smaller.

2 Further Questions:

1. Are ther different types of diatoms at different depths?

2. Does the climate effect how long a diatom lives? If so how?

diatom study

Hi, our names are Alec, Mitchell, Brendon, and Shawn. And we are studying diatoms.

QUESTION: Are there more diatoms at 10cm. than at 70cm.

our procedure is 1. Walk over to the core. 2. Take tooth pick out of bag. 3. Take sample on slide. 4. Put sample on slide. 5. Put a drop of water on sample. 6. Smear sample and add coverslip. 7. Repeat three times at 10 cm and three times at 70 cm.8. Compare slides.

Variables: Change Depth
Variabled Measured: number of diatoms
Controls: same core, same amount at dirt

Conclusion: We found out that there where more diotoms at 70cm compared to 10cm. At 70cm there where 105 diatoms on three slides at 10cm there where 29 diatoms on three slides. at 70cm the time period could have been when they dumped sewage in the lake making more fertalizer for the plants and make more habitat for the diatoms.

2 Further Questions: 1. Does tempature effect the nubmer of diatoms? 2. Does the depth of water effect the number of diatoms?

Monday, February 23, 2009

Hi our names are LaDeanna, Brenna, Cole, and Dakotah. we were assigned to do a investigation on a sample core. this is our investigation!

Question: What is the difference in sediment size at 10cm compared to 90cm?

Procedure: 1. First we will take a sample from the core at 10cm. 2. Then we will create a slide for the 10cm sample. 3. Next we will take a sample fromt he core at 90cm. 4. Then we will create a slide for the 90cm. sample. 5. After, we will compare the two sediment samples under a microscope. 6. Finally, we will record our data in our notebook.

Materials: 1 spatula, 2 toothpicks, 2 slides, 2 coverslides, 1 microscopes.

Variable changed: 10 cm to 90 cm

Variable Measured: Sediment size

Controlls: same magnification, same size samples, same depths in core.


  • Sediments in 10cm are more clear than the 90 cm sediments.
  • Sediments at 90 cm are larger than sediments at 10 cm.
  • loosly formed ovals at the 10 cm & 90 cm measurements
  • sediments at 10cm are 2 times larger than the size of the pointer
  • sediments at the 90cm are 4 times larger than the size of the pointer


Claim-the 90cm sample we took has larger sediment than the sediments at 10cm

Evidence- the sediments in the 90cm sample were about 4 times the size of the pointer. The sediments in the 1ocm sample were only 2 times the size of the pointer.

Reasoning- We think that climate could determine the size of the sediments. We think so because when it's wet, sediments break off each other into smaller pieces, but when it's drier, they stay in one large sediment clump. So when it's dry, your going to have the larger clumps blow in because the smaller ones won't wash in due to lack of rain.

Futher Questions:

1. would the sediments sizes change, if we took our samples by the highway versus by a forest?

2. If the core was taken during the wetter season, would the sediments at 90cm have been smaller?