Part 4—Search for Key Foraminifera: Indicators of Global Warming
In this fourth part, you will search the CHRONOS data portal for two particular Southern Ocean foraminifera species Acarinina praepentacamerata and Morozovella velascoensis. These species of planktonic foraminifera favor a warmer, more saline ocean. Thus, if the changes experienced at the PETM were global, you should find Acarinina praepentacamerata distributed throughout the Southern Ocean and Morozovella velascoensis distributed more broadly than in the tropics. Your CHRONOS search will yield all the IODP cores that contain both foraminifera from around 55 million years ago. You will then plot your data in Virtual Ocean to determine the spatial distribution of these species, and hence, determine if the PETM was indeed a global event.
Step 1 Search the CHRONOS Data Portal for Acarinina praepentacamerata
- Open the CHRONOS data portal (more info) in a new window.
- Click on Search by keywords in the middle of the page. A new search window will open.
- The Search window will load. Under the Search Menu heading, on the left side of the Chronos window, scroll down to the Janus subheading.
- Under the Janus subheading, select Samples by Taxa Occurrences. In the box on the right side, enter "Acarinina praepentacamerata" in the field Taxon Name; check the box Include only samples that have been dated, and click Submit.
Hint: Copy and paste this text Acarinina praepentacamerata into the box, since the search mechanism will only work if you spell correctly.
- Click on Submit to return results. You will see the word "loading". Note: depending on connection speed, this may take a few moments. Do not proceed until the search is complete.
Step 2 Download and Save the Data
- Once the data has loaded, you will be presented with several options for displaying and downloading your data. In the middle of the page there is a list to choose from. Scroll down until you see View Dataset as an Excel Spreadsheet (xls). You may need to expand the page in order to see the scroll bar.
- Click on View Dataset as an Excel Spreadsheet (xls). (Note: This will download the file to your downloads folder.)
- Save the file in a location where you can easily retrieve it for loading into Virtual Ocean. The default file name is "results.xls" You should rename "results" with a more appropriate, identifiable title, such as AP.xls. Keep the .xls extension.
- Repeat the steps above to search for and download the data for the taxa "Morozovella velascoensis". This time, however, be sure to rename the file MV.xls
- You should now have two Excel files, one for each of the taxa, saved on your desktop or documents folder.
Step 3 Upload the Data into Virtual Ocean
- If Virtual Ocean is not open, re-launch the program. Once it loads, make sure you have the Plate Boundaries and Seafloor Crustal Ages on the map as data layers.
- Click on the link to open the Virtual Ocean Homepage in a new window.
- Choose Datasets > Earthquakes and Plate Boundaries > Plate Boundaries (Bird 2003).
- Choose Basemaps > Seafloor Ages, Depths, Sediments and Spreading > Seafloor Crustal Ages (Earth Byte).
- Upload both foraminifera datasets into Virtual Ocean for further analysis. First, upload the Acarinina praepentacamerata dataset by selecting File > Import Table or Spreadsheet > From Excel-formatted (.xls or .xlsx) file...
- Navigate to the folder where you saved the file, single click on it and click Open.
- A new window will open. Check to make sure the format is correct. (Virtual Ocean will default to the recognized format.) Click OK.
- In the next window that opens, click the Color All button and use the sliders in the color chooser to select a bright color, such as red. Click OK.
- Click OK.
- Repeat steps 1 through 6 for the Morozovella velascoensis data and load into Virtual Ocean. Select a different color, such as blue.
- Orientate Earth so you can see the Southern Atlantic. Notice the locations of the two different foraminifera. Recall that you might expect to see M. velascoensis in the tropic and subtropics. Where are they found in the fossil record shown in these images?
- Move around Virtual Ocean to identify other locations for both A. praepentacamerata and M. velascoensis.
Consider the following questions:
These taxa of foraminifera prefer tropical conditions. Therefore, their presence in these typically colder regions indicates that the ocean waters must have been warmer at the time, indicating a Global climate change.
- Do you notice that both species are distributed in regions that are not typical? (i.e. A. praepentacamerata is in subtropics and M. velascoensis is in higher latitudes, which are usually colder.)
- What does this tell you about the temperature conditions of the global oceans?