Weeks 2, 3: Intro to Marine Biology/ Ocean Chemistry

Weeks 2 and 3: Intro to Marine Biology and Ocean Chemistry.

1.) Watch this short movie about plankton, then read chapter 2  in The Seaside Naturalist. Take notes on any points you feel you need to. Be sure that you understand the fundamental concepts of a food chain/web, and phylogenetic classification. Also, be familiar with the following terms: plankton, nekton, benthos, phytoplankton, zooplankton, holoplankton, meroplankton, nanoplankton, microplankton, macroplankton, and megaplankton. That is a lot of plankton! Why is it so important? Write a brief summary in your notebook.

2.) Scientists collect plankton using very fine mesh nets drug behind boats. (see photo here). Collect some live plankton using a plankton net (or by filtering a large volume of  fresh seawater through a coffee filter) and take a look at it under a microscope. Draw some sketches in your journal, one page for phytoplankton and another for zooplankton (make your best guess). Identify some if you can, but do not worry too much about  identification at this point (we will do more of that in the next few weeks). Just try to get a good variety of sketches and make them as accurate as you can, paying close attention to detail, using color where appropriate. Also, jot down any interesting behaviors you notice (speed, direction and manner of motion, foraging behaviors, organ functioning, etc).

3.) Check out some plankton images here:Plankton Image Database. Any of them look familiar? If so, which ones?

Ocean Chemistry

4.) Visit the website Ocean Chemistry and read the information there. Pay particular attention to the section on gases and be sure to watch the YouTube clip linked in that section.

5.) Obtain a sample of fresh  seawater for the following activity:

  • Using pH test strips, test the pH of the seawater and record this in your notebook.
  • Measure out 250 ml (or approximately 1 cup) of the seawater. Get a drinking straw and blow bubbles into the bottom of the container of seawater. Do this for several minutes. Try not to hyperventilate, ok?
  • Re-test the pH of the seawater.
  • Notice any changes? If not, keep blowing air through the water and re-testing until you do, and then record your results in your notebook.
  • Based on the information you read and the YouTube clip you watched, what specifically do you think is the cause of these pH changes? Write up your materials, methods, results and discussion in your notebook.

6.)Use your seawater  sample to determine the salinity of the body of water from which it was drawn (salinity is usually expressed as parts per thousand). Design a method yourself (you can do it!) and then write up your materials, methods and results in your journal. Is your value consistent with the values given for salinity in your book?

Alternative assignments for younger students:

Boil one liter of  seawater until all of the water is gone (Do not use your mother’s best pots! Use an empty soup/vegetable can from your recycle bin) and see how much salt is left after the water is gone. How much salt is there? Is there more or less than you thought there would be? Write your materials, methods and results in your notebook.

Perform the density experiments at this website: Test Density with a supersaturated solution. Do all three activities, answer any questions and write up your results in your notebook.



  1. Here is our week of experiments: http://happyheartsmom.typepad.com/natures_sweetness/2009/09/experimentation-sea-water-and-ph-salt.html

    I found my pH strips at the drug store 🙂 Happy weekend everyone!

  2. We are loving the study. My children are a bit younger but we live close to the ocean! Thanks for the great site!

    • I’ve added you to the blogroll!

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