Science as Inquiry

  • Ability to do scientific inquiry (5-8, 9-12)
  • Understanding of scientific inquiry (5-8, 9-12)

    Life Science

  • Diversity and adaptations or organisms (5-8)
  • Structure and function in living systems (5-8)
  • Behavior of organisms (9-12)

    Science and Technology

  • Understandings about science and technology (5-8, 9-12)

    Science in Personal & Social Perspectives

  • Populations, resources and environments (5-8)
  • Risks and benefits (5-8)
  • Science and technology in society (5-8)
  • Personal and community health (5-8, 9-12)
  • Environmental quality (9-12)
  • Science and technology in local, national and global challenges (9-12)

    History and Nature of Science

  • Science as a human endeavor (5-8, 9-12)
  • Nature of scientific knowledge (5-8, 9-12)
  • seaweed aquaculture
    Photo courtesy of NOAA.
    written by Carol Hopper Brill and Lisa Ayers Lawrence

    Seaweed has been traditionally harvested in Europe, Asia and the Pacific Islands for thousands of years, and today harvesting seaweed is big international business. Not only are seaweeds harvested for direct consumption of the plant itself, but also for the intriguing and functional chemicals or "natural products" they produce. Many of these compounds have application for human use. Chemicals derived from seaweeds are used in medicines, food and beauty products, and industry. That's right, the ice cream and chocolate milk in your fridge, the lipstick in your makeup bag, and even the toothpaste you brushed your teeth with this morning may all be made with seaweed extracts.

    How does seaweed end up in both whipped topping and paint? Most seaweeds are algae -- aquatic plants that lack roots, stems or leaves. Algae are divided into three main types: red, brown and green. From each of these types of algae, scientists have been able to identify and isolate compounds that can make foods creamier and paint thicker. Red and brown algae produce phycocolloids ("phyco" = seaweed, "colloid" = glue) that include agar, alginate and carrageenan. Green algae produce the antioxidant beta carotene which is a precursor to vitamin A.

    The use of these compounds in food products took off in the second half of the 20th century as the demand for prepared foods increased. Compounds like carrageenan improve the quality of the food and help to stabilize it, making the item more appealing to consumers. Currently the import and export of seaweed is a $200 billion business, with the United States importing nearly $50 billion worth each year. And as more nations become developed, the need for more prepared foods and pharmaceuticals will increase the demand for seaweed compounds.

    To meet this demand, selected marine algae are grown, harvested and processed on large scales around the globe and at home. Even high schools are getting in on the act. Bridgeport Regional Vocational Aquaculture School in Connecticut has been working with Connecticut Sea Grant researcher Dr. Charles Yarish to improve aquaculture techniques for the red alga, nori (see picture above). Students and scientists are cultivating nori next to salmon aquaculture pens. The red algae remove from the water excess nutrients produced by the fish, and in turn use those nutrients to grow.

    Who harvests and imports seaweeds? The actvitiy below will help you answer this question.


    This data activity offers two levels of inquiry (from simpler and less time consuming to more complex and time intensive) and a lab extension activity. Teachers should start with Level 1 below, and continue as appropriate for their students and their prep and lesson time available.

    We'll use United Nation's Food & Agriculture Organization (FAO) statistical site to research fishery production of marine algae around the world. A report by TradeDataNet provides charts on countries that import and export algae and the average import prices.

    Who Harvests Seaweeds?

    What were reported world seaweed harvests in 2001? (Note: We're using 2001 so that we can compare data sets from two different sources). Using the FAO Stats we can investigate the world harvest of seaweeds:

  • What was the total world harvest of seaweed in 2001? Of brown seaweed? Of green seaweed? Of red seaweed?
  • Now, you can compare the total world harvest of all three seaweed types and create a pie chart that compares the 2001 harvest in a graphical way.

    Next, let's focus in on the most significant harvests and where they come from. Which countries harvested the most red seaweeds and brown seaweeds in 2001?

    From your results, make a list of the top six countries in brown seaweed production and in red seaweed production.

  • For graphing skills opportunities:

    Why might the top producers of brown seaweeds be somewhat different from the top red seaweed producers? Hint: Check out the biology of brown and red seaweeds, where do most of them grow?

    Who imports seaweeds?

    Which countries import the most seaweeds? Many countries import seaweeds, including the United States. Use TradeData International's report to research who buys the most.

    Visit the Smithsonian Ocean Planet exhibition website and print the list of the products containing algae. Imagine that you are at a school similar to Bridgeport and have a seaweed aquaculture facility. Pick a type of seaweed that your school might grow, determine what products might come from that seaweed, and research which countries might be interested in importing seaweed from you. Design a marketing campaign to sell for your seaweed.

    Go to Level 2 Data Activity

    Seaweed products provide just one example of how chemicals derived from marine organisms have become increasingly important in our lives. The sea's biodiversity and extreme environments continue to attract scientists as they search for new compounds, organisms and biotechnology opportunities. The treasures we can extract from the sea should also heighten our efforts to sustain healthy marine ecosystems and their full complements of marine life.

    For more related resources, visit the Bridge's Marine Algae page.

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