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Be an Ocean Biodiversity Detective!

Part of Hall of Ocean Life.

Milstein Family Hall of Ocean Life Educator's Guide: Activity

Be an Ocean Biodiversity Detective!

The majority of organisms in the ocean are tiny invertebrates, protists, and algae. Although the ocean is vast in size, living space for these small organisms is limited to coastal areas and to surface waters where light penetrates—areas where food is plentiful and where there are surfaces on which to fasten and grow. Barnacles and bryozoa, for example, survive by attaching themselves to something larger, and then filter food from the water as it washes over them. Some organisms will find homes on larger moving animals, such as horseshoe crabs and whales. Still others may attach themselves to rocks, the pylons of a dock, or on seaweed.

Have you ever noticed the "necklace" of marine remnants left along the seashore at low tide? With careful observation this assortment of shells and algae, like jewels on a necklace, can reveal a wealth of tiny marine creatures.

In this activity students will collect and closely observe specimens that have washed ashore to recognize different kinds of small ocean organisms. Some organisms will leave parts of their bodies behind, such as shells, while others may leave behind clues such as holes.

What you need:

  • a visit to a sandy beach
  • bag or container for collecting specimens
  • magnifying glass
  • seashore guide - [Recommended: Seashore Life: A Guide to Animals and Plants Along the Beach. Golden Field Guide Series. New York: St. Martin's Press, 2002.]

What you do:

  1. Visit the seashore with your class at low tide for the best selection of washed up marine algae and invertebrate remains. Make a small collection of specimens to observe more closely in the classroom. Students should note the locations of their specimens. Specimens can include eel grass, seaweed, reeds, shells, driftwood, and sand dollars. Look for specimens that appear to have been used by other animals—these will be the most interesting specimens. Don't look for just the pristine and pretty objects. (Be careful not to uproot anything alive!)
  2. In the classroom: Now the detective work begins. Instruct students to closely examine their specimens and identify the primary organism—the original and usually largest organism on which other organisms may have attached. Make observations about