Alaska Sea Grant

Making a Quadrat

A quadrat is a frame used by marine biologists to perform counts of the density of organisms or the percentage of cover in a standard area. You may use quadrats made with 4 meter sticks for an area of one square meter, or you may use quadrats that are smaller. Hula hoops also work as quadrats if you have access to those. A scientist always knows the area of his or her quadrat, since it is used for sampling and making estimates of what will be found in a bigger area.

To make a ¼ square meter quadrat, use pvc tubing and elbow joints. Cut tubing so that the inside dimensions of your square measure 25 cm x 25 cm. You will need one quadrat for each group of sampling students.

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