Are dinoflagellates anchored to the sea floor?

Question

Forms of plankton move about in the water by drifting, but dinoflagellates cannot because they are anchored? Is that right?

Answer 1

Dinoflagellates are free-swimming. They have flagella that make them spin through the water. See a description here:

http://www.ucmp.berkeley.edu/protista/dinoflagmm.html

Answer 2

I don't think so because I thought flagella were used for locomotion. I'd give this question a go in Biology. They might know more.