Scott Duarte, age 10, of Richmond, Va., or s question:

What is plankton?

Plankton is a rich seafood salad, the basic diet which supports all the fish and other creatures that dwell in the ocean. A cupful of the richest plankton looks like murky sea water, perhaps tinged with green or brown. This is because the food particles, or most of them, are too small for our eyes to see.

There are countless tiny one‑celled algae. These are simple forms of plant life which add a greenish or brownish tinge to the water. There are untold numbers of diatoms, little plants each living in a delicate shell of silica, There are hordes of microscopic crustaceans and other little sea animals. This filmy plankton is the basic food of many small and large see dwellers, fish who become the food for still. larger fish. Plankton is the only food eaten by the biggest animal in the world ‑ the blue ballaen whale.