You might think that the sea is forever the same, and you would be right, about the sea as a whole. But the surface of the sea changes with the seasons.
During the winter, the surface water has been collecting cold from the air, and in the spring, the cold, heavy waters sink to the bottom, and the warmer water, full of minerals that have been collected over the winter, rises to the top. The plants that make up plankton are dependent on those minerals, just as land plants are.
Diatoms need silica to make their shells, and also phosphorus. They must tide themselves over the winter as best they can. To do this, they are dormant, not demanding anything from the sea, that already denied them everything except the bare necessities of life.
In the autumn, a plant appears that shows its presence by glowing. This plant, Gonyaulax, is poisonous, and the Indians knew long before the white men came that when the sea began to glow red or green or blue, the tribal leaders forbid the catching of seafood, and they even set guards out to tell strangers about the poisonous plant. The reason why you can't catch seafood while Gonyaulax is there, is because fish eat it, and mussels get it in their livers. It reacts on people, so along the Pacific coast people know not to catch seafood in summer and fall.
More Later,
Bell
