And as the weather changes with the changing seasons, so does the kelp forest. Spring is the season of renewal in the forest. March winds blow surface waters offshore, and cold, nutrient-rich water wells up from the depths, fertilizing plants of all sizes. The sunlight of lengthening days coaxes new growth from red algae on the forest floor, while new fronds of giant kelp sprout from old holdfasts , reaching toward the surface as they grow. By June, gaps in the kelp canopy have closed, cutting off light to the forest floor.
Spring spurs the growth of other algae, too.
Countless billions of microscopic plant plankton turn the water murky green as they drift through the open waters of the bay. They, in turn, fuel a population explosion of tiny animal plankton , which graze on the plants and prey on each other. Many of these are the larvae of fishes, crabs, sea stars, bryozoans and other kelp forest dwellers. By the end of summer, the forest is lush and bustling with life. With less sunlight and fewer nutrients, kelp growth slows.