Seasons in the Sea - A month-by-month guide to Central California sea life

Section contents:

Kelp: Image credit-Tania Larson, USGS

Kelp beds

in August

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Diver-at-work symbol (c) Kim Fulton-Bennett This page under construction.
Here are some of the topics that will be covered in this chapter. More text and images will eventually be added to this section. Thank you for your patience.

Kelp bed events in August:

  • With less upwelling thus less nutrients in the water, as well as reduced sunlight, self-shading, and growth of epiphytes, giant kelp begins to grow less rapidly. In kelp beds that were especially damaged by winter storms, the kelp may not reach peak density until August.
  • Bull kelp releases spores after its stipes reach the surface. These spores form in darker patches on the blades of the kelp called "sori", which eventually "rot" of the plant, releasing the spores, typcially around dawn (when the sea is most calm). Porphyra nereocystis, an epiphyte on bull kelp, also spawns at this time of year.
  • Animal communities in the kelp canopy reach peak abundance and diversity. This includes masking crabs and attached animals such as ostrich-plume hydroids, which release young at this time of year.
  • Understory algae growing under giant kelp reach peak biomass before beginning to die out in late fall. By August there may be as many as four different layers of algae within the kelp forest: At the top is the canopy of giant kelp (the "big trees" of the kelp forest). Below the main canopy, large brown algae such as Laminaria and Pterygophora have grown tall enough (10- to 15-feet tall) to form a middle layer of "smaller trees." Beneath these, smaller (1- to 2-foot high) red algae such as Rhodymenia and Plocamium form a sort of underwater "shrubbery." Finally, coralline and foliose red algae form a low-growing "turf" several inches thick that covers any portion of the seafloor not occupied by other organisms.
  • Tne large annual understory kelp, Cystoseira osmundacea, releases gametes in fall. Many of these are consumed by purple sea urchins, but those that survive will sprout during next year's spring.
  • Larvae of the large, plumose anemone Metridium senile settles out on the seafloor in July-August. However, these larvae won't metamorphose into young anemones until some time between October and December.
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