Exploring the Intertidal

Check out the intertidal zone and its biodiversity!

Rhodophyta

These are the red algae - although they may look red, green, brown or purple! These are the most primitive eukaryotic algae. There are over 4000 species, more than all other types of algae combined! They contain chlorophyll a and b, and other pigments called phycobilins. They store sugars in the form of floridean starch. Red algae can live at deeper depths than any other type of algae. This is because red light is quickly filtered out by the water column, while green and blue light penetrate the most deeply. Red algae reflect red light, but absorb light in the blue and green spectrum to get energy, so they can survive where only a little bit of light penetrates. Some red algae have been found living as deep as 200m! Many of you may be familiar with the red algae, Porphyra, or nori. This is the type of algae used in sushi! A cell wall structure called carrageenan is used as an emulsifier in such common products as chocolate milk, pasta, and cottage cheese (click here for more about red algae).

Halosaccion glandiforme (sea sac)
Description: thin walled, elogated sausage-shaped sac, yellow-brown to red-purple
Range: Alaska to Mexico.
Habitat: Rocky shores, mid intertidal region
Cool Fact: Microscopic nematodes live in the sacs!

Bossiella sp. (Branching Coralline Algae)
Description: Pink to purple. Brittle, with jointed segments. Calcified. Range: Alaska to Mexico.
Habitat: Rocky shores, often in tidepools. Low intertidal to upper subtidal.
Cool Fact: This algae bleaches white after it dies. Makes some species look like a small skeleton!

Mazzaella splendens (Iridescent Seaweed)
Description:Purple to green colour. Flat blades, iridescent in sunlight.
Range: Alaska to California.
Habitat: Exposed, rocky shores. Low intertidal to 7m deep.
Cool Fact: The amazing iridescent look of this algae, especially when under water, is a site to see!

see more about Rhodophyta!

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