Specimens

What are Seaweeds?

Most algae live in water, and even though many photosynthesize to make their own food, only some of them are classified as plants. Seaweeds are macroalgae (algae large enough to see without a microscope) that live in the ocean and can be described as red, green, or brown.

Nereocystis luetkeana

Bull kelp

Brown seaweeds, like this kelp, are a distinct group and have a separate ancestor to all other seaweeds. Kelps are usually made up of a holdfast, stipe, and blade(s).

Nereocystis luetkeana

Bull kelp

Articulated and crustose coralline algae

on rock

Crustose coralline algae

on unidentified substrate

Crustose coralline algae

on shell

Crustose coralline algae

on rock

Articulated and crustose coralline algae

on shells

Corallines are a special group of red algae containing calcium carbonate. You can see two types here, crustose coralline algae (pink bubblegum crusts) and articulated coralline algae (upright, segmented, and branching).

Crustose coralline algae

on bottle

Corallina vancouveriensis and crustose coralline algae

on rock

Look closely. Can you see some crustose coralline on this articulated coralline? The crust is probably Neopolyporolithon reclinatum, a picky species which only grows on articulated corallines.

Crustose coralline algae

on rock

Seaweed Science

Do you know your delicate sea lace from your coarse sea lace? Seaweeds can be tricky to identify, so researchers use many tools including online keys and identification apps.

Pyropia torta

Teal nori

Pyropia torta

Teal nori

Postelsia palmaeformis

Sea palm kelp

Postelsia palmaeformis

Sea palm kelp

Pyropia abbottiae

Black seaweed

Pyropia unabbottiae

Diverse Habitats

You can find seaweeds in many different habitats. Some, like this rockweed and feather boa kelp, grow near rock pools along the shore. Others grow in deeper waters and reach up to the surface to photosynthesize. A few inflate with air to float on the surface of the ocean.