In the pink

I see them often on the beach at low tide: small, white, randomly branched, calcareous tubes. When I pick them up, cautiously, they start to break up. Put in a container to bring home, they make the trip in pieces.

I took a photo of this one as found, without touching it.

Coralline red algae. A seaweed, recently deceased.

These small algae are red or purplish pink, but turn white when they die. This one is still fresh, with only the tips of the branches showing white.

The algae deposit calcium carbonate in their cell walls, which helps to protect them from browsing by snails and other animals. To be flexible in the surging tides and waves, each little node is separated by non-calcareous "knees"; when the alga dies, these knees quickly deteriorate, and the nodes begin to scatter themselves across the beach.

Alive, the algae stay attached to the sea floor by holdfasts. Wikipedia has a photo of one, still alive, still attached to its rock.

Photo by David R. Ingham, California.

In this specimen, the nodes are shorter and fatter; it is probably a different species,even a different genus, but identification is almost impossible except during the reproductive stage, and then only with a microscope. (Kozloff, p. 158)

I picked up my find, gently. It survived. Because it was still pink.