Tiny shells and spines

Well, I'm running out of time tonight, but I thought it would be fun to share this photo:

 

While doing intertidal surveys this past weekend, we noticed quite a few Sandcastle Worm (Phragmatopoma californica) tubes that were built primarily out of Foraminifera (informally called "forams") shells and small sea urchin spines.  [Forams are single-celled amoeba-like protists.]

More often, these worm tubes are made of darker colored sand grains (see the post "A close call" for examples of the more typical tubes).  But the tubes we saw this weekend really stood out — beautiful white foram shells cemented together with green and purple urchin spines and skeleton pieces.

I'm not sure if the forams are more common right now for some reason, but the worms sure did a good job at finding them and using them to build their tubes!