So, what is that icky looking stuff that’s coating our Central Coast beaches and surf zones?
It’s the remains of dead phytoplankton according to a Hatfield Marine Science Center scientist.
HMSC SeaGrant Educator Bill Hanshumaker says phytoplankton is at the bottom of the ocean food chain and floats about the water column waiting to be eaten. But when winds come out of the southwest for too long, it causes coastal waters to dive to the bottom (downwelling) which causes the phytoplankton to die. When the phytoplankton (“plant plankton”) dies, their cell sap tends to glue the skeletons together and to trap air. Surf and winds cause the mass to pile up in the familiar suds-like sea foam. If there is no wind, the seawater will have a brown, oily-like appearance.
When the winds turn back around and come from the northwest, the typical upwelling pattern returns, bringing up nutrients that feed the water column and the phytoplankton in it – thereby rejuvenating the sea going banquet.
There ya go.