This is low tide in Great Cove’s intertidal zone on Friday (October 9). The “Rockweed” is living up to its name by clinging to its steadfast best friends.
There are several types of rock-anchored seaweed commonly called Rockweed. The one that you see here is our most abundant one, Knotted Wrack (Ascophyllum nodosum). Its “knots” are little air bladders that float its “blades” up to the surface to become waving fans in the rising tide.
Leighton Archive Image
Knotted Wrack and other Rockweeds are boarding houses for a variety of marine life at low and higher tides. They attach themselves to rocks with their “holdfasts,” toe-like growths that can paste themselves securely to hard surfaces. They are neither weeds nor true plants; they’re marine algae that host other lives and are, themselves, foods and ingredients for manufactured products, including fertilizer. Whether and how Rockweed should be commercially harvested is a controversial issue here. (Brooklin, Maine)