I was at the beach today, playin in the surf, and I started to get a closer look at some seaweed. It occurred to myself and a friend that we really had know idea where it came from or what it even is. It didn’t have those vein-like things that leaves typically have. I didn’t see any stems or roots, just pieces of a more or less uniform smooth green seaweed material.
Where does it come from? It’s green which would suggest that it photosynthesizes - does that mean it grows above the water’s surface? How does it reproduce? what the heck is it and why is there usually so much of it?
Correct, the seaweed you saw was a type of marine algae. There are different kinds: some just look like lettuce leaves (laminaria?), some are like little airsacs that cling to rocks (fucus), and some look like gigantic inverted mops hundreds of feet tall (kelp). Some seaweeds have been commercially harvested from the sea for decades or more (dulse ?sp? in Ireland for example), and we ranch and farm marine algae as well.
Carrageenan is a thickening agent frequently used in ice cream and ice cream-like desserts. It’s made from seaweed.
Here’s a fabulous page about the seaweeds of New England. It describes the different seaweeds and tells you how to harvest and prepare them if you’re foraging (their term for hunting the wild seaweed). It even has some seaweed recipes, like Sea Pickles and Candied Kelp. I can’t vouch for how any of these dishes taste, but I think most things can be made edible if you add enough sugar.