A lot of the seaweeds I find are filamentous and clump up into soggy wads when out of the water, so I’m experimenting with a technique for photographing them floating in a glass baking dish:
Works pretty well! I haven’t yet figured out what species that green mass might be.
I also like having the baking dish for scale. Without it, it’s hard to see the difference between these two Palmaria specimens:
Ascophyllum nodosum with hemiparasitic Vertebrata lanosa (syn. Polysiphonia lanosa.)
Haven’t been able to ID this one yet.
Filamentous red alga, probably Polysiphonia stricta
These last three were too big for the baking dish, so they are just laid out on the light table without water.
Agarum clathratum (Sea Colander)
Alaria esculenta (Winged Kelp)
and Saccharina latissima (Sugar Kelp).