Sea Lettuce – Ulva lactuca
Description: Ulva lactuca is a bright green sheet that closely resembles Monostroma spp. and Ulvaria spp. Ulva is two cells thick while Monostroma and Ulvaria are only one cell in thickness. Ulva can be differentiated from Monostroma and Ulvaria by the fingerprint test. If fingerprints can be seen through the translucent plant, it is Monostroma or Ulvaria. If they cannot, and the texture is similar to wax paper, it is probably Ulva.
The shape of Ulva is quite variable; some specimens are almost circular or oval while others are narrow and elongated. Plants have a fine, silky texture with waved or ruffled margins.
Habitat: Ulva is found in a variety of places-on exposed rocks, in tide pools, and in quiet shallow bays near the low tide mark. Ulva thrives in estuarine, nutrient-rich waters and may be dense in salt marshes and on mud flats where fresh water is abundant.
Foraging: Sea lettuce is an annual or a pseudo-perennial (most of the seaweed dies back and the plant is regenerated by a residual basal material). Young plants should be harvested in early spring for taste and tenderness. Blades are cut or plucked from rocks at low tide. Drifting plants may also be harvested if fresh.
Uses: Ulva is occasionally used fresh in salads, but is more often processed before eating. Ulva is prepared and eaten in the same manner as Porphyra (see page 14), but is not considered as much of a delicacy. Sea lettuce has also been used for burn treatments.
Processing: Sea lettuce may be washed in fresh water, drained, and dried for use as a seasoning (similar to Porphyra). It is also used fresh as a fodder or dried, milled, and added to animal feed.
Nutrients: Very high in iron. High in protein, iodine, aluminum, manganese, and nickel. Also contains starch, sugar, vitamin A, vitamin B1, vitamin C, sodium, potassium, magnesium, calcium, soluble nitrogen, phosphorous, sulfur, chloride, silicon, rubidium, strontium, barium, radium, cobalt, boron, and trace elements.