Sea Lettuce and Sitka Periwinkle
Scientific Name: Ulva lactuca and Littorina sitkana
Category: plant
Brief Description
A green marine macroalga known as sea lettuce and a small marine snail known as a periwinkle found in the rocky intertidal zone.
Characteristics
Ulva is characterized by thin, translucent green, ruffled blades that are only two cells thick. The periwinkle has a small, sturdy, rounded shell often with spiraling ridges.
Habitat
Rocky intertidal zones, tide pools, and mudflats.
When to Find It
Perennial, but sea lettuce is often more prolific in spring and summer.
Conservation Status
N/A
Ecological Role
Sea lettuce provides food for many marine organisms and serves as habitat; it can indicate high nutrient levels. Periwinkles are grazers that control algal growth on rocks.
Easily Confused With
Sea lettuce can be confused with Polyneura or Monostroma. Sitka periwinkle may be confused with the Checkered Periwinkle (Littorina scutulata), which is narrower.
Observation Tips
Look in tide pools and on rocks during low tide. Be careful not to step on sensitive organisms.
Interesting Facts
Sea lettuce is edible and rich in vitamins and minerals. The Sitka Periwinkle can survive for long periods out of water by trapping moisture inside its shell using a trapdoor called an operculum.
User Notes
Found on washington state beach