Lindsey's Crevice

Ocean temp: 9 degrees Celsius (48.2 F)
Ocean salinity: 30.8 ppt


Lindsey's Crevice is a vertical low intertidal bedrock wall that faces west toward the shore. It is 0.3 meters (1 foot) high and about 4 meters (12 feet) long. There are tidepools at the base of the wall, which always contained water. There were also small cracks and crevices along the wall that provide refuge for many animals. This wall was accessible during the lowest tides of the year (-3.0), but may not be accessible during most low tides.

Completely covered with leafy algae, the wall is home to a wide diversity of species. Lindsey's Crevice faces the shore and generally does not receive strong wave action. This allows more algal growth than in other more exposed areas. Algae, such as sea lettuce (Ulva) and Hedophyllum, further reduce water flow, protecting animals that live on or near the wall. They also create more surface area for epifaunal animals such as bryozoans. Limpets and snails were dominant along the wall, while the tidepools along the base had many species of sea anemones and tubeworms.

The sea anemones found at the base of the wall and in the tidepools are mostly sessile. The lower, pedal disk of these animals have spirocysts, cells that contain a capsule with a long adhesive thread in it.  These cells attach the pedal disk to the substrate. To move, some sea anemones may glide slowly on the pedal disk. Others crawl on the side of their column, or walk using their tentacles. A few species, such as Stomphia coccinea, can lift off and swim, using back and forth motions of the column, in response to the touch of a predator.

The nemertean worm Paranemertes peregrina has a most amazing adaptation for carnivory. All ribbonworms possess an eversible proboscis.  In the enopla ribbonworms, the proboscis has a sharp, calcium carbonate spike at the end of it. Through the contraction of a sealed internal fluid-filled space, a strong hydrostatic pressure causes the proboscis to shoot out of the anterior end of the animal, impaling its prey with the sharp spike, or stylet. The stylet is similar to a shark's tooth, in that replacement stylets are continually forming. Paranemertes worms prey mostly on other worms, primarily polychaete worms, which can be 3 or 4 times the size of the predator. They impale the polychaete and then quickly sever the worm using the proboscis as a noose. They then swallow the polychaete relatively whole in a display of bravado rarely matched in the animal kingdom.

The orange sea cucumber (Cucumaria miniata) is free spawning--individuals are either male or female.  Eggs and sperm are released in early March to mid May in calm waters between tide cycles where fertilization occurs in the water column. At this time green eggs may be seen floating off shore. Sperm is white or pink.

Animals found at Lindsey's Crevice:




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