What are barnacles?

Image of gooseneck barnacles found in the rocky tide pools of Olympic Coast National Marine Sanctuary Photo credit: Elizabeth Weinberg, NOAA National Marine Sanctuaries

These aren’t dragon claws—they’re gooseneck barnacles! These filter feeders are discovered within the rocky tide swimming pools of Olympic Coast Nationwide Marine Sanctuary. Their shells are made up of a number of white plates that assist shield them from predators and from drying out.


Of the greater than 1,400 species of barnacles discovered on the earth’s waterways, the most typical ones are known as acorn barnacles. As anybody who’s ever maintained a vessel is aware of, eradicating barnacles requires some elbow grease (or a strain washer). That is why some boaters name them by their slang identify: “crusty foulers.”

How do barnacles persist with the undersides of vessels, to different sea life, to one another, and to just about something they arrive involved with? They secrete a fast-curing cement that’s among the many strongest pure glues recognized, with a tensile energy of 5,000 kilos per sq. inch and an adhesive energy of 22-60 kilos per sq. inch. The glue is so robust that researchers try to determine how it may be used commercially.

Barnacles like locations with a lot of exercise, like underwater volcanos and intertidal zones, the place they reside on sturdy objects like rocks, pilings, and buoys. Shifting objects like boat and ship hulls and whales are significantly susceptible to the pesky critters. Giant barnacle colonies trigger ships to tug and burn extra gas, resulting in vital financial and environmental prices. The U.S. Navy estimates that heavy barnacle progress on ships will increase weight and drag by as a lot as 60 p.c, leading to as a lot as a 40 p.c enhance in gas consumption!

Barnacles feed by feather-like appendages known as cirri. Because the cirri quickly lengthen and retract by the opening on the high of the barnacle, they comb the water for microscopic organisms. They shortly withdraw into their protecting shells in the event that they sense a possible risk. Barnacles secrete laborious calcium plates that utterly encase them. A white cone made up of six calcium plates kinds a circle across the crustacean. 4 extra plates type a “door” that the barnacle can open or shut, relying on the tide. When the tide goes out, the barnacle closes up store to preserve moisture. Because the tide is available in, a muscle opens the door so the feathery cirri can sift for meals.

What’s a glass sponge?

a glass sponge

Probably the most well-known glass sponge is a species of Euplectella, proven right here within the northwestern Gulf of Mexico. Generally referred to as the “Venus flower basket,” this sponge builds its skeleton in a manner that entraps a sure species of crustacean inside for all times.


Glass sponges within the class Hexactinellida are animals generally discovered within the deep ocean. Their tissues include glass-like structural particles, referred to as spicules, which are made from silica (therefore their title). Some species of glass sponges produce extraordinarily massive spicules that fuse collectively in lovely patterns to kind a “glass home”—a fancy skeleton that always stays intact even after the sponge itself dies. The skeleton of the glass sponge, along with numerous chemical substances, gives protection in opposition to many predators. Nonetheless, some starfish are recognized to feed on these uncommon creatures of the deep.

Most glass sponges stay connected to laborious surfaces and eat small micro organism and plankton that they filter from the encompassing water. Their intricate skeletons present many different animals with a house.

Probably the most well-known glass sponge is a species of Euplectella, referred to as the “Venus flower basket,” which builds its skeleton in a manner that entraps a sure species of crustacean inside for all times. This sponge typically homes two small, shrimp-like Stenopodidea, a male and a feminine, who stay out their lives contained in the sponge. The crustaceans breed, and when their offspring are tiny, they escape to discover a new Venus flower basket of their very own. The pair contained in the basket clear it and, in return, the basket gives meals for the crustaceans by way of its waste. The animals finally develop too massive to flee the sponge, so they’re pressured to “keep put” for the remainder of their lives.