by Piter Kehoma Boll
The open surface of the oceans may at first look like a large lifeless sheet. However, if you look closer, you’ll see that there is much more life there than you could imagine. And it does not only include the microscopic plankton that floats in the water column, but also large organisms that dwell right at the boundary between the water and the air. These creatures are called the neuston and come in several shapes and one of them is Lepas anserifera, or the common goose barnacle.
The common goose barnacle is found in tropical and subtropical waters all around the world. It belongs to the subclass Cirripedia, a peculiar group of crustaceans commonly known as barnacles. They live attached to the substrate and are hemaphrodites, both features that are uncommon among arthropods. Within the barnacles, the common goose barnacle belongs to the order Pedunculata, or goose barnacles, which are characterized by the presence of a stalk that attaches them to the substrate.
The substrate chosen by the common goose barnacle is almost exclusively floating material. This material, which includes sea weeds and all sort of debris, such as pieces of wood, coconuts or animal carcasses, rarely remains floating for a long time, either because its decay makes it sink or fall apart or because it ends up on the shore. Thus, the goose barnacle has to find a way to complete its life cycle very quickly, and that is what it does.
Goose barnacles start their lives as a planktonic one-eyed larva that, after five stages, develops into another larval form known as cyprid. The cyprid’s only purpose is to find a suitable surface to live and, once it finds it, it secretes a glycoproteinaceous substance that attaches it to the substrate by the head. It then develops into the adult animal and secretes a series of calcified plates that surrounds its body. The adults use their feathery legs (cirri) to capture food, mostly plankton, and carry it inside their shell.
Due to human activities, the amount of floating material on the ocean surfaces increased greatly. Thus, the number of available substrates for the goose barnacle to grow also increased, and so likely did its population. Unfortunately, the human-generated floating material also includes a lot of small plastic particles, and goose barnacles frequently ingest them together with food. Although the harm caused by ingesting plastic particles has not been assessed yet, they certainly do not improve the barnacle’s health.
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Goldstein MC, Goodwin DS (2013) Gooseneck barnacles (Lepas spp.) ingest microplastic debris in the North Pacific Subtropical Gyre. PeerJ 1: e184. doi: 10.7717/peerj.184
Inatsuchi A, Yamato S, Yusa Y (2010) Effects of temperature and food availability on growth and reproduction in the neustonic pedunculate barnacle Lepas anserifera. Marine Biology 157(4): 899–905. doi: 10.1007/s00227-009-1373-0
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** This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.