Squidworm

Article By:

Osborn, Karen J. Department of Invertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington DC.

Last reviewed:2012

DOI:https://doi.org/10.1036/1097-8542.YB120266

The vast expanse of the oceanic water column (all the water below the surface and above the deep seafloor) supports a wide and fantastic array of animals. In many cases, little or nothing is known about these animals. The majority of life in the water column is dependent on productivity derived from sunlight in the surface waters; therefore, animal abundance and biomass generally decrease with increasing water depth. However, as one descends to within a few hundred meters of the seafloor, animal abundance and biomass increase again. This bottom few hundred meters is called the benthic boundary layer, the demersal zone, or the benthopelagic zone and is home to a diverse suite of animals who take advantage of the concentration of organic matter and other animals near the seafloor. This habitat is particularly difficult to study because it cannot be effectively sampled with either traditional water column or seafloor sampling equipment. Additionally, many of the animals found in the demersal zone, like the animals swimming and floating farther up in the water column, are fragile or gelatinous and thus are easily damaged by sampling gear. The development of vehicles capable of free operation in the deep water column has facilitated the discovery of many unusual animals in this habitat and has allowed a better understanding of the community found there because they allow one to directly observe the community and to selectively sample it. A fantastic example of these discoveries is Teuthidodrilus samae, known as the squidworm (see illustration), which is a large and flamboyant segmented worm that is common in the broad benthic boundary layer of the deep Celebes Sea (in the western Pacific Ocean).

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