World Library  
Flag as Inappropriate
Email this Article

Deep-sea gigantism

Article Id: WHEBN0020975650
Reproduction Date:

Title: Deep-sea gigantism  
Author: World Heritage Encyclopedia
Language: English
Subject: Megafauna, Giant squid, Gigantism, Dwarfing, Foster's rule, Island gigantism, Insular dwarfism, Cephalopod size, Largest organisms
Publisher: World Heritage Encyclopedia

Deep-sea gigantism

In zoology, deep-sea gigantism, also known as abyssal gigantism, is the tendency for species of invertebrates and other deep-sea dwelling animals to display a larger size than their shallower-water relatives. Examples of this phenomenon include the giant isopod, the giant amphipod, the Japanese spider crab, the king of herrings (an oarfish of up to 12 m), the deepwater stingray, the seven-arm octopus, and a number of squid species: the colossal squid (up to 14 m in length), the giant squid (up to 13 m), Onykia robusta, Taningia danae, Galiteuthis phyllura, Kondakovia longimana, and bigfin squids. Some other very large fish found in the deep ocean, such as the Greenland shark and the Pacific sleeper shark, would not normally be considered examples because they sometimes visit the surface and are not larger than comparable species that spend more time in shallower water, such as the great white shark.


It is not known whether deep-sea gigantism comes about as a result of adaptation for scarcer food resources (therefore delaying sexual maturity and resulting in greater size), greater pressure, or for other reasons.

In the case of marine crustaceans, it has been proposed that the increase in size with depth occurs for the same reasons as the increase in size with latitude (Bergmann's rule): both trends involve increasing size with decreasing temperature.[1] The trend with depth has been observed in mysids, euphausiids, decapods, isopods, and amphipods.[1] The trend with latitude has been observed in some of the same groups, both in comparisons of related species as well as within widely distributed species.[1] Decreasing temperature is thought to result in increased cell size and increased life span, both of which lead to an increase in maximum body size (continued growth throughout life is characteristic of crustaceans).[1] In Arctic and Antarctic seas where there is a reduced vertical temperature gradient, there is also a reduced trend towards increased body size with depth, arguing against hydrostatic pressure being an important factor.[1]

Temperature does not appear to have a similar role in influencing the size of giant tube worms. Riftia pachyptila, which lives in hydrothermal vent communities at ambient temperatures of 2-30 C,[2] reaches lengths of 2.7 m, comparable to those of Lamellibrachia luymesi, which lives in cold seeps. The former, however, has rapid growth rates and short life spans of about 2 years,[3] while the latter is slow growing and may live over 250 years.[4]


See also


External links

  • Science Daily: Midgets and giants in the deep sea
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.

Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.