Why do deep-sea creatures grow so much larger than their shallow-water relatives?
In the crushing darkness of the deep ocean, spiders, crabs, and isopods grow to monstrous sizes - and scientists are still debating why.
The answer
Abyssal gigantism - the tendency for deep-sea species to grow much larger than their shallow-water counterparts - remains one of marine biology's most intriguing puzzles. Giant isopods (Bathynomus giganteus) reach 50 centimeters, compared to 2-centimeter coastal relatives. Japanese spider crabs span 3.7 meters leg to leg. Proposed explanations include Bergmann's rule (larger bodies conserve heat in cold water), reduced predation pressure, greater oxygen availability in cold deep water, and adaptation to scarce food that favors efficient metabolisms. A 2006 study in the Journal of Biogeography found the strongest correlation with cold temperatures and high dissolved oxygen. The phenomenon occurs across crustaceans, sea spiders, amphipods, and cephalopods.
Source: Wikipedia
- abyssal gigantism
- deep sea
- marine adaptation
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