Why are deep-sea creatures often so much larger than their shallow-water relatives?
In the deep ocean, crabs, isopods, and amphipods can grow to bizarrely enormous sizes.
The answer
Deep-sea gigantism is a phenomenon where deep-ocean species grow significantly larger than related shallow-water species. The giant isopod (Bathynomus giganteus) can reach 50 centimeters, roughly 30 times the size of common woodlice. Several hypotheses explain this: cold deep-sea temperatures slow metabolism, allowing organisms to grow larger on less food; greater pressure may favor larger cell sizes; reduced predation pressure removes limits on body size; and Bergmann's rule, which links larger body size to colder environments. The phenomenon has been observed in amphipods, squid, sea spiders, and many other deep-sea taxa.
Source: Marine Ecology Progress Series
- deep sea gigantism
- giant isopod
- adaptation
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