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The ocean floor is not all flat but has submarine ridges and deep ocean trenches known as the hadal zone. [6] For comparison, the pelagic zone is the descriptive term for the ecological region above the benthos, including the water column up to the surface. At the other end of the spectrum, benthos of the deep ocean includes the bottom levels ...
The hydrothermal vents where these crabs live are typically short lived, lasting from 10 to 100 years. These are extreme environments, with high temperatures, high concentrations of sulphides, heavy metals, carbon dioxide and an acidic environment. [8] At this depth there is also limited access to light making photosynthesis nearly impossible.
Crabs of the family Panopeidae are all free-living (not commensal or parasitic), [2] and typically live in soft-bottomed parts of the ocean, [3] lending them the common name "mud crabs" (a name also shared by other organisms). They burrow into the sediment and feed on a variety of marine invertebrates.
Crabs are decapod crustaceans of the infraorder Brachyura (meaning "short tail" in Greek), which typically have a very short projecting tail-like abdomen, usually hidden entirely under the thorax. [a] They live in all the world's oceans, in freshwater, and on land. They are generally covered with a thick exoskeleton. They generally have five ...
The crabs go through five zoeal larval stages and one megalops stage before settling to the bottom in their first juvenile stage. [4] The free-swimming stages typically take three months to four months, [3] although in Alaska crabs may remain larvae for up to a year. [7] Sexual maturity is reached after about 12 molts or two years. [9]
The crabs can travel up to 1.46 km (0.91 mi) in a day, and up to 4 km (2.5 mi) in total. [4] Only a few land crabs, including certain Geosesarma species, have direct development (the mother carries the eggs until they have become tiny, fully developed crabs), and these do not need access to water to breed.
Coconut crabs live alone in burrows and rock crevices, depending on the local terrain. They dig their own burrows in sand or loose soil. During the day, the animal stays hidden to reduce water loss from heat. The coconut crabs' burrows contain very fine yet strong fibres of the coconut husk which the animal uses as bedding. [43]
Similarly, snow crabs likely will have an adverse effect on the native species of the Barents Sea. [6] Snow crabs are found in the ocean's shelf and upper slope, on sandy and muddy bottoms. [3] They are found at depths from 13 to 2,187 m (43 to 7,175 ft), but average is about 110 m (360 ft). [7] In Atlantic waters, most snow crabs are found at ...