Discovery of dense aggregations of stalked crinoids in Izu-Ogasawara trench, Japan.
Stalked crinoids are recognized as living fossils that typically inhabit modern deep-water environments exceeding 100 m. Previous records of stalked crinoids from hadal depths (exceeding 6000 m) are extremely rare, and no in-situ information has been available. We show here that stalked crinoids live densely on rocky substrates at depths over 9000 m in the Izu-Ogasawara Trench off the eastern coast of Japan, evidenced by underwater photos and videos taken by a remotely operated vehicle. This is the deepest in-situ observation of stalked crinoids and demonstrates that crinoid meadows can exist at hadal depths close to the deepest ocean floor, in a fashion quite similar to populations observed in shallower depths.
Oji
Tatsuo
T
Department of Earth and Planetary Science, The University of Tokyo, Hongo, Tokyo 113-0033, Japan. oji@eps.s.u-tokyo.jp
Ogawa
Yujiro
Y
Hunter
Aaron W
AW
Kitazawa
Kota
K
D000818:Animals; D017753:Ecosystem; D007448:Invertebrates / Q000502:physiology*; D007564:Japan; D009792:Oceans and Seas; D011156:Population Density