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mesobenthos

noun
  1. flora and fauna living at the bottom of seas 182 to 914 metres deep

Word Origin for mesobenthos

from meso- + Greek benthos depth of the sea
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012