benthos
noun
ben·thos ˈben-ˌthäs 
: organisms that live on or in the bottom of a body of water
Example Sentences
Recent Examples on the Web Researchers believed that the remains of animals may have accounted for the benthos' carbon needs. 
Eric Cheung, CNN, 15 Jan. 2020
Eric Cheung, CNN, 15 Jan. 2020 Word History
Etymology
New Latin, from Greek, depth, deep sea; akin to Greek bathys deep
First Known Use
1891, in the meaning defined above