(Copepoda) from a deep sediment-trap; Abundance and implications for ecological and biogeochemical studies

Ikenoue, Takahito*; Otosaka, Shigeyoshi*  ; Honda, Makio*; Kitamura, Minoru*; Mino, Yoshihisa*; Narita, Hisashi*; Kobayashi, Takuya 

We studied seasonal variations of the mesozooplankton swimmer community collected by a sediment trap moored at 873 m in the Kuroshio & Oyashio Transition region off the east coast of Japan from 5 August 2011 to 23 June 2013. The total flux of mesozooplankton swimmers varied between 0 and 11.1 individuals m-2 d-1, with a mean of 3.1 individuals m-2 d-1 during the sampling period. Among the Copepoda, Neocalanus cristatus was the most dominant taxon. The species composition of the swimmers closely reflected the mid-depth mesozooplankton of the Oyashio region. The fluxes of Neocalanus species reflected ontogenetic vertical migration, but may have been overestimates of active fluxes if they included dormant individuals that accidentally entered the sediment trap.