The deep-sea zooplankton assemblage is hypothesized to have high species diversity, with low abundances of each species. However, even rare species may have huge population sizes and play a critical role in the dynamics of deep-sea environments. The Census of Marine Zooplankton (CMarZ) study sought to accurately assess zooplankton diversity in the mesopelagic and bathypelagic zones of the subtropical/tropical of the northwest and eastern sections of the Atlantic Ocean using integrated morphological and molecular analysis of large-volume samples to depths of 5,000m. The field surveys in April 2006 and November 2007 included scientists and students associated with the CMarZ. The cruise field work entailed at-sea analysis of samples and identification of specimens by expert taxonomists, with at-sea DNA sequencing to determine a barcode (i.e., a short DNA sequence for species recognition) for selected species. Environmental data and zooplankton samples were collected with 1-m2 and 10-m2 opening/closing MOCNESS (0-1000m and 1000-5000m, respectively), and with either a 0.25-m2 MOCNESS or a 0.5-m2 Multi-net above 1000m. More than 500 species were identified and more than 1000 specimens placed in a queue for barcoding on each cruise; several hundred species were barcoded at sea. For several taxonomic groups, a significant fraction of the region's known species were collected and identified. For example, in the northwest Atlantic 93 of 140 known ostracod species for the Atlantic Ocean were collected, 6 undescribed species were found, and the first DNA barcode for a planktonic ostracod was obtained. The deployment of trawls with fine-mesh nets to sample large volumes at great depths for small zooplankton confirmed that there is considerable species diversity at depth, with more species yet to be discovered

The success of these two CMarZ cruises was due to the collective efforts of Captain, Officers, Crew, and all members of the Scientific Party on the R/V Ron Brown and the FS Polarstern. The UConn Team DNA (Rob Jennings, Paola Batta Lona, Brian Ortman, Lisa Nigro, Leo Blanco-Bercial and Christopher Sweetman) carried out the at-sea sequencing. Nancy Copley and Dicky Allison were principally responsible for arranging logistical elements for the cruises. Support for the R/V Ron Brown and R/V Polarstern (XXIV/1) cruises came from NOAA Ocean Exploration Program Grant NA06OAR4600091, the Sloan Foundation, the Census of Marine Life (CMarZ) project, and the Alfred Wegner Institute

Special issue Species Diversity of Marine Zooplankton.-- 10 pages, 3 figures, 4 tables

Peer Reviewed