Deep-Sea Research I 46 (1999) 1391}1415 Mesozooplankton in the Arctic Ocean in summer

• Main Authors: Delphine Thibault, Erica J. H. Head, Patricia A. Wheeler
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 1997
• Subjects: Amundsen Basin; Arctic; Arctic Ocean; Chukchi Sea; amundsen basin; Calanus hyperboreus; Chukchi; Nansen Basin; Phytoplankton; Copepods
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.582.3784; http://www.com.univ-mrs.fr/~botha/thibault et al, AOS94.pdf

The biomass, species and chemical composition of the mesozooplankton and their impact on lower food levels were estimated along a transect across the Arctic Ocean. Mesozooplankton biomass in the upper 200 m of the water column was signi"cantly higher (19}42 mg DW m~3) than has previously been reported for the Arctic Ocean, and it reached a maximum at ca. 873N in the Amundsen Basin. The lowest values were recorded in the Chukchi Sea and Nansen Basin, where ice cover was lower (50}80%) than in the central Arctic Ocean. In the deeper strata (200}500 m) of the Canadian and Eurasian Basins, the biomass was always much lower (4.35}16.44 mg DW m~3). The C/N (g/g) ratio for the mesozooplankton population was high (6.5}8.5) but within the documented range. These high values (when compared to 4.5 at lower latitudes) may be explained by the high lipid content. Mesozooplankton accounted for approx-imately 40 % of the total particulate organic carbon in the upper 100 m of the water column. Mesozooplankton species composition was homogeneous along the transect, consisting mainly of copepods (70}90 % of the total number). It was dominated by four large copepod species (Calanus hyperboreus, C. glacialis, C.,nmarchicus and Metridia longa), which together ac-counted for more than 80 % of the total biomass. According to measurements of gut pigment and gut turnover rates, the mesozooplankton on average ingested between 6 and 30 % of their body carbon per day as phytoplankton. Microzooplankton may have provided an additional source of energy for the mesozooplankton community. These data emphasize the importance of mesozooplankton in the arctic food web and reinforce the idea that the Arctic Ocean should