Magnitude of mesozooplankton variability: a case study from the Marginal Ice Zone of the Barents Sea in spring

Zooplankton was studied on eight stations in the marginal icezone (MIZ) of the Barents Sea, in May 1999, along two transectsacross the ice edge. On each station, physical background measurementsand zooplankton samples were taken every 6 h over a 24 h periodat five discrete depth intervals. Cluster analysis revealedseparation of open water stations from all ice stations as wellas high similarity level among replicates belonging to particularstation. Based on five replicates per station, analysis of variance(ANOVA) confirmed significant differences (P < 0.05) in abundancesof the main mesozooplankton taxa among stations. Relations betweenthe zooplankton community and environmental parameters wereestablished using redundancy analysis (CANOCO). In total, 55%of mesozooplankton variability within studied area was explainedby eight variables with significant conditional effects: depthstratum, fluorescence, temperature, salinity, bottom depth,latitude, bloom situation, and ice concentration. GLM modelssupported supposition about clear and negative relationshipbetween concentration of Oithona similis, and overall mesozooplanktondiversity. The analyses showed a dynamic relationship betweenmesozooplankton distribution and hydrological conditions onshort-term scale. Furthermore, our study demonstrated that variabilityin the physical environment of dynamic MIZ of the Barents Seahas measurable effect on the Arctic pelagic ecosystem.