Size distribution of particles and zooplankton across the shelf-basin system in southeast Beaufort Sea: combined results from an Underwater Vision Profiler and vertical net tows

• Published in: Biogeosciences
• Main Authors: Forest, A., Stemmann, L., Picheral, M., Burdorf, L., Robert, D., Fortier, L., Babin, M.
• Other Authors: Université Laval Québec (ULaval), Laboratoire d'océanographie de Villefranche (LOV), Observatoire océanologique de Villefranche-sur-mer (OOVM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Mathématiques Jean Leray (LMJL), Centre National de la Recherche Scientifique (CNRS)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2012
• Subjects: [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography; Arctic; Arctic Ocean; Beaufort Sea; Mackenzie Shelf; Zooplankton; Copepods
• Online Access: https://hal.archives-ouvertes.fr/hal-03502681; https://hal.archives-ouvertes.fr/hal-03502681/document; https://hal.archives-ouvertes.fr/hal-03502681/file/bg-9-1301-2012.pdf; https://doi.org/10.5194/bg-9-1301-2012

International audience The size distribution and mean spatial trends of large particles (> 100 mu m, in equivalent spherical diameter, ESD) and mesozooplankton were investigated across the Mackenzie Shelf (southeast Beaufort Sea, Arctic Ocean) in July-August 2009. Our main objective was to combine results from an Underwater Vision Profiler 5 (UVP5) and traditional net tows (200 mu m mesh size) to characterize the structural diversity and functioning of the Arctic shelf-basin ecosystem and to assess the large-scale correspondence between the two methodological approaches. The core dataset comprised 154 UVP5 profiles and 29 net tows conducted in the shelf (< 100 m isobath), slope (100-1000 m) and basin (> 1000 m) regions of the study area. The mean abundance of total particles and zooplankton in the upper water column (< 75 m depth) declined exponentially with increasing distance from shore. Vertical and latitudinal patterns in total particle concentration followed those of chlorophyll a (chl a) concentration, with maximum values between 30 and 70 m depth. Based on the size-spectra derived from the UVP5 dataset, living organisms (0.1-10 mm ESD) accounted for an increasingly large proportion of total particle abundance (from 0.1 % to > 50 %) when progressing offshore and as the ESD of particles was increasing. Both the UVP5 and net tows determined that copepods dominated the zooplankton community (similar to 78-94 % by numbers) and that appendicularians were generally the second most abundant group (similar to 1-11 %). The vertical distribution patterns of copepods and appendicularians indicated a close association between \\mbox\primary\ production and the main grazers. Manual taxonomic counts and ZooScan image analyses shed further light on the size-structure and composition of the copepod community - which was dominated at similar to 95 % by a guild of 10 typical taxa. The size distributions of copepods, as evaluated with the 3 methods (manual counts, ZooScan and UVP5), showed consistent ...