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
| Type | : | ACL |
|---|---|---|
| Nature | : | Production scientifique |
| Au bénéfice du Laboratoire | : | Oui |
| Statut de publication | : | Publié |
| Année de publication | : | 2012 |
| Auteurs (7) | : | FOREST A STEMMANN Lars PICHERAL Marc BURDORF L ROBERT D FORTIER L BABIN Marcel |
| Revue scientifique | : | Biogeosciences |
| Volume | : | 9 |
| Fascicule | : | 4 |
| Pages | : | 1301-1320 |
| DOI | : | 10.5194/bg-9-1301-2012 |
| URL | : | <go to isi>://wos:000304049800004 |
| Abstract | : | 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 \mboxprimary 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 patterns co-varying in the same order of magnitude over the upper size range (> 1 mm ESD). Copepods < 1 mm were not well quantified by the UVP5, which estimated that only similar to 13-25 % of the assemblage was composed of copepods < 1 mm ESD compared with similar to 77-89 % from the net tow estimates. However, the biovolume of copepods was overwhelmingly dominated (similar to 93-97 %) by copepods > 1 mm ESD. Our results illustrate that the combination of traditional sampling methods and automated imaging techniques is a powerful approach that enabled us to conclude on the prevalence of a relatively high productivity regime and dominant herbivorous food web over the shelf when compared with the low-productive recycling system detected offshore. |
| Mots-clés | : | - |
| Commentaire | : | Times Cited: 6 stemmann, lars/E-6899-2011 6 |
| Tags | : | MALINA |
| Fichier attaché | : | - |
| Citation | : |
Forest A, Stemmann L, Picheral M, Burdorf L, Robert D, Fortier L, Babin M (2012) 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. Biogeosciences 9: 1301-1320 | doi: 10.5194/bg-9-1301-2012
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