Details

Title

Characterisation of large zooplankton sampled with two different gears during midwinter in Rijpfjorden, Svalbard

Journal title

Polish Polar Research

Yearbook

2017

Volume

vol. 38

Numer

No 4

Publication authors

Keywords

Abundance and size ; Arctic ; Polar night ; Rijpfjorden ; Vertical distribution patterns ; zooplankton

Divisions of PAS

Nauki o Ziemi

Coverage

459-484

Abstract

During a midwinter cruise north of 80oN to Rijpfjorden, Svalbard, the composition and vertical distribution of the zooplankton community were studied using two different samplers 1) a vertically hauled multiple plankton sampler (MPS; mouth area 0.25 m2, mesh size 200 μm) and 2) a horizontally towed Methot Isaacs Kidd trawl (MIK; mouth area 3.14 m2, mesh size 1500 μm). Our results revealed substantially higher species diversity (49 taxa) than if a single sampler (MPS: 38 taxa, MIK: 28) had been used. The youngest stage present (CIII) of Calanus spp. (including C. finmarchicus and C. glacialis) was sampled exclusively by the MPS, and the frequency of CIV copepodites in MPS was double that than in MIK samples. In contrast, catches of the CV-CVI copepodites of Calanus spp. were substantially higher in the MIK samples (3-fold and 5-fold higher for adult males and females, respectively). The MIK sampling clearly showed that the highest abundances of all three Thysanoessa spp. were in the upper layers, although there was a tendency for the larger-sized euphausiids to occur deeper. Consistent patterns for the vertical distributions of the large zooplankters (e.g. ctenophores, euphausiids) collected by the MPS and MIK samplers provided more complete data on their abundances and sizes than obtained by the single net. Possible mechanisms contributing to the observed patterns of distribution, e.g. high abundances of both Calanus spp. and their predators (ctenophores and chaetognaths) in the upper water layers during midwinter are discussed.

Publisher

Committee on Polar Research ; Polish Academy of Sciences

Date

2017.12.15

Type

Artykuły / Articles

Identifier

ISSN 0138-0338 ; eISSN 2081-8262

DOI

10.1515/popore-2017-0023

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