Polar Biology

, Volume 29, Issue 11, pp 950–962

The autumn mesozooplankton community at South Georgia: biomass, population structure and vertical distribution

Original Paper

DOI: 10.1007/s00300-006-0136-3

Cite this article as:
Ward, P., Shreeve, R. & Tarling, G.A. Polar Biol (2006) 29: 950. doi:10.1007/s00300-006-0136-3
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Abstract

Mesozooplankton were sampled at shelf and oceanic stations close to South Georgia, South Atlantic during austral autumn 2004 with a Longhurst Hardy Plankton Recorder. Onshelf biomass ranged from 2.18 to 5.75 g DM m−2 (0–200 m) and was dominated by the small euphausiid Thysanöessa spp. At the oceanic stations (10.57–14.71 g DM m−2, 0–1,000 m) large calanoids, principally Rhincalanus gigas comprised ∼47–52% of biomass. Here Calanus simillimus was still active and reproducing in surface waters (0–11.2 eggs fem day−1) but R. gigas and Calanoides acutus were largely resident in the warm deep water and undergoing their seasonal descent. A comparison with spring and summer data indicated increased abundance and biomass from spring through to summer followed by a decline towards autumn particularly over the shelf. Autumn values in oceanic waters differed little from summer. Mesozooplankton biomass in the surface 200 m of the oceanic stations as a proportion of that found in the top 1,000 m ranged from 63 to 78% of the total in spring and 62–73% in summer, but was only 23–29% of the total in this study, following redistribution down the water column.

Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  • Peter Ward
    • 1
  • Rachael Shreeve
    • 1
  • Geraint A. Tarling
    • 1
  1. 1.British Antarctic Survey, Natural Environment Research Council CambridgeUK

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