Abundance of microzooplankton determined during the EisenEx cruise ANT-XVIII/2 to the South Atlantic, supplement to: Henjes, Joachim; Assmy, Philipp; Klaas, Christine; Verity, Peter; Smetacek, Victor (2007): Response of microzooplankton (protists and small copepods) to an iron-induced phytoplankton bloom in the Southern Ocean (EisenEx). Deep Sea Research Part I: Oceanographic Research Papers, 54(3), 363-384


The dynamics, composition and grazing impact of microzooplankton were studied during the in situ iron fertilisation experiment EisenEx in the Antarctic Polar Frontal Zone in austral spring (November 2000). During the 21 day experiment, protozooplankton and small metazooplankton were sampled from the mixed layer inside and outside the patch using Niskin bottles. Aplastidic dinoflagellates increased threefold in abundance and biomass in the first 10 d of the experiment, but decreased thereafter to values twofold higher than pre-fertilisation values. The decline after day 10 is attributed to increasing grazing pressure by copepods. They also constrained ciliate abundances and biomass which were higher inside the fertilised patch than outside but highly variable. Copepod nauplii abundance also remained stable whereas biomass doubled. Numbers of copepodites and adults of small copepod species increased threefold inside the patch, but doubled in surrounding waters. Grazing rates estimated using the dilution method suggest that microzooplankton grazing constrained pico- and nanoplankton populations, but species capable of feeding on large diatoms (dinoflagellates and small copepods including possibly nauplii) were selectively predated by the metazoan community. Thus, iron fertilisation of a developing spring phytoplankton assemblage resulted in a trophic cascade which favoured dominance of the bloom by large diatoms.

DOI https://doi.org/10.1594/PANGAEA.558112
Related Identifier https://doi.org/10.1016/j.dsr.2006.12.004
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.558112
Creator Henjes, Joachim; Assmy, Philipp; Klaas, Christine; Verity, Peter; Smetacek, Victor
Publisher PANGAEA - Data Publisher for Earth & Environmental Science
Publication Year 2006
Rights Creative Commons Attribution 3.0 Unported
OpenAccess true
Language English
Resource Type Supplementary Collection of Datasets
Format application/zip
Size 38 datasets
Discipline Earth System Research
Spatial Coverage (20.647W, -48.593S, 21.169E, -47.668N); South Atlantic
Temporal Coverage Begin 2000-11-06T23:25:00Z
Temporal Coverage End 2000-11-29T15:33:00Z