Surface diatom community composition and species-specific contribution to carbon biomass, live and empty cell abundances over the Kerguelen region in the Southern Ocean (KEOPS 2 program) ...

• Main Authors: Lasbleiz, Marine, Leblanc, Karine, Armand, Leanne K, Quéguiner, Bernard
• Format: Dataset
• Language: English
• Published: PANGAEA 2016
• Subjects: Event label; Latitude of event; Longitude of event; Elevation of event; DATE/TIME; Bottle number; DEPTH, water; Radiation, photosynthetically active; Diatoms; Diatoms, biomass as carbon; Actinocyclus curvatulus; Asteromphalus hookeri; Asteromphalus hyalinus; Asteromphalus parvulus; Azpeitia tabularis; Chaetoceros spp.; Chaetoceros spp. resting spores; Chaetoceros aequatorialis; Chaetoceros atlanticus; Chaetoceros atlanticus var. neapolitanus; Chaetoceros bulbosus; Chaetoceros convolutus; Chaetoceros concavicornis; Chaetoceros criophilus; Chaetoceros decipiens; Chaetoceros dichaeta; Chaetoceros flexuosus; Chaetoceros mitra; Chaetoceros peruvianus; Chaetoceros radicans; Chaetoceros socialis; Corethron inerme; Corethron pennatum; Coscinodiscus sp.; Dactyliosolen antarcticus; Dactyliosolen tenuijunctus; Eucampia antarctica; Fragilariopsis kerguelensis; Fragilariopsis pseudonana; Fragilariopsis separanda; Guinardia cylindrus; Leptocylindrus danicus; Leptocylindrus mediterraneus; Membraneis sp.; Membraneis challengeri; Membraneis imposter; Navicula spp.; Nitzschia bicapitata; Nitzschia closterium; Nitzschia longissima; Antarc*; Antarctica; antarcticus; Southern Ocean
• Online Access: https://dx.doi.org/10.1594/pangaea.860296; https://doi.pangaea.de/10.1594/PANGAEA.860296

In the naturally iron-fertilized surface waters of the northern Kerguelen Plateau region, the early spring diatom community composition and contribution to plankton carbon biomass were investigated and compared with the High Nutrient Low Chlorophyll (HNLC) surrounding waters (October-November 2011, KEOPS 2). The large iron-induced blooms were dominated by small diatom species belonging to the genera Chaetoceros (Hyalochaete) and Thalassiosira, which rapidly responded to the onset of favorable light-conditions in the meander of the Polar Front. In comparison, the iron-limited HNLC area was typically characterized by autotrophic nanoeukaryote-dominated communities and by larger and more heavily silicified diatom species (e.g. Fragilariopsis spp.). Our results support the hypothesis that diatoms are valuable vectors of carbon export to depth in naturally iron-fertilized systems of the Southern Ocean. Comparison with the diatom assemblage composition of a sediment trap deployed in the iron-fertilized area ... : Project: KErguelen Ocean and Plateau compared Study 2 (KEOPS2) (http://www.com.univ-mrs.fr/~queguiner/KEOPS_2.html)Seawater samples were collected from 12 L bottle CTD-rosette equipped with a Seabird SBE 911-plus CTD unit. Samples were taken at four to six depths relative to varying Photosynthetically Active Radiation. Diatom counts (live and empty cells) were made following the Utermöhl method (Hasle 1978). Specific diatom C biomass was assessed following the methodology of Cornet-Barthaux et al. (2007). The species-specific contribution to live cell abundance and to C biomass are then calculated from these results. ...