(Table 2) Rate of reduction in cell size (apical length) and growth rate for seven Fragilariopsis kerguelensis strains sampled during POLARSTERN cruise ANT-XXI/3

DOI

The planktonic diatom Fragilariopsis kerguelensis plays an important role in the biogeochemical cycles of the Southern Ocean, where remains of its frustules form the largest deposit of biogenic silica anywhere in the world. We assessed the genetic identity of 26 strains, from cells collected at various sites in the Southern Ocean, using three molecular markers, LSU and ITS rDNA and rbcL. The LSU sequences were identical among the tested strains, ITS sequences were highly similar, and only one base pair difference was detected among the rbcL sequences. These results, together with a large number of successful mating experiments demonstrated that the strains belong to a single biological species. We investigated the mating system and life cycle traits of F. kerguelensis. Cell size diminished gradually in clonal strains. Gamete formation only occurred when strains of opposite mating type - within a cell size range of 7-36 µm - were mixed together. Two binucleate gametes were formed in each gametangium and gamete conjugation produced a zygote that had four nuclei and was surrounded by thin siliceous scales. Two out of the four nuclei subsequently degenerated and the zygote expanded to form an auxospore surrounded by a transverse and a longitudinal perizonium. Staining with the fluorochrome PDMPO provided for the first time a clear demonstration that the longitudinal perizonium is formed after auxospore expansion is complete. Initial cells produced within the mature auxospores were 78-101 µm in length. Various authors have shown that the average valve size of F. kerguelensis varies in sediment samples collected in regions and seasons with different primary production regimes and this parameter has thus been proposed as a biological proxy for palaeo-productivity. A better understanding of the life cycle of F. kerguelensis should help the design of future investigations aimed at testing the link between cell size distribution in the natural environment and the role that environmental factors might have in the regulation of population cell size.

The cell size is the average cell size on day 0 and the growth rate is the average of three measurements.

Supplement to: Fuchs, Nike; Scalco, Eleonora; Kooistra, W H C F; Assmy, Philipp; Montresor, Marina (2013): Genetic characterization and life cycle of the diatom Fragilariopsis kerguelensis. European Journal of Phycology, 48(4), 411-426

Identifier
DOI https://doi.org/10.1594/PANGAEA.847739
Related Identifier https://doi.org/10.1080/09670262.2013.849360
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.847739
Provenance
Creator Fuchs, Nike ORCID logo; Scalco, Eleonora; Kooistra, W H C F ORCID logo; Assmy, Philipp; Montresor, Marina ORCID logo
Publisher PANGAEA
Publication Year 2013
Funding Reference German Research Foundation https://doi.org/10.13039/501100001659 Crossref Funder ID 5472008 https://gepris.dfg.de/gepris/projekt/5472008 Priority Programme 1158 Antarctic Research with Comparable Investigations in Arctic Sea Ice Areas
Rights Creative Commons Attribution 3.0 Unported; https://creativecommons.org/licenses/by/3.0/
OpenAccess true
Representation
Language English
Resource Type Supplementary Dataset; Dataset
Format text/tab-separated-values
Size 42 data points
Discipline Earth System Research
Spatial Coverage (2.252W, -49.735S, 19.002E, -49.400N); South Atlantic Ocean
Temporal Coverage Begin 2004-01-30T22:50:00Z
Temporal Coverage End 2004-02-11T18:45:00Z