Diatom species of the Australian sector of the Southern Ocean

Brief description

The collection aims to showcase the range of Southern Ocean diatom species found in the major hydrological provinces of the Australian Sector of the Southern Ocean along the 140 degrees E. The collection includes specimens collected in the Sub-Antarctic Zone (SAZ), Polar Frontal Zone (PFZ) and Antarctic Zone (AZ).

Samples were collected with McLane Parflux time series sediment traps placed at several depths in the SAZ (47 degrees S site), PFZ (54 degrees S site) and AZ and (61 degrees S site) during the decade 1997-2007. The shortest sampling intervals were eight days and corresponded with the austral summer and autumn, whereas the longest interval was 60 days and corresponded with austral winter. Split aliquots were obtained for taxonomic analysis via scanning electron microscopy (SEM). For improved taxonomic imaging, samples were treated with hydrochloric acid and hydrogen peroxide to remove carbonates and organic matter, respectively. A micropipette was used to transfer the suspension of selected samples to a round-glass cover slip following standard decantation method outlined by Barcena and Abrantes (1998). Samples were air-dried and coated with gold for SEM analysis. SEM analysis was carried out using a JEOL 6480LV scanning electron microscope.

Taxonomy

Diatoms include all algae from the Class Bacillariophyceae and follow the standardised taxonomy of World Register of Marine Species (WoRMS).

Order Asterolamprales

Family Asterolampraceae
Asteromphalus hookeri Ehrenberg
Asteromphalus hyalinus Karsten

Order Achnanthales

Family Cocconeidaceae
Cocconeis sp.

Order Bacillariales

Family Bacillariaceae
Fragilariopsis curta (Van Heurck) Hustedt
Fragilariopsis cylindrus (Grunow) Krieger
Fragilariopsis kerguelensis (O'Meara) Hustedt
Fragilariopsis pseudonana (Hasle) Hasle
Fragilariopsis rhombica (O'Meara) Hustedt
Fragilariopsis separanda Hustedt
Nitzschia bicapitata Cleve
Nitzschia kolaczeckii Grunow
Nitzschia sicula (Castracane) Husted var. bicuneata (Grunow) Hasle
Nitzschia sicula (Castracane) Husted var. rostrata Hustedt
Pseudo-nitzschia heimii Manguin
Pseudo-nitzschia lineola (Cleve) Hasle
Pseudo-nitzschia turgiduloides Hasle

Order Chaetocerotanae incertae sedis

Family Chaetoceraceae
Chaetoceros aequatorialis var. antarcticus Cleve
Chaetoceros atlanticus Cleve
Chaetoceros dichaeta Ehrenberg
Chaetoceros peruvianus Brightwell
Chaetoceros sp.

Order Corethrales

Family Corethraceae
Corethron spp.

Order Coscinodiscales

Family Coscinodiscaceae
Stellarima stellaris (Roper) Hasle et Sims

Family Hemidiscaceae
Actinocyclus sp.
Azpeitia tabularis (Grunow) Fryxell et Sims
Hemidiscus cuneiformis Wallich
Roperia tesselata (Roper) Grunow

Order Hemiaulales

Family Hemiaulaceae
Eucampia antarctica (Castracane) Mangin

Order Naviculales

Family Plagiotropidaceae
Tropidoneis group

Family Naviculaceae
Navicula directa (Smith) Ralfs

Family Pleurosigmataceae
Pleurosigma sp.

Order Rhizosoleniales

Family Rhizosoleniaceae
Dactyliosolen antarcticus Castracane
Rhizosolenia antennata f. semispina Sundstrom
Rhizosolenia antennata (Ehrenberg) Brown f. antennata
Rhizosolenia cf. costata Gersonde
Rhizosolenia polydactyla Castracane f. polydactyla
Rhizosolenia simplex Karsten
Proboscia alata (Brightwell) Sundstrom
Proboscia inermis (Castracane) Jordan Ligowski

Order Thalassiosirales

Family Thalassiosiraceae
Porosira pseudodenticulata (Hustedt) Jouse
Thalassiosira ferelineata Hasle et Fryxell
Thalassiosira gracilis (Karsten) Hustedt
Thalassiosira lentiginosa (Janisch) Fryxell
Thalassiosira oestrupii (Ostenfeld) Hasle var. oestrupii Fryxell et Hasle
Thalassiosira oliveriana (O'Meara) Makarova et Nikolaev
Thalassiosira tumida (Janisch) Hasle

Order Thalassionematales

Family Thalassionemataceae
Thalassionema nitzschioides var. lanceolatum Grunow
Thalassiothrix antarctica Schimper ex Karsten


Data available: 73 SEM images of the most abundant diatom species found at the three sampling sites.

Samples were collected by several sediment traps placed at different depths in the Subantarctic Zone (47 degrees S site), Polar Frontal Zone (54 degrees S site) and Antarctic Zone (61 degrees S site) during the decade 1997-2007. The collection site and date for each species image can be found in Table 1 (see the word document in the download file).