Diatom species of the Australian sector of the Southern Ocean

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).