All scientific data collected by the Australian Antarctic program (AAp) are eventually described in the Catalogue of Australian Antarctic and Subantarctic Metadata (CAASM). CAASM can be used to search through AAp data descriptions, and it also provides links to access publicly available datasets, which can either be immediately downloaded or obtained from the Australian Antarctic Data Centre (AADC).
The BROKE-West survey was conducted from 30 degrees E and 80 degrees E between January and March 2006. It consisted of 1 east-west transect at the northernmost limit of the survey between 60 degrees S and 62 degrees S between the 10 and 19 of January, followed by 11 meridional transects separated by 5 degrees of longitude and extending from approximately 62 degrees S to the Antarctic continental shelf between the 19 January and 3 March.
This dataset details research undertaken to determine the identity, composition and abundance of protists in the survey area.
Some explanations for terms used in the dataset are as follows:
1. Group is the taxonomic Phylum, Class and occasionally Order to which the taxa belongs. The abbreviations are:
a. Diatom - Diatomophyceae/Bacillariophyceae. These are subdivided into the taxonomic Orders Centrales (centric) and Pennales (pennate)
b. Chryso - Chrysophyceae
c. Dino - Dinophyceae
d. Eugleno - Euglenophyceae
e. Hapto - Haptophyceae
f. Prasino - Prasinophyceae
g. Silico - Dictyochales (silicoflagellates)
h. Choano - Craspedophyceae /Choanoflagellida
i. Ciliate - Phylum Ciliophora
j. Tintinnid - Phylum Ciliophora , Order Spirotrichea, Class Tintinnida
k. Protozoa - refers to grouped rare taxa belonging to a number of Classes
2. Autotroph/Heterotroph refers to the trophic status of the taxa, indicating whether they are autotrophic (plant) or heterotrophic (animal).
3. CTD Station Number refers to the station at which samples were collected. Type indicates whether the samples were collected at the surface "surf" or at the point at which there was maximum chlorophyll fluorescence detected from the CTD flurometer trace "ChlMax".
The data are all cell concentration numbers.
For more information, see the other metadata records related to ASAC project 40 (ASAC_40), ASAC project 2655 (ASAC_2655) and ASAC project 2679 (ASAC_2679).
Sea water samples for determining the identity, composition and abundance of protists were obtained using 20 l Niskin bottles (General Oceanics) mounted on a CTD rosette at 30 sites in surface waters (3-12 m depth) and 26 sites at the Chl max (11-80 m) over a total of 34 locations during the BROKE-West survey. Samples were preserved with 1% vol:vol Lugol's iodine and stored in glass bottles, in the dark at 4 degrees C until processing for either light microscopy or electron microscopy.
Permanent slides were prepared according to the 2-hydroxypropyl methacrylate (HPMA) (Sigma) method of Crumpton (1981), further modified by Sung-Ho Kang (KORDI, pers. comm.). Each sample was filtered at less than 5 kPa onto a 0.45 micron pore size, 25 mm diameter, GN-6 cellulosic membrane filter (Gelman). The filter was then rinsed by filtering a further 15 ml of MilliQ water, removed from the filtration apparatus and placed face down on a cover glass. A few drops of HPMA were placed on the back of the filter and the sample was then transferred to a 60 degrees C cabinet for 12 to 24 h to clear the filter and polymerise the HPMA. Further drops of HPMA were then placed on the back of the filter, a slide placed on top and the sample again polymerised as above for 6-12 h.
Identification of cryptic species was aided by electron microscopy. One litre samples were fixed with 1% glutaraldehyde and stored at 4 degrees C until processed. Each sample was concentrated over a 47 mm diameter 0.8 microns polycarbonate membrane (Poretics) at a vacuum of less than 50 mm Hg and the concentrate resuspended into the sea water remaining above the filter by gentle agitation. For scanning electron microscopy (SEM) cells were settled onto a polylysine-coated glass coverslips, dehydrated with a graded series of acetone, critical point dried, sputter coated with gold and examined using a JEOL JSM 840 SEM. For transmission microscopy (TEM), approximately 40 microlitre aliquots of concentrate were placed on polylysine treated formvar-coated copper grids (Marchant and Thomas, 1983) and fixed for 60 s with 2% OsO4 vapour. The aliquot was allowed to evaporate and the grid was gently rinsed with distilled water. The grids were either negative-stained with 2% uranyl acetate for 30 sec or shadow-cast with platinum/palladium or chromium and examined with a Phillips CM 100 TEM.
Prepared slides were examined using a Zeiss Axioskop microscope equipped with Nomarski interference optics at 400x magnification. Mean concentrations of each protistan taxa were calculated from the number of cells observed over 20 randomly selected quadrats (Whipple grids) for each sample.
These data are publicly available for download at the provided URL.
This data set conforms to the CCBY Attribution License (http://creativecommons.org/licenses/by/4.0/).
Please follow instructions listed in the citation reference provided at http://data.aad.gov.au/aadc/metadata/citation.cfm?entry_id=BROKE-West_Protists when using these data.