The Biochemistry, Ecology and Organic Geochemistry of Phaeocystis pouchetii communities of Davis Base, Antarctica

This metadata record covers ASAC projects 113, 191 and 625. (ASAC_113, ASAC_191, ASAC_625).

The total lipid, fatty acid, sterol and pigment composition of water column particulates collected near the Australian Antarctic Base, Davis Station, were analysed over five summer seasons (1988-93) using capillary GC, GC-MS, TLC-FID and HPLC. Polar lipids were the dominant lipid class. Maximum lipid concentrations usually occurred in samples collected in December and January and corresponded with increased algal biomass. Both lipid profiles and microscopic observations showed significant variation in algal biomass and community structure in the water column during each season and on an interannual basis. During the period of diatom blooms (predominantly Nitzschia species) the dominant sterol and fatty acid were trans-22-dehydrocholesterol and 20:5w3, accompanied by a high 16:1w7 to 16:0 ratio. Very high polyunsaturated fatty acid and total lipid concentrations were associated with diatom blooms in the area. Bacterial markers increased late in all seasons after the summer algal blooms. Long chain C30 sterols also increased during the latter half of all seasons. Fjord samples collected in the area reflected greater biomass and diversity in algal and bacterial makers than coastal sites. Signature lipids for the alga Phaeocystis pouchetii, thought to be a major alga in Antarctic waters, were identified in field samples over the five summer seasons studied.

Methods

Study site

Davis Base is situated on the Vestfold Hills, Antarctica and incorporates numerous lakes and fjords (Fig. 1). Samples of water column particulate matter were collected during five summer seasons (1988-93), 500 meters off-shore from Magnetic Island, situated 5 km NW of Davis.

Three other sampling areas were situated in the fjords of the Vestfold hills and include two sites in Ellis Fjord, one midway along Ellis Fjord and one near Ellis Fjord mouth and one sample midway along Long Fjord (Fig. 1). These fjords are protected from the marine environment, but are both marine fjords.

Davis Station and Magnetic Island were used for the weekly sample sites. The mouth of Long Fjord, the mouth of Ellis Fjord, midway down Long Fjord, the deep basin in Ellis Fjord, O'Gorman Rocks and Hawker island (ocean side) were used for monthly samples.

Field collection

There was an initial pilot season in 1988-89, which was followed by two more detailed studies in the summers of 1989-90 and 1990-91. Four samples was also analysed from the 1991-92 and five from the 1992-93 summer seasons. During the initial pilot study at Magnetic Island in the 1988-89 summer, three water column particle samples were taken for lipid analyses. The 1989-90 and 1990-91 summer field seasons incorporated weekly sampling of the water column particulates at Magnetic Island. The phytoplankton in the fjords were studied during the summers of 1989-90 and 1990-91. The three sites that were chosen were all sampled three times in each season. Samples were also collected during the 1989-90 and 1990-91 seasons from the Magnetic Island and Fjord site s for pigment analyses. Three and five samples were collected respectively in the 1991-92 and 1992-93 seasons. Samples were also taken for microscopic analyses.

For lipid analyses 30-40 liter water column particulate samples were collected at a depth of 10 m. A Seastar or INFILTREX water sampler was used in situ to filter the water through a 14.2 cm Schleicher and Schuell glass fibre filter over a three to four hour period. All filters used during sampling were preheated in a muffle furnace at 500 degrees C overnight to minimise contamination.

For pigment analyses 2 to 4 litres were filtered through glass fibre filters (4.7 cm GF/F, nominal pore size 0.7 micro meters). The samples were frozen at -20 degrees C until extraction.

Identification info

Alternate title: The Biochemistry, Ecology and Organic Geochemistry of Phaeocystis pouchetii communities of Davis Base, Antarctica

Date (Publication): 2000-07-18

Edition: 1

Originator

Nichols. P. and Skerratt, J.H.

Publisher

Australian Antarctic Data Centre

Principal investigator

NICHOLS, PETER

CSIRO Marine and Atmospheric Research

GPO BOX 252-80

Hobart

Tasmainia

Australia

+61 3 6232 5279

+61 3 6232 5000 (facsimile)

Principal investigator

SKERRATT, JENNIFER HELEN

CSIRO Marine and Atmospheric Research

GPO BOX 1538

Hobart

Tasmania

7001

Australia

+61 3 6232 5279

+61 3 6224 0530 (facsimile)

Collaborator

NICHOLS, PETER

CSIRO Marine and Atmospheric Research

GPO BOX 252-80

Hobart

Tasmainia

Australia

+61 3 6232 5279

+61 3 6232 5000 (facsimile)

Name: CAASM Metadata

Other citation details: Restricted access

Website: https://data.aad.gov.au/metadata/records/ASAC_113

Status: Completed

Custodian

AU/AADC > Australian Antarctic Data Centre, Australia - AADC, DATA OFFICER (DATA CENTER CONTACT)

Australian Antarctic Division

203 Channel Highway

Kingston

Tasmania

7050

Australia

+61 3 6232 3244

+61 3 6232 3351 (facsimile)

Topic category

Biota
Geoscientific information
Oceans

Extent

Description: Temporal Coverage

Temporal extent

TimePeriod: 1988-02-02 1989-02-14

Extent

Description: Temporal Coverage

Temporal extent

TimePeriod: 1989-12-13 1990-01-12

Extent

Description: Temporal Coverage

Temporal extent

TimePeriod: 1990-10-17 1991-02-01

Extent

Description: Temporal Coverage

Temporal extent

TimePeriod: 1992-10-21 1993-01-23

Extent

Description: Vertical Extent - Altitude

Vertical element

Minimum value: 10

Maximum value: 10

Identifier: urn:x-ogc:def:cs:EPSG:6499

Name: Vertical CS. Axis: height (H). Orientation: up. UoM: m.

Identifier: urn:x-ogc:def:axis:EPSG:114

Name: height