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

Entry ID: ASAC_113

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Summary

Abstract: 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.

Related URL

Link: VIEW PROJECT HOME PAGE

Description: Public information for ASAC project 113

Geographic Coverage

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Spatial coordinates

	N: -68.5	S: -68.58	E: 77.99	W: 77.8

Min Depth: 10 M

Temporal Coverage

Start Date: 1988-02-02

Stop Date: 1989-02-14

Location Keywords

CONTINENT > ANTARCTICA > Davis Station

CONTINENT > ANTARCTICA > Magnetic Island

Science Keywords

CRYOSPHERE > SEA ICE > SEA ICE AGE

OCEANS > OCEAN CHEMISTRY > BIOGEOCHEMICAL CYCLES

ISO Topic Category

BIOTA

GEOSCIENTIFIC INFORMATION

OCEANS

Platform

FIELD SURVEYS

Instrument

GRAB SAMPLERS

ICE AUGERS

Project

EOSDIS > Earth Observing System Data Information System

ESIP > Earth Science Information Partners Program

MEASURES > Making Earth Science Data Records for Use in Research Environments

CWIC > CEOS WGISS Integrated Catalog

Ancillary Keywords

fluxes

oceanic surface fluxes

Data Set Progress

PLANNED

Originating Center

GES DISC

Data Center

Goddard Earth Sciences Data and Information Services Center (formerly Goddard DAAC), Global Change Data Center, Earth Sciences Division, Science and Exploration Directorate, Goddard Space Flight Center, NASA

Data Center URL: http://disc.gsfc.nasa.gov/

Data Center Personnel
Name: GES DISC HELP DESK SUPPORT GROUP Phone: 301-614-5224 Fax: 301-614-5268 Email: gsfc-help-disc at lists.nasa.gov Contact Address: Goddard Earth Sciences Data and Information Services Center Code 610.2 NASA Goddard Space Flight Center City: Greenbelt Province or State: MD Postal Code: 20771 Country: USA