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Filter Pad absorption measurements of suspended particulate matter

Federal Geographic Data Committee (FGDC) Metadata:


Identification_Information:
Citation:
Citation_Information:
Originator: Unknown
Publication_Date: Unknown
Title: Filter Pad absorption measurements of suspended particulate matter
Description:
Abstract:
Particulates in the water were concentrated onto 25mm glass fibre filters. Light transmission and reflection through the filters was measured using a spectrophotometer to yield spectral absorption coefficients. Data Acquisition: Water samples were taken from Niskin bottles mounted on the CTD rosette. Two or three depths were selected at each station, using the CTD fluorometer profile to identify the depth of maximum fluorescence and below the fluorescence maximum. One sample was always taken at 10m, provided water was available, as a reference depth for comparisons with satellite data (remote sensing international standard). Water sampling was carried out after other groups, leading to a considerable time delay of between half an hour and 3 hours, during which particulates are likely to have sedimented within the Niskin bottle, and algae photoadapted to the dark. In order to minimise problems of sedimentation, as large a sample as practical was taken. Often so little water remained in the Niskin bottle that the entire remnant was taken. Where less than one litre remained, leftover sample water was taken from the HPLC group. Water samples were filtered through 25mm diameter GF/F filters under a low vacuum (less than 5mmHg), in the dark. Filters were stored in tissue capsules in liquid nitrogen and transported to the lab for analysis after the cruise. Three water samples were filtered through GF/F filters under gravity, with 2 30ml pre-rinses to remove organic substances from the filter, and brought to the laboratory for further filtration through 0.2micron membrane filters. Filters were analysed in batches of 3 to 7, with all depths at each station being analysed within the same batch to ensure comparability. Filters were removed one batch at a time and place on ice in the dark. Once defrosted, the filters were placed upon a drop of filtered seawater in a clean petri dish and returned to cold, dark conditions. One by one, the filters were placed on a clean glass plate and scanned from 200 to 900nm in a spectrophotometer equipped with an integrating sphere. A fresh baseline was taken with each new batch using 2 blank filters from the same batch as the sample filters, soaked in filtered seawater. After scanning, the filters were placed on a filtration manifold, soaked in methanol for between 1 and 2 hours to extract pigments, and rinsed with filtered seawater. They were then scanned again against blanks soaked in methanol and rinsed in filtered seawater. Data Processing: The initial scan of total particulate matter, ap, and the second scan of non-pigmented particles, anp, were corrected for baseline wandering by setting the near-infrared absorption to zero. This technique requires correction for enhanced scattering within the filter, which has been reported to vary with species. One dilution series was carried out at station 118 to allow calculation of the correction (beta-factor). Since it is debatable whether this factor will be applicable to all samples, no correction has been applied to the dataset. Potential users should contact JSchwarz for advice on this matter when using the data quantitatively. Not yet complete: Comparison of the beta-factor calculated for station 118 with the literature values. Comparison of phytoplankton populations from station 118 with those found at other stations to evaluate the applicability of the beta-factor. Dataset Format: Two files: phyto_absorp_brokew.txt and phyto_absorp_brokew_2.txt: covering stations 4 to 90 and 91 to 118, respectively. Note that not every station was sampled. File format: Matlab-readable ascii text with 3 'header' lines: Row 1: col.1=-999, col.2 to end = ctd number Row 2: col.1=-999, col.2 to end = sample depth in metres Row 3: col.1=-999, col.2 to end = 1 for total absorption by particulates, 2 for absorption by non-pigmented particles Row 4 to end: col.1=wavelength in nanometres, col.2 to end = absorption coefficient corresponding to station, depth and type given in rows 1 to 3 of the same column. This work was completed as part of ASAC projects 2655 and 2679 (ASAC_2655, ASAC_2679).
Purpose:
Not Available
Supplemental_Information:
Not Available
Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 20060109
Ending_Date: 20060228
Currentness_Reference:Unknown
Status:
Progress: Complete
Maintenance_and_Update_Frequency: As needed
Spatial_Domain:
Description_of_Geographic_Extent:
Bounding_Coordinates:
West_Bounding_Coordinate: 30.0
East_Bounding_Coordinate: 80.0
North_Bounding_Coordinate: -59.8
South_Bounding_Coordinate: -69.1
Keywords:
Theme:
Theme_Keyword_Thesaurus: GCMD SCIENCE PARAMETERS
Theme_Keyword_Thesaurus: GCMD PLATFORM
Theme_Keyword_Thesaurus: GCMD INSTRUMENT
Theme_Keyword_Thesaurus: ANCILLARY KEYWORDS
Theme_Keyword_Thesaurus: ISO TOPIC CATEGORY
Theme_Keyword_Thesaurus: DATA SET LANGUAGE
Theme_Keyword: EARTH SCIENCE > OCEANS > BATHYMETRY/SEAFLOOR TOPOGRAPHY > WATER DEPTH
Theme_Keyword: EARTH SCIENCE > OCEANS > MARINE SEDIMENTS > SEDIMENTATION
Theme_Keyword: EARTH SCIENCE > OCEANS > OCEAN OPTICS > ABSORPTION
Theme_Keyword: EARTH SCIENCE > OCEANS > OCEAN OPTICS > FLUORESCENCE
Theme_Keyword: EARTH SCIENCE > BIOLOGICAL CLASSIFICATION > PLANTS > MICROALGAE
Theme_Keyword: EARTH SCIENCE > BIOLOGICAL CLASSIFICATION > PLANTS > ALGAE
Theme_Keyword: EARTH SCIENCE > BIOLOGICAL CLASSIFICATION > PLANTS
Theme_Keyword: EARTH SCIENCE > BIOSPHERE > AQUATIC ECOSYSTEMS > PLANKTON > PHYTOPLANKTON
Theme_Keyword: R/V AA > R/V AURORA AUSTRALIS
Theme_Keyword: SHIPS
Theme_Keyword: CTD > CONDUCTIVITY, TEMPERATURE, DEPTH
Theme_Keyword: NISKIN BOTTLES
Theme_Keyword: WATER BOTTLES
Theme_Keyword: Filter Pad Absorption
Theme_Keyword: Particulates
Theme_Keyword: Niskin Water Bottles
Theme_Keyword: Phytoplankton
Theme_Keyword: OCEANS
Theme_Keyword: ENGLISH
Place:
Place_Keyword_Thesaurus: GCMD
Place_Keyword: OCEAN > SOUTHERN OCEAN
Place_Keyword: CONTINENT > ANTARCTICA
Place_Keyword: GEOGRAPHIC REGION > POLAR
Access_Constraints: These data are publicly available from the provided URL.
Use_Constraints:
This data set conforms to the PICCCBY Attribution License (http://creativecommons.org/licenses/by/3.0/). Please follow instructions listed in the citation reference provided at http://data.aad.gov.au/aadc/metadata/citation.cfm?entry_id=BROKE-West_particulates when using these data.
Point_of_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: LESLEY CLEMENTSON
Contact_Person_Primary:
Contact_Person: BRIAN GRIFFITHS (RETIRED)
Contact_Position: TECHNICAL CONTACT
Contact_Position: TECHNICAL CONTACT
Contact_Address:
Address_Type: Mailing and Physical Address
Address: Castray Esplanade
Address: CSIRO Marine and Atmospheric Research
City: Hobart
State_or_Province: Tasmania
Postal_Code: 7000
Country: Australia
Contact_Address:
Address_Type: Mailing and Physical Address
Contact_Voice_Telephone: +61 3 6232 5337
Contact_Electronic_Mail_Address: lesley.clementson@csiro.au
Contact_Electronic_Mail_Address: Brian.Griffiths@csiro.au
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Data_Quality_Information:
Attribute_Accuracy:
Attribute_Accuracy_Report:
All data are usable. However, sampling was not ideal owing to a considerable delay between collection of water samples in the Niskin bottles and subsampling for optical measurements: sedimentation of the sample in the Niskin bottle and photoadaptation by the algae almost certainly occurred to varying extents at each station. Water samples were taken from each CTD cast at between 1 and 3 depths per station.
Logical_Consistency_Report:
Not Available
Completeness_Report:
Not Available
Lineage:
Process_Step:
Process_Description:
Not Available
Process_Date: Unknown
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Spatial_Reference_Information:
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Distribution_Information:
Distributor:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: AU/AADC > Australian Antarctic Data Centre, Australia
Contact_Person: DATA OFFICER AADC
Contact_Position: DATA CENTER CONTACT
Contact_Address:
Address_Type: Mailing and Physical Address
Address: Australian Antarctic Division
Address: 203 Channel Highway
City: Kingston
State_or_Province: Tasmania
Postal_Code: 7050
Country: Australia
Contact_Voice_Telephone: +61 3 6232 3244
Contact_Facsimile_Telephone: +61 3 6232 3351
Contact_Electronic_Mail_Address: metadata@aad.gov.au
Resource_Description: BROKE-West_particulates
Distribution_Liability:
Not Available
Standard_Order_Process:
Digital_Form:
Digital_Transfer_Information:
Format_Name: text
Transfer_Size: 300 kb
Digital_Transfer_Option:
Online_Option:
Computer_Contact_Information:
Network_Address:
Network_Resource_Name:
http://data.aad.gov.au
Access_Instructions:
DATA CENTER URL
Digital_Transfer_Option:
Online_Option:
Computer_Contact_Information:
Network_Address:
Network_Resource_Name:
http://data.aad.gov.au/aadc/portal/download_file.c...
Access_Instructions:
Download point for the data
Digital_Transfer_Option:
Online_Option:
Computer_Contact_Information:
Network_Address:
Network_Resource_Name:
https://secure3.aad.gov.au/proms/public/projects/r...
Access_Instructions:
Public information for ASAC project 2655
Digital_Transfer_Option:
Online_Option:
Computer_Contact_Information:
Network_Address:
Network_Resource_Name:
https://secure3.aad.gov.au/proms/public/projects/r...
Access_Instructions:
Public information for ASAC project 2679
Digital_Transfer_Option:
Online_Option:
Computer_Contact_Information:
Network_Address:
Network_Resource_Name:
http://data.aad.gov.au/aadc/metadata/citation.cfm?...
Access_Instructions:
Citation reference for this metadata record and dataset
Fees: Free
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Metadata_Reference_Information:
Metadata_Date: 20060529
Metadata_Review_Date: 20140911
Metadata_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: JILL SCHWARZ
Contact_Position: INVESTIGATOR
Contact_Position: DIF AUTHOR
Contact_Address:
Address_Type: Mailing and Physical Address
Address: National Institute for Water and Atmosphere Research
Address: 295-301 Evans Bay Parade
City: Greta Point
State_or_Province: Wellington
Postal_Code: 6021
Country: New Zealand
Contact_Facsimile_Telephone: +49 471 4831 1797
Contact_Electronic_Mail_Address: j.schwarz@niwa.co.nz
Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata
Metadata_Standard_Version: FGDC-STD-001-1998
Metadata_Time_Convention: local time
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