Table of Contents

• Coverage
• Dataset Description
  • Methods & Sampling
  • Data Processing Description
• Data Files
• Parameters
• Instruments
• Deployments
• Project Information
• Program Information
• Funding

Extracted Chlorophyll and Phaeopigment

DMO note: The data reported consists of three replicates per each depth horizon sampled.

PI Responsible: Dian J. Gifford

Samples for water column chlorophyll and phaeopigment were collected and analyzed during the following Vital rates 1995 U.S. GLOBEC Georges Bank process cruises:

• EN259
• EN262
• EN264
• EN266
• EN267B (aka EN267II and EN267 LEG 2)

  Water Collection: Seawater was collected using 10-L teflon-lined Go-flo bottles mounted on the Neil Brown CTD rosette. Water was drained into opaque brown 1-L bottles immediately after collection and refrigerated until processed. Samples were collected onto filters within one hour of water collection. In areas where the water column was well mixed, water was collected from the top, middle and bottom of the water column. When the water column was stratified, water was collected from the top, middles and bottom of the water column as well as around the hydrographic features of interest.

  Sample Processing: Samples were prepared for total, <20 µm, and <5 µm chlorophyll and phaeopigment. Samples for total pigments consisted of bulk seawater. Samples for < 20 µm and < 5 µm pigments were passed gently through clean Nitex meshes of appropriate porosity and the filtrate retained for analysis. Three replicate 50-ml samples of each size fraction were collected onto 25 mm GF/F filters, placed into 5 ml of 90% acetone in a capped test tube, and extracted in the freezer for 24 hours prior to analysis.

  Sample Analysis: The filters were removed from defrosted test tubes with a clean stainless steel spatula, the tube wiped clean with a Kimwipe, and samples read on a Turner Designs Model 10 fluorometer before and after acidification with 10% HCl (Parsons et al., 1984).

  Caveat: In general, pigment concentrations in the <5 µm samples were approximately equal to the <20 µm samples (i.e., there was very little chlorophyll in the 5-20 µm size range: most chlorophyll < 20 µm was also < 5 µm). Because of the difficulty of passing seawater quantitatively through the 5 µm mesh, the <5 µm data are more variable than the Total and < 20 µm data. To avoid confusion, the < 5 µm data are not included in the data files. The data are available, and scientific investigators who need it should contact the PI directly.

  Data Use: The data are available for use by any scientific investigator who wishes to use them. The PI must be consulted prior to publication.

  
  Data Submitted by: 
  
  Dian J. Gifford
  Graduate School of Oceanography
  University of Rhode Island
  Narragansett, RI 02882-1197
  
  voice:   401-874-6690
  fax:     401-874-6240
  e-mail:  gifford@gsosun1.gso.uri.edu
  
  updated: Aug 05. 2005, gfh
  

Seawater was collected using 10-L teflon-lined Go-flo bottles mounted on the Neil Brown CTD rosette. Water was drained into opaque brown 1-L bottles immediately after collection and refrigerated until processed. Samples were collected onto filters within one hour of water collection. In areas where the water column was well mixed, water was collected from the top, middle and bottom of the water column. When the water column was stratified, water was collected from the top, middles and bottom of the water column as well as around the hydrographic features of interest.

Sample Processing: Samples were prepared for total, <20 �m, and <5 �m chlorophyll and phaeopigment. Samples for total pigments consisted of bulk seawater. Samples for < 20 �m and < 5 �m pigments were passed gently through clean Nitex meshes of appropriate porosity and the filtrate retained for analysis. Three replicate 50-ml samples of each size fraction were collected onto 25 mm GF/F filters, placed into 5 ml of 90% acetone in a capped test tube, and extracted in the freezer for 24 hours prior to analysis.

Sample Analysis: The filters were removed from defrosted test tubes with a clean stainless steel spatula, the tube wiped clean with a Kimwipe, and samples read on a Turner Designs Model 10 fluorometer before and after acidification with 10% HCl (Parsons et al., 1984).

Caveat: In general, pigment concentrations in the <5 �m samples were approximately equal to the <20 �m samples (i.e., there was very little chlorophyll in the 5-20 �m size range: most chlorophyll < 20 �m was also < 5 �m). Because of the difficulty of passing seawater quantitatively through the 5 �m mesh, the <5 �m data are more variable than the Total and < 20 �m data. To avoid confusion, the < 5 �m data are not included in the data files. The data are available, and scientific investigators who need it should contact the PI directly.

The U.S. GLOBEC Georges Bank Program is a large multi- disciplinary multi-year oceanographic effort. The proximate goal is to understand the population dynamics of key species on the Bank - Cod, Haddock, and two species of zooplankton (Calanus finmarchicus and Pseudocalanus) - in terms of their coupling to the physical environment and in terms of their predators and prey. The ultimate goal is to be able to predict changes in the distribution and abundance of these species as a result of changes in their physical and biotic environment as well as to anticipate how their populations might respond to climate change.

The effort is substantial, requiring broad-scale surveys of the entire Bank, and process studies which focus both on the links between the target species and their physical environment, and the determination of fundamental aspects of these species' life history (birth rates, growth rates, death rates, etc).

Equally important are the modelling efforts that are ongoing which seek to provide realistic predictions of the flow field and which utilize the life history information to produce an integrated view of the dynamics of the populations.

The U.S. GLOBEC Georges Bank Executive Committee (EXCO) provides program leadership and effective communication with the funding agencies.

U.S. GLOBEC (GLOBal ocean ECosystems dynamics) is a research program organized by oceanographers and fisheries scientists to address the question of how global climate change may affect the abundance and production of animals in the sea.

The U.S. GLOBEC Program currently had major research efforts underway in the Georges Bank / Northwest Atlantic Region, and the Northeast Pacific (with components in the California Current and in the Coastal Gulf of Alaska). U.S. GLOBEC was a major contributor to International GLOBEC efforts in the Southern Ocean and Western Antarctic Peninsula (WAP).