Data Introduction
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Database
SAHFOS is unique in having comparable data on the geographical distribution, seasonal cycles and year-to-year changes in abundance of plankton over a large spatial area. There is no other survey in the world with 76 years of marine plankton data.
CPR Data are available in paper form back to 1931 and from
January 1946 onwards in a computerised relational database. The
database contains results from 212,014 samples with 2,542,580
taxonomic abundance entries.
Analysed sample information is entered on to an analysis sheet
which is typed into the computer once the whole route is completed.
These data are then scrutinised by rigorous quality control
methods, before the survey database is incremented. The database
then calculates the accepted mean value for the categories and
applies abundance values. In 2008 a new database for the unique CPR
dataset will be in regular use. The advantage of this new database
is that it streamlines the data input, checking and data extraction
process.
Data - Introduction
The following publications contain information essential
to those using CPR data. The links are to the
National Marine Biological Library "E-prints Facility" where most
CPR and SAHFOS papers are available electronically.
Batten, S.D. and Clarke,
R. and Flinkman, J. and Hays, G. and John, E. and John, A.W.G. and
Jonas, T.D. and Lindley, J.A. and Stevens, D. and Walne, A. (2003)
CPR sampling: the technical background, materials and methods,
and issues of consistency and comparability. Progress in
Oceanography, 58. pp. 193-215. ISSN 0079-6611
Reid, P.C. and Colebrook, J.M. and Matthews, J.B.L. and Aiken, J. (2003) The Continuous Plankton Recorder: concepts and history, from Plankton Indicators to undulating recorders. Progress in Oceanography, 58. pp. 117-173. ISSN 0079-6611
Plankton Analysis
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| 'Eyecount' analysis under the microscope. |
The CPR analysis method has remained unchanged since the 1950s, and underpins the database design (refer to Warner and Hays (1994) for a detailed methodology). Each CPR sample represents 10 nautical miles (approximately 3 cubic metres of water filtered). The analysis procedure comprises 3 stages: (i) phytoplankton, (ii) zooplankton 'traverse' and (iii) zooplankton 'eyecount', all phytoplankton and zooplankton present are identified to species or taxon. Zooplankton 'traverse' and 'eyecount' exact counts are assigned numerical categories. There are 10 numerical categories for phytoplankton and 12 for zooplankton. All analysis is carried out under light microscopes (54x - 450x) and binocular microscopes (17.5x - 140x).