File(s) | Type | Description | Action |
---|---|---|---|
zoo_pump.csv (2.72 MB) | Comma Separated Values (.csv) | Primary data file for dataset ID 2332 | Download |
Zooplankton counts (density) from R/V Seward Johnson, R/V Oceanus, and R/V Edwin Link cruises SJ9508, OC303, EL9904, and EL9905 in the Gulf of Maine and Georges Bank from 1995-1999
Principal Investigator: Lewis S. Incze (lincze@usm.maine.edu)
Research Technicians: Ford Dye, Beth Novak, Nicholas Wolff
Methods:
Using a pumping system appended to the CTD unit, measured water volumes (typically 40 liters) were sampled at descrete depths and filtered through 40 micron mesh prior to sorting. A subsample of the filtered sample was used for the zooplankton counts and identification. The size of the subsample varied and depended on the amount of zooplankton present - subsamples were larger when there were fewer animals.
From the subsamples, all zooplankton were counted and identifed. Counts were then converted into number per cubic meter as follows: Number counted / (Subsample size X Amount filtered).
It is worth noting that the frequency of repeated densities is an artifact of the small subsample volumes screened in order to process a large number of samples. The small sample volumes did not give us the ability to resolve small differences in abundance at individual species and stages (e.g., Cal fin Nauplius I). At this level of sorting many counts were reported as zeros, ones, twos or threes. These counts are at the threshold for detection, and the results give the false impression of many identical densities (concentrations). This also shows up in gaps in the life histories as well. For example, a single depth/station might have NI and NIII and NIV stages, but not II or V. As a result, samples were often recombined to give the population characteristics of an integrated water column, or a group of samples. The approach worked well for our research objectives and we are well aware of its limitations. A single station and depth in our data can be deceiving and does not tell the whole story.
Note: Sampling for cruise EL9904, events EL10999.24 and EL111299.6 are intentional replication sites. All sampling was made at same depth level. These stations were used to test the repeatability of methods.
Cruises
Any questions, contact: Lewis S. Incze University of Southern Maine P.O. Box 9300 96 Falmouth Street Portland, ME 04104-9300 Voice: 207 228 8070 Fax: 207 228 8057 Email: (lincze@usm.maine.edu) updated: 23 November 2004; gfh
Incze, L. (2004) Zooplankton counts (density) from R/V Seward Johnson, R/V Oceanus, and R/V Edwin Link cruises SJ9508, OC303, EL9904, and EL9905 in the Gulf of Maine and Georges Bank from 1995-1999 (GB project). Biological and Chemical Oceanography Data Management Office (BCO-DMO). (Version 1) Version Date 2004-11-23 [if applicable, indicate subset used]. doi:10.1575/1912/bco-dmo.2332.1 [access date]
Terms of Use
This dataset is licensed under Creative Commons Attribution 4.0.
If you wish to use this dataset, it is highly recommended that you contact the original principal investigators (PI). Should the relevant PI be unavailable, please contact BCO-DMO (info@bco-dmo.org) for additional guidance. For general guidance please see the BCO-DMO Terms of Use document.