AUTHOR: Dr. Carin Ashjian
NSF GRANT: 0436131
DATE SET OVERVIEW:
This data set contains mesozooplankton abundance from net tows conducted during the SNACS cruises, August - September, 2005 and 2006 in the Chukchi and Beaufort Seas, off the coast of Barrow, Alaska. Each data set presents abundances of all taxa, including copepodite stages for the copepods,as # per m-3 and includes Station number, date, position (latitude, longitude), and depth for each tow.
Vertically integrated sampling of the water column zooplankton was conducted by using a 1/2-m2 mouth area, 3-m length ring net equipped with 150-um mesh, flow meter, and depth recorder. Wire angle of the tow cable was measured and calculations performed to estimate the payout of wire to ensure the net reached between 1-5m above the bottom. Actual depths were measured with a time-depth recorder attached to the net ring. Samples were preserved in 5% buffered formaldehyde in sea water immediately following collection.
Zooplankton were enumerated at the Atlantic Reference Center, Huntsman Marine Science Center, St. Andrews, New Brunswick under the direction of Dr. Gerhard Pohle. Large animals (e.g., cnidarians, ctenophores, fish larvae, all jellies, amphipods, chaetognaths, appendicularians, decapods, ostracods, pteropods, and other) first were removed from the sample and counted. Subsamples then were obtained using the beaker splitting technique (Van Guelpen et al., 1982) to obtain approximately 300 organisms. All copepods were identified to species and copepodite stages. Other taxa were identified to the lowest taxonomic level possible. Five target copepod taxa were selected: Calanus glacialis, C. hyperboreus, Metridia longa, M. lucens, and Pseudocalanus spp. For the first four species, successive aliquots were enumerated until at least 150 of the target copepod species were encountered or until the entire sample had been examined. For Pseudocalanus spp., successive aliquots were enumerated until at least 50 of the target copepod species were encountered or until the entire sample had been examined.
Van Guelpen, L., D.F. Markle, and D.J. Duggan. 1982. An evaluation of accuracy, precision, and speed of several zooplankton subsampling techniques. J. Cons. Int. Explor. Mer, 40: 226-236