Abstract:

This dataset contains zooplankton data (horizontal and vertical distribution, species composition, and abundance of zooplankton) in the northern Gulf of Mexico obtained aboard the R/V Point Sur (cruise PTS01) from 2015-10-28 to 2015-11-02. Depth-discrete and surface plankton samples were collected during CONCORDE cruise PTS01 (October 28th-November 5th, 2015) using two gear types: a Bedford Institute of Oceanography Net Environmental Sampling System (BIONESS) and a Neuston. The BIONESS (0.25 m2 opening) is a depth-discrete sampler that was fitted with six 333-µm mesh nets and three 202-µm mesh nets and the Neuston (1 x 2 m frame) was fitted with a 505-µm mesh net that sampled at the air-sea interface. Biological samples were collected generally between the 15 and 40 m depth contours between the Chandeleur Islands and the Alabama/Florida border to assess the horizontal and vertical distribution, species composition, and abundance of zooplankton under low freshwater discharge conditions characteristic of the Fall. The dataset contains the date, and latitude and longitude coordinates of the sampling location. The cruise documentation was provided for the R/V Point Sur (cruise PTS01). The cruise was led by chief scientist Dr. Frank Hernandez/Monty Graham.

Suggested Citation:

Culpepper, Carla and Frank Hernandez. 2021. Zooplankton data: horizontal and vertical distribution, species composition, and abundance of zooplankton in the northern Gulf of Mexico, R/V Point Sur cruise, PTS01 from 2015-10-28 to 2015-11-02. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/9ZPWNJY9

Purpose:

Data collection to understand the horizontal and vertical distribution, species composition, and abundance of zooplankton under low freshwater discharge conditions.

Data Parameters and Units:

Zooplankton data tab: Cruise, Sample Date, Station, Gear, Tow Number, Sample ID, Latitude, Longitude, Net, Bin (m), Bin Category, Mesh (um), Swept Volume (m^3), Displacement Volume (mL), Taxa

Methods:

Plankton displacement volume was determined following the methods outlined in the ICES Zooplankton Methodology Manual (2000, Eds. R. Harris, P. Wiebe, J. Lenz, H.-R. Skjoldal and M. Huntley). Samples greater with displacement volumes > 60 mL were further split to generate "sample aliquots", of which one was selected for further processing. The sample aliquot for sorting was poured into a 1000 mL graduated pitcher, and the volume was adjusted to a total of at least 200 mL but no more than 500 mL; this "count volume" was recorded. The aliquot was then stirred and aerated for 1 minute to ensure homogeneity. After aerating, an aliquot using a Stempel Pipet was taken and the "zooplankton aliquot" volume was recorded. The ideal aliquot should be enough to provide a count of at least 200 copepods and 200 of the other organisms combined, but small enough to prevent going over 500 for either. All organisms in the aliquot were counted ("taxon count"). The aliquot was then set aside for quality assurance/quality control by another taxonomist. From every set of 10 sample aliquot counts processed by an individual, one counted aliquot was randomly selected and recounted by someone other than the original taxonomist. Two requirements must be fulfilled to pass the QA/QC process: 1)       Copepod abundances and total non-copepod abundances must be no more than 10% different or no less than 90% the same. 2)       The top 90% of organisms ranked by abundance should be in the same order for the initial sorter and the QA/QC sorter. Exceptions include reversing ranks based on abundances that are within 5% of one another. If the selected aliquot failed, another sample was randomly selected from the same batch and examined. If the second aliquot fails, the entire batch of 10 was re-counted. The total number of each zooplankton taxon for each sample (the column values in the data set for each taxon) was then estimated using the following equation: Total number in sample = Taxon count x (Count Volume / Zooplankton Aliquot) x Sample Aliquot The density (number per cubic meter) of each taxon can then be derived by dividing the column values for each taxon by the swept volume.

Provenance and Historical References:

Carlotti, Francois, Jarl Giske, and F. Werner. 2000. Modeling zooplankton dynamics. InICES Zooplankton Methodology Manual. Ed. by Roger P. Harris, Peter Wiebe, Jurgen Lenz, Mark Huntley, and Hein-Rune Skjoldal. Academic Press, New York. DOI:10.1016/B978-012327645-2/50013-X.

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