Table of Contents

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

Southern Ocean Biovolume Data from the MOCNESS tows during the Broadscale Cruises, Austral Autumn 2001 and 2002 NB Palmer

This data set is derived from displacement volume measurements and dry weight conversion calculations (see Methods below). The MOCNESS-1 plankton sampler has nine rectangular nets (1m x 1.4 m) with a mesh size of 0.333 mm, which are opened and closed sequentially by commands through conducting cable from the surface (Wiebe et al., 1976).

Cruises:
Nathaniel B. Palmer, April-June 2001 (NBP01-03), 24 tows
Nathaniel B. Palmer, July-Sept. 2001 (NBP01-04), 17 tows
Nathaniel B. Palmer, April-May 2002 (NBP02-02), 24 tows
Nathaniel B. Palmer, July-Sept. 2002 (NBP02-04), 19 tows

Related Datasets:
- Zooplankton Biomass and Abundance from MOCNESS tows using silhouette analysis: NB Palmer, austral fall & winter of 2001 & 2002. Biomass (wet weight) and abundance were determined principally by silhouette digitization of taxa lengths and conversion to equivalent wet weights according to the equations and methods adapted from Davis and Wiebe (1985) and Wiebe et al. (2004). https://www.bco-dmo.org/dataset/2389

- Zooplankton Abundance Based on Taxa and Life Stages or Size Collected during the Broadscale Cruises, Austral Autumn 2001 and 2002, NB Palmer. These abundance values on the same tows were derived by counting and identifying a subset of the zooplankton to the species and life stage for euphausiids and dominant copepods and to taxonomic group with broad size categories for other zooplankton (pteropod, chaetognath, polychaete, etc.). https://www.bco-dmo.org/dataset/2387

This data set is derived from displacement volume measurements and dry weight conversion calculations. The MOCNESS-1 plankton sampler has nine rectangular nets (1m x 1.4 m) with a mesh size of 0.333 mm, which are opened and closed sequentially by commands through conducting cable from the surface (Wiebe et al., 1976).

Methods:
Displacement volume measurement: The entire sample plus liquid was measured in a large graduated cylinder then poured through a sieve into a second cylinder. The difference in volume is the displacement volume.
Detailed instructions:

Measuring Displacement Volume
Supplies: rubber gloves, safety goggles, 2 1-liter graduated cylinders, 2 smaller graduated cylinders (25 to 100 ml), 2 funnels: 1 wide-necked open funnel and 1 small-necked one with mesh attached to the inside or a sieve that fits inside the small-necked funnel, squeeze bottles (water and formalin or other preservative), sieve of mesh size equal to or smaller than that on sampling net.
Put on rubber gloves
Remove jars for 1 net from sample box (may be from one to many jars for a single net sample)
Fill in the data sheet with MOC tow#, date, and net#. jar#
Take first sample to hood. Put on safety goggles.
Remove lid and internal label with long forceps. Get most of zooplankton off by dipping into jar and place label inside lid after checking that internal label agrees with lid label.
Remove large (>5cc) animals (medusae, some fish or shrimp) and measure their displacement volume in the small graduated cylinders:
-Put animal and enough liquid to cover in one small graduated cylinder.-Note this volume on
data sheet.
-Place small sieve in small funnel and set them on top of second empty small grad graduated cylinder.
-Pour animal plus liquid into sieve and let drain.
-Note this volume on data sheet as well as the type of animal.
-Return the specimen to the main sample.
Pour the large sample into the 1-liter graduated cylinder using the open funnel on top (no mesh in funnel). Rinse sparingly the jar, funnel and sides of the graduated cylinder. Diluting the sample with water could cause it to rot. Add a little water with the squeeze bottle to bring the level up to an even line on the graduated cylinder.
Note this volume on the data sheet (sample + liquid)
Place the large funnel containing the sieve or mesh on top of the second, empty graduated cylinder.
Pour the sample into the empty grad. Don't worry about animals stuck to the sides of the first grad. Do not add any liquid to wash sample into the second grad.
Swirl the funnel to remove excess liquid until most of liquid is done dripping (about 1 minute, but varies sample to sample). Carefully drawing the samples toward the center with large forceps is sometimes helpful.
Note this volume on data sheet (liquid vol.)
Rinse the graduated cylinder and the mesh-funnel into the sieve with the hose and return most of the dry sample to the jar using the open funnel.
Use water from faucet with hose to wash the sample on sieve to one side and then use squirt bottle of water (sparingly) or the preservative filled one to rinse the sample from sieve to jar.
Add enough of the filtered formalin to fill the jar, dispose of remainder in appropriate waste container.
- Check the sample's pH and add buffer (sodium borate or borax) if = 8.0.
- Replace cap, swirl if buffer of formalin was added, and rinse outside of jar.
- Rinse everything well after each net sample.

Dry weight calculations:
dry weight = (dvol/(100.139))(1/1.003); [mg/m3]
integrated dry weight = depth interval * dry weight; [mg/m2]
total dry weight for the entire sampled water column = sum of integrated dry weights for all nets for one tow; [mg/m2]

Displacement volume measurement:
Entire sample plus liquid was measured in a large graduated cylinder then poured through a sieve into a second cylinder. The difference in volume is the displacement volume.

Dry weight calculations:
dry weight = (dvol/(10^0.139))^(1/1.003); [mg/m³]
integrated dry weight = depth interval * dry weight; [mg/m²]
total dry weight for the entire sampled water column = sum of integrated dry weights for all nets for one tow; [mg/m²]

This displacement volume data comes from nets with a mesh size of 333 mm.

The fundamental objectives of United States Global Ocean Ecosystems Dynamics (U.S. GLOBEC) Program are dependent upon the cooperation of scientists from several disciplines. Physicists, biologists, and chemists must make use of data collected during U.S. GLOBEC field programs to further our understanding of the interplay of physics, biology, and chemistry. Our objectives require quantitative analysis of interdisciplinary data sets and, therefore, data must be exchanged between researchers. To extract the full scientific value, data must be made available to the scientific community on a timely basis.

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).