Bongo Nets

The Bongo frames were 60 cm diameter and were fitted with 153 and 335 um Nitex nets.

1995-11-30

Methods & Sampling
PI: Sharon Smith of: University of Miami dataset: Zooplankton displacement volumes from Bongo tows dates: November 30, 1995 to December 26, 1995 location: N: 22.5043 S: 12.0746 W: 57.3059 E: 68.769 project/cruise: Process 7 TN054, Arabian Sea (Early NE Monsoon) ship: R/V Thomas Thompson Sharon L. Smith Rosenstiel School of Marine and Atmospheric Science University of Miami 4600 Rickenbacker Causeway Miami, FL 33149 Arabian Sea Expedition THOMAS G. THOMPSON TTN054 It is important to note that the size ranges in this data set are NOT identical to those reported by Wishner or Roman for other cruises and samples. nd indicates No Data Station 27 has no corresponding standard station number Dry weight measurements were not made on 335 micron samples Station 1: zp_dw_3 is combined with zp_dw_2 Station 1: 4 red crabs removed from 335 micron sample at sea Station 2: 335 micron net had flowmeter failure; therefore volume filtered in the 153 micron net was applied to the 335 micron net Station 19: 335 micron net; shrimp = 2 cc Station 19: 153 micron net; fish = 4 cc Zooplankton displacement volume measurements of Bongo samples collected during Arabian Sea Cruise TN054 (Process Cruise 7). Sharon L. Smith Rosenstiel School of Marine and Atmospheric Science University of Miami 4600 Rickenbacker Causeway Miami, FL 33149 Zooplankton samples were collected in oblique Bongo net tows which covered approximately the upper 200 m of the water column. The Bongo frames were 60 cm diameter and were fitted with 153 and 335 um Nitex nets. A General Oceanics flow meter model 2030R was secured in the net mouth for the determination of volume filtered. The maximum sampling depth of each tow was determined from a Wildlife Computers Mk3e Time Depth Recorder (TDR) attached to the net frame. The Bongo nets were towed beside the ship at approximately 1.5 to 2 knots through the water. Winch speed was generally 30 meters/minute during deployment and 20 meters/minute during recovery. On board the ship, samples from the 153 um net were split in a modified Folsom Splitter which split the sample into four parts consisting of 50%, 20%, 20% and 10%. In general, 10% was used for dry weight measurements, 20% was preserved for collaborating scientists (Prell, McDonough) and 70% was preserved for displacement volume measurements and taxonomic analysis. The portion of each sample for dry weight measurement was poured through nested sieves of 1050, 560, 200 and 64 um mesh. Each size fraction was then placed on a pre-weighed 9 cm Whatman #1 qualitative filter. The filters were stored in glassine envelopes and placed in a drying oven at 55 to 6 degrees C. Near the end of the cruise the dry weight samples were sealed in cracker tins with desiccant for transport to the laboratory where they were later weighed on a Mettler H20 balance. The samples from the 335 um nets were briefly scanned under a Wild M5 dissecting microscope on the ship to assess the dominant zooplankton taxa and then preserved in their entirety in 4% buffered formaldehyde/seawater for laboratory measurement of displacement volume. In the laboratory, displacement volumes were determined following the methods described by Ahlstrom and Thrailkill (1963), and Kane (1982). In general, samples were poured into 500 or 1000 ml graduated cylinders, depending on the volume of plankton present, the volume of plankton and water was measured, then the sample was poured through a 150 um sieve, allowed to drain, and the volume of water measured. The difference between the two volume measurements was the displacement volume. The displacement volume of each sample was divided by the volume filtered by the net (m^3) and the result is reported here in units of cc/m^3. The size specific dry weights from the 9 cm filters are reported in units of mg/m^3. The size ranges are labeled in the data file as zp_dw_1, zp_dw_2, zp_dw_3, zp_dw_4 and zp_dw_T, and correspond to size fractions of 64-200 um, 200-560 um, 560-1050 um, greater than 1050 um and total dry weight which is the sum of the four size fractions. It is important to note that these size ranges are not identical to those reported by Wishner or Roman for other cruises and samples. References Ahlstrom, E. H. and J. R. Thrailkill, Plankton volume loss with time of preservation, Rep. 9, pp. 57-73, Calif. Coop. Oceanic Fish. Invest., La Jolla, 1963. Kane, J., Effect of season and location on the relationship between zooplankton displacement volume and dry weight in the Northwest Atlantic, Fish. Bull., 80, 631-642, 1982.

Processing Description
TTN054: Displacement Volume and Dry Weight

1995-08-18

Methods & Sampling
PI: Sharon Smith of: University of Miami dataset: Zooplankton displacement volumes from Bongo tows dates: November 30, 1995 to December 26, 1995 location: N: 22.5043 S: 12.0746 W: 57.3059 E: 68.769 project/cruise: Process 5 TN050, Arabian Sea (Late SW Monsoon) ship: R/V Thomas Thompson Sharon L. Smith Rosenstiel School of Marine and Atmospheric Science University of Miami 4600 Rickenbacker Causeway Miami, FL 33149 Arabian Sea Expedition THOMAS G. THOMPSON TTN050 nd indicates No Data Stations 28, 29 and 31 have no corresponding Standard Stations Sta 5; net = 153 um; Approximately 20% of sampled spilled in lab, vol_disp corrected accordingly. Sta 15; both nets; Flowmeter failed, therefore vol_net estimated from regressing vol_filt with the time in the water of other Bongo tows with this net. Sta 19; net = 335 um; 1 crab, 7 cc. measured separately. Sta 25; net = 153 um; 1 crab removed from sample at sea, 10 cc. Sta 25; net = 153 um; Flowmeter data for this sample was suspiciously low, therefore the volume filtered for the paired 335 um net was applied here. Sta 27; net = 153 um; 1 crab removed from sample at sea, 40 cc. Sta 28; net = 335 um; Flowmeter data for this sample was suspiciously low, therefore the volume filtered for the paired 153 um net was applied here. Sta 29; net = 153 um; 1 crab removed from sample at sea, 12 cc. Sta 30; net = 153 um; 1 crab removed from sample at sea, 8 cc. Zooplankton displacement volume measurements of Bongo samples collected during Arabian Sea Cruise TN054 (Process Cruise 7). Sharon L. Smith Rosenstiel School of Marine and Atmospheric Science University of Miami 4600 Rickenbacker Causeway Miami, FL 33149 Zooplankton samples were collected in oblique Bongo net tows which covered approximately the upper 200 m of the water column. The Bongo frames were 60 cm diameter and were fitted with 153 and 335 um Nitex nets. A General Oceanics flow meter model 2030R was secured in the net mouth for the determination of volume filtered. The maximum sampling depth of each tow was determined from a Wildlife Computers Mk3e Time Depth Recorder (TDR) attached to the net frame. The Bongo nets were towed beside the ship at approximately 1.5 to 2 knots through the water. Winch speed was generally 30 meters/minute during deployment and 20 meters/minute during recovery. On board the ship, samples from the 153 um net were split in a modified Folsom Splitter which split the sample into four parts consisting of 50%, 20%, 20% and 10%. In general, 10% was used for dry weight measurements, 20% was preserved for collaborating scientists (Prell, McDonough) and 70% was preserved for displacement volume measurements and taxonomic analysis. The portion of each sample for dry weight measurement was poured through nested sieves of 1050, 560, 200 and 64 um mesh. Each size fraction was then placed on a pre-weighed 9 cm Whatman #1 qualitative filter. The filters were stored in glassine envelopes and placed in a drying oven at 55 to 6 degrees C. Near the end of the cruise the dry weight samples were sealed in cracker tins with desiccant for transport to the laboratory where they were later weighed on a Mettler H20 balance. The samples from the 335 um nets were briefly scanned under a Wild M5 dissecting microscope on the ship to assess the dominant zooplankton taxa and then preserved in their entirety in 4% buffered formaldehyde/seawater for laboratory measurement of displacement volume. In the laboratory, displacement volumes were determined following the methods described by Ahlstrom and Thrailkill (1963), and Kane (1982). In general, samples were poured into 500 or 1000 ml graduated cylinders, depending on the volume of plankton present, the volume of plankton and water was measured, then the sample was poured through a 150 um sieve, allowed to drain, and the volume of water measured. The difference between the two volume measurements was the displacement volume. The displacement volume of each sample was divided by the volume filtered by the net (m^3) and the result is reported here in units of cc/m^3. The size specific dry weights from the 9 cm filters are reported in units of mg/m^3. The size ranges are labeled in the data file as zp_dw_1, zp_dw_2, zp_dw_3, zp_dw_4 and zp_dw_T, and correspond to size fractions of 64-200 um, 200-560 um, 560-1050 um, greater than 1050 um and total dry weight which is the sum of the four size fractions. It is important to note that these size ranges are not identical to those reported by Wishner or Roman for other cruises and samples. References Ahlstrom, E. H. and J. R. Thrailkill, Plankton volume loss with time of preservation, Rep. 9, pp. 57-73, Calif. Coop. Oceanic Fish. Invest., La Jolla, 1963. Kane, J., Effect of season and location on the relationship between zooplankton displacement volume and dry weight in the Northwest Atlantic, Fish. Bull., 80, 631-642, 1982.

Processing Description
TTN050: Displacement Volume only