Methods and Materials  

N96S: Southern Ocean Winter 1996

CLEAN WATER FOR PRODUCTIVITY 

Water for the experiments was collected with dedicated, Teflon-coated Go-Flo bottles lowered on a Kevlar cable and closed with Teflon messengers. The type of sampling system and cleaning of components, as well as bottle handling and filtration, was modeled after the recommendations of FITZWATER et al. (1982). Measurements of chlorophyll and nitrogen were made on samples collected in the upper 115m with the Kevlar cable and on samples collected from 115m to 300m with the rosette sampler on the CTD. 

CHLOROPHYLL

Chlorophyll a and phaeopigments were determined by the fluorometric technique using a Turner Designs Model 10-005 R fluorometer that was calibrated with commercial chlorophyll a (Sigma). Samples for determination of plant pigments were filtered onto 25-mm Whatman GF/F glass fiber filters and extracted in 90% acetone in a freezer for between 24 and 30 hours (VENRICK and HAYWARD, 1984). Other than the modification of the extraction procedure, the method used is the conventional fluorometric procedure of HOLM-HANSEN et al. (1965) and LORENZEN (1966). Additional samples were also filtered onto 1.0 and 5.0 mm pore size Nuclepore membrane filters. 

UNDERWAY MEASUREMENTS 

A mapping system for continuous measurement of fluorescence using a Turner Designs 10-005 and a SeaTech fluorometer, photosynthetically available radiation sensors (PAR), using two sensors: a LiCor 192-SA and a Biospherical QSR-240, location using a Magellan GPS board, and nitrate using a prototype nitrate analyzer based on a Kloehn syringe that was developed at MBARI (SAKAMOTO et al. 1995) and was used throughout the NOAA survey cruises. 

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