Oxygen concentration determinations, upper and lower end, were made prior to the cruise by the LUMCON CTD technician and entered into the SeaSoft configuration file. A correction was made on the CTD oxygen data based on a regression equation developed from Winkler titrations on board ship. Winkler titrations were conducted under the supervision of Nancy Rabalais. The data for the shelfwide summer 1990 hypoxia cruise were corrected according to a regression equation developed from Winkler titrations. Oxygen data were omitted from the top of cast if concentrations indicated that the CTD oxygen probe was not equilibrated due to inadequate "soak" time or too fast a lowering speed. Oxygen data from an entire CTD cast were omitted from the data set, if there were indications that the oxygen probe never equilibrated.
There are numerous oxygen data gaps in the shelfwide 1990 cruise data set. Improper equilibration of the oxygen probe, raising and lowering of the CTD unit in the upper water column prior to the beginning of a cast, and too fast a lowering speed for the CTD unit resulted in a severely reduced oxygen data set. Rather than submit suspect data to the NECOP master database, the principal investigator eliminated those values prior to submission.
Oxygen data are missing at some or all depths at the stations listed below: A2, A3, A4, A5, A6, A7, A'1, A'2, A'3, A1, B1, B2, B4, B6, B8, B9, C10, C3, C5, C6A, C7, C8A, C9A, D1, D2, D4, D5, D6, D7, E1, E2, E2A, E3, E4, E5, E6, F2, F3, F4, F5, G5, G2, G3, G4, H3, I1, I2, I3, I4, I5, I6, I7, J5, K3, K4, K5, H4, J3 and K2.
Fluorometer voltage values were in excess of 10.00 at one or more depths at the stations listed : A4, A'4, A'5, E1 and G2.
S790Nutrient: Nutrient analyses are conducted by Tom Oswald under the supervision of R. E. Turner.
S790Pigment: The Turner Designs model 10 fluorometer was calibrated for chlorophyll a against a chemical supply house chlorophyll a standard measured on a spectrophotometer yearly (or more frequently if needed). During the cruise, the Fluorometer was blanked and calibrated daily in accordance with Turner Designs recommended procedures. Chlorophyll concentrations were supervised and quality controlled by Nancy Rabalais.
N. Rabalais performed an additional procedure in quality-control/quality-assurance by evaluating relationships between the data in S790Hydro, S790Nutrient, S790Pigment and S790Stns.