| Processing Steps |
- Parameter or Variable: LATITUDE (measured); Units: decimal degrees; Observation Category: in situ; Sampling Instrument: Furuno GPS Navagation GP-90; Sampling and Analyzing Method: Survey cruise station positions were logged from RV Pelican's differential GPS at the beginning of sampling operations. In addition to the shelfwide survey, YSI casts were made at stations C6C, and C6B on a few dates from a small boat using a Garmin 12XL Personal Navigator. The manufacturer describes the unit as being accurate within 15 meters 95% of the time.; Data Quality Method: GPS manufacturer's accuracy claim is 1-5 meters 95% of the time. Wind, currents and tidal forces may have moved the ship from the beginning position. The Garmin 12XL Personal Navigator manufacturer describes the unit as being accurate within 15 meters 95% of the time..
- Parameter or Variable: LONGITUDE (measured); Units: decimal degrees; Observation Category: in situ; Sampling Instrument: Furuno GPS Navagation GP-90; Sampling and Analyzing Method: Survey cruise station positions were logged from RV Pelican's differential GPS at the beginning of sampling operations. In addition to the shelfwide survey, YSI casts were made at stations C6C, and C6B on a few dates from a small boat using a Garmin 12XL Personal Navigator. The manufacturer describes the unit as being accurate within 15 meters 95% of the time.; Data Quality Method: GPS manufacturer's accuracy claim is 1-5 meters 95% of the time. Wind, currents and tidal forces may have moved the ship from the beginning position. The Garmin 12XL Personal Navigator manufacturer describes the unit as being accurate within 15 meters 95% of the time..
- Parameter or Variable: DISSOLVED OXYGEN (measured); Units: mg/L; Observation Category: in situ; Sampling Instrument: YSI - handheld multi-parameter instrument; Sampling and Analyzing Method: The YSI CTD was attached by chain to a lead weight. The weight was lowered to the bottom by hydrowire. With the weight on the bottom, the sonde was positioned approximately 0.5 meters above the bottom. When the oxygen sensor stabilized, a data record of all the sensor values was stored electronically. During the Shelfwide cruise, the sonde was raised in approximately 0.5-meter increments, after D.O. sensor stabilization on the bottom; data records were stored. After storing data for the few meters closest to the bottom, the sonde was raised to two to three meters from the surface and a data record was saved. The sonde was raised and records stored in approximately 0.5-meter increments until finally a record was stored with the sonde submerged but as close as possible to the surface.; Data Quality Method: The YSI 6820 Oxygen sensor was serviced and calibrated before deployment and maintained in accordance with YSI (http://www.ysi.com/) recommended procedure. The Sonde and Logger are returned to the factory at least annually for inspection and service. Shipboard Winkler titrations during the cruises were used to develop regressions against the YSI data in case it was necessary to correct the oxygen data. YSI oxygen data were corrected for the July Shelfwide cruise using an equation based on the results of the regression..
- Parameter or Variable: CONDUCTIVITY (measured); Units: mS/cm; Observation Category: in situ; Sampling Instrument: YSI - handheld multi-parameter instrument; Sampling and Analyzing Method: The YSI CTD was attached by chain to a lead weight. The weight was lowered to the bottom by hydrowire. With the weight on the bottom, the sonde was positioned approximately 0.5 meters above the bottom. When the oxygen sensor stabilized, a data record of all the sensor values was stored electronically. During the Shelfwide cruise, the sonde was raised in approximately 0.5-meter increments, after D.O. sensor stabilization on the bottom; data records were stored. After storing data for the few meters closest to the bottom, the sonde was raised to two to three meters from the surface and a data record was saved. The sonde was raised and records stored in approximately 0.5-meter increments until finally a record was stored with the sonde submerged but as close as possible to the surface.; Data Quality Method: The YSI 6820 Conductivity sensors were serviced and calibrated before deployment and maintained in accordance with YSI (http://www.ysi.com/) recommended procedure. The Sonde and Logger are returned to the factory at least annually for inspection and service..
- Parameter or Variable: TEMPERATURE [WATER TEMPERATURE] (measured); Units: degrees Celsius; Observation Category: in situ; Sampling Instrument: YSI - handheld multi-parameter instrument; Sampling and Analyzing Method: The YSI CTD was attached by chain to a lead weight. The weight was lowered to the bottom by hydrowire. With the weight on the bottom, the sonde was positioned approximately 0.5 meters above the bottom. When the oxygen sensor stabilized, a data record of all the sensor values was stored electronically. During the Shelfwide cruise, the sonde was raised in approximately 0.5-meter increments, after D.O. sensor stabilization on the bottom; data records were stored. After storing data for the few meters closest to the bottom, the sonde was raised to two to three meters from the surface and a data record was saved. The sonde was raised and records stored in approximately 0.5-meter increments until finally a record was stored with the sonde submerged but as close as possible to the surface.; Data Quality Method: The YSI 6820 temperature sensor was serviced and calibrated before deployment and maintained in accordance with YSI (http://www.ysi.com/) recommended procedure. The Sonde and Logger are returned to the factory at least annually for inspection and service..
- Parameter or Variable: SALINITY (calculated); Units: psu; Observation Category: in situ; Sampling Instrument: YSI - handheld multi-parameter instrument; Sampling and Analyzing Method: The YSI CTD was attached by chain to a lead weight. The weight was lowered to the bottom by hydrowire. With the weight on the bottom, the sonde was positioned approximately 0.5 meters above the bottom. When the oxygen sensor stabilized, a data record of all the sensor values was stored electronically. During the Shelfwide cruise, the sonde was raised in approximately 0.5-meter increments, after D.O. sensor stabilization on the bottom; data records were stored. After storing data for the few meters closest to the bottom, the sonde was raised to two to three meters from the surface and a data record was saved. The sonde was raised and records stored in approximately 0.5-meter increments until finally a record was stored with the sonde submerged but as close as possible to the surface.; Data Quality Method: The YSI 6820 conductivity sensor was serviced and calibrated before deployment and maintained in accordance with YSI (http://www.ysi.com/) recommended procedure. The Sonde and Logger are returned to the factory at least annually for inspection and service. Small adjustments based on correlations with Hanna Salinometer and YSI values were made to YSI salinity data for the July Shelfwide cruise..
- Parameter or Variable: OXYGEN - PERCENT SATURATION (calculated); Units: %; Observation Category: in situ; Sampling Instrument: YSI - handheld multi-parameter instrument; Sampling and Analyzing Method: The YSI CTD was attached by chain to a lead weight. The weight was lowered to the bottom by hydrowire. With the weight on the bottom, the sonde was positioned approximately 0.5 meters above the bottom. When the oxygen sensor stabilized, a data record of all the sensor values was stored electronically. During the Shelfwide cruise, the sonde was raised in approximately 0.5-meter increments, after D.O. sensor stabilization on the bottom; data records were stored. After storing data for the few meters closest to the bottom, the sonde was raised to two to three meters from the surface and a data record was saved. The sonde was raised and records stored in approximately 0.5-meter increments until finally a record was stored with the sonde submerged but as close as possible to the surface.; Data Quality Method: The YSI 6820 Conductivity, Oxygen, and temperature sensors were serviced and calibrated before deployment and maintained in accordance with YSI (http://www.ysi.com/) recommended procedure. The Sonde and Logger are returned to the factory at least annually for inspection and service. Shipboard Winkler titrations during the cruises were used to develop regressions against the YSI data in case it was necessary to correct the oxygen data. YSI oxygen data were corrected for the July Shelfwide cruise using an equation based on the results of the regression..
- Parameter or Variable: INSTRUMENT - DEPTH (measured); Units: meter; Observation Category: in situ; Sampling Instrument: YSI - handheld multi-parameter instrument; Sampling and Analyzing Method: The YSI CTD was attached by chain to a lead weight. The weight was lowered to the bottom by hydrowire. With the weight on the bottom, the sonde was positioned approximately 0.5 meters above the bottom. When the oxygen sensor stabilized, a data record of all the sensor values was stored electronically. During the Shelfwide cruise, the sonde was raised in approximately 0.5-meter increments, after D.O. sensor stabilization on the bottom; data records were stored. After storing data for the few meters closest to the bottom, the sonde was raised to two to three meters from the surface and a data record was saved. The sonde was raised and records stored in approximately 0.5-meter increments until finally a record was stored with the sonde submerged but as close as possible to the surface.; Data Quality Method: The YSI 6820 pressure sensor was serviced and calibrated before deployment and maintained in accordance with YSI (http://www.ysi.com/) recommended procedure. The Sonde and Logger are returned to the factory at least annually for inspection and service..
- Parameter or Variable: AMMONIUM (NH4) (measured); Units: micromole/liter; Observation Category: laboratory analysis; Sampling Instrument: Lachat QuikChem; Sampling and Analyzing Method: Water for nutrient analyses was collected from the surface by twice-rinsed bucket at all stations. Bottom water samples for nutrient analyses were collected in a 5-l bottom tripping Niskin deployed on the YSI hydrowire at all stations. Depth values of "0" indicate a bucket sample collected from the surface of the water. Generally, deepest depths of water samples were from the bottom-tripping Niskin and correspond to the deepest depth recorded from the YSI. Mid water nutrient samples were collected at C6C a using Niskin bottles using corresponding Seabird data, adjusting for the SeaBird pressure sensor being located approximately 0.75 meters below the mid-point of the 5-L Niskin. Ammonium samples were analyzed according to Lachat Instrument's QuikChem method 31-107-06-1-B.; Data Quality Method: Nutrient analyses were conducted using a QuikChem 8000 FIA+ (http://www.lachatinstruments.com). Charlie Milan performed the analyses under the supervision of R. E. Turner, LSU..
- Parameter or Variable: nitrate + nitrite content (concentration) (measured); Units: micromole/liter; Observation Category: laboratory analysis; Sampling Instrument: Lachat QuikChem; Sampling and Analyzing Method: Water for nutrient analyses was collected from the surface by twice-rinsed bucket at all stations. Bottom water samples for nutrient analyses were collected in a 5-l bottom tripping Niskin deployed on the YSI hydrowire at all stations. Depth values of "0" indicate a bucket sample collected from the surface of the water. Generally, deepest depths of water samples were from the bottom-tripping Niskin and correspond to the deepest depth recorded from the YSI. Mid water nutrient samples were collected at C6C a using Niskin bottles using corresponding Seabird data, adjusting for the SeaBird pressure sensor being located approximately 0.75 meters below the mid-point of the 5-L Niskin. Nitrates and Nitrites were determined using Lachat Instrument's Method 31-107-04-1-C.; Data Quality Method: Nutrient analyses were conducted using a QuikChem 8000 FIA+ (http://www.lachatinstruments.com). Charlie Milan performed the analyses under the supervision of R. E. Turner, LSU..
- Parameter or Variable: PHOSPHATE - INORGANIC [phosphate] (measured); Units: micromole/liter; Observation Category: laboratory analysis; Sampling Instrument: Lachat QuikChem; Sampling and Analyzing Method: Water for nutrient analyses was collected from the surface by twice-rinsed bucket at all stations. Bottom water samples for nutrient analyses were collected in a 5-l bottom tripping Niskin deployed on the YSI hydrowire at all stations. Depth values of "0" indicate a bucket sample collected from the surface of the water. Generally, deepest depths of water samples were from the bottom-tripping Niskin and correspond to the deepest depth recorded from the YSI. Mid water nutrient samples were collected at C6C a using Niskin bottles using corresponding Seabird data, adjusting for the SeaBird pressure sensor being located approximately 0.75 meters below the mid-point of the 5-L Niskin. Phosphates are determined by Lachat Instrument's QuikChem Method 31-115-01-1-H.; Data Quality Method: Nutrient analyses were conducted using a QuikChem 8000 FIA+ (http://www.lachatinstruments.com). Charlie Milan performed the analyses under the supervision of R. E. Turner, LSU..
- Parameter or Variable: silicate (measured); Units: micromole/liter; Observation Category: laboratory analysis; Sampling Instrument: Lachat QuikChem; Sampling and Analyzing Method: Water for nutrient analyses was collected from the surface by twice-rinsed bucket at all stations. Bottom water samples for nutrient analyses were collected in a 5-l bottom tripping Niskin deployed on the YSI hydrowire at all stations. Depth values of "0" indicate a bucket sample collected from the surface of the water. Generally, deepest depths of water samples were from the bottom-tripping Niskin and correspond to the deepest depth recorded from the YSI. Mid water nutrient samples were collected at C6C a using Niskin bottles using corresponding Seabird data, adjusting for the SeaBird pressure sensor being located approximately 0.75 meters below the mid-point of the 5-L Niskin. Silicates were measured using Lachat Instrument's Method 31-114-27-1-C.; Data Quality Method: Nutrient analyses were conducted using a QuikChem 8000 FIA+ (http://www.lachatinstruments.com). Charlie Milan performed the analyses under the supervision of R. E. Turner, LSU..
- Parameter or Variable: CHLOROPHYLL - EXTRACTED (measured); Units: microgram/liter; Observation Category: laboratory analysis; Sampling Instrument: Turner digital 10-AU; Sampling and Analyzing Method: Water for chlorophyll analyses was collected from the surface by twice-rinsed bucket at all stations. Bottom water samples for chlorophyll analyses were collected in a 5-l bottom tripping Niskin deployed on the YSI hydrowire at all stations. Depth values of "0" indicate a bucket sample collected from the surface of the water. Generally, deepest depths of water samples were from the bottom-tripping Niskin and correspond to the deepest depth recorded from the YSI. Mid water samples were collected at C6C and C6B, for analysis of chlorophyll a in 5-l Niskin bottles on the SeaBird CTD/rosette system or a messenger triggered 5-l Niskin on the YSI hydrowire. Depths for midwater samples collected using Niskin bottles were taken from corresponding Seabird data, adjusting for the SeaBird pressure sensor being located approximately 0.75 meters below the mid-point of the 5-L Niskin. Water for chlorophyll analysis (10 - 100 ml) was filtered on board ship through GF/F (0.7 micron) filters, which were then fixed in 5 ml of DMSO/90% acetone (40/60) solution, allowed to extract for at least two hours in the dark, then measured pre- and post-acidification on a Turner Model 10 AU fluorometer.; Data Quality Method: The Turner Designs model 10 AU fluorometer was calibrated (7/17/14) for chlorophyll a against a chemical supply house chlorophyll a standard measured on a spectrophotometer. Each time the fluorometer was moved, it was tested with a Turner 10-AU solid standard. Solid standard measurements since the date of calibration, indicated no drift in the fluorescence detector. During cruises, the fluorometer was blanked and calibrated daily in accordance with Turner Designs recommended procedures. Pigment measurements were supervised by Nancy Rabalais and quality controlled by Nancy Rabalais..
- Parameter or Variable: PHAEOPIGMENT CONCENTRATION (measured); Units: microgram/liter; Observation Category: laboratory analysis; Sampling Instrument: Turner digital 10-AU; Sampling and Analyzing Method: Water for chlorophyll analyses was collected from the surface by twice-rinsed bucket at all stations. Bottom water samples for chlorophyll analyses were collected in a 5-l bottom tripping Niskin deployed on the YSI hydrowire at all stations. Depth values of "0" indicate a bucket sample collected from the surface of the water. Generally, deepest depths of water samples were from the bottom-tripping Niskin and correspond to the deepest depth recorded from the YSI. Mid water samples were collected at C6C and C6B, for analysis of chlorophyll a in 5-l Niskin bottles on the SeaBird CTD/rosette system or a messenger triggered 5-l Niskin on the YSI hydrowire. Depths for midwater samples collected using Niskin bottles were taken from corresponding Seabird data, adjusting for the SeaBird pressure sensor being located approximately 0.75 meters below the mid-point of the 5-L Niskin. Water for chlorophyll analysis (10 - 100 ml) was filtered on board ship through GF/F (0.7 micron) filters, which were then fixed in 5 ml of DMSO/90% acetone (40/60) solution, allowed to extract for at least two hours in the dark, then measured pre- and post-acidification on a Turner Model 10 AU fluorometer.; Data Quality Method: The Turner Designs model 10 AU fluorometer was calibrated (7/17/14) for chlorophyll a against a chemical supply house chlorophyll a standard measured on a spectrophotometer. Each time the fluorometer was moved, it was tested with a Turner 10-AU solid standard. Solid standard measurements since the date of calibration, indicated no drift in the fluorescence detector. During cruises, the fluorometer was blanked and calibrated daily in accordance with Turner Designs recommended procedures. Pigment measurements were supervised by Nancy Rabalais and quality controlled by Nancy Rabalais..
- Parameter or Variable: Total PIGMENTS (calculated); Units: microgram/liter; Observation Category: laboratory analysis; Sampling Instrument: Turner digital 10-AU; Sampling and Analyzing Method: Water for chlorophyll analyses was collected from the surface by twice-rinsed bucket at all stations. Bottom water samples for chlorophyll analyses were collected in a 5-l bottom tripping Niskin deployed on the YSI hydrowire at all stations. Depth values of "0" indicate a bucket sample collected from the surface of the water. Generally, deepest depths of water samples were from the bottom-tripping Niskin and correspond to the deepest depth recorded from the YSI. Mid water samples were collected at C6C and C6B, for analysis of chlorophyll a in 5-l Niskin bottles on the SeaBird CTD/rosette system or a messenger triggered 5-l Niskin on the YSI hydrowire. Depths for midwater samples collected using Niskin bottles were taken from corresponding Seabird data, adjusting for the SeaBird pressure sensor being located approximately 0.75 meters below the mid-point of the 5-L Niskin. Water for chlorophyll analysis (10 - 100 ml) was filtered on board ship through GF/F (0.7 micron) filters, which were then fixed in 5 ml of DMSO/90% acetone (40/60) solution, allowed to extract for at least two hours in the dark, then measured pre- and post-acidification on a Turner Model 10 AU fluorometer.; Data Quality Method: The Turner Designs model 10 AU fluorometer was calibrated (7/17/14) for chlorophyll a against a chemical supply house chlorophyll a standard measured on a spectrophotometer. Each time the fluorometer was moved, it was tested with a Turner 10-AU solid standard. Solid standard measurements since the date of calibration, indicated no drift in the fluorescence detector. During cruises, the fluorometer was blanked and calibrated daily in accordance with Turner Designs recommended procedures. Pigment measurements were supervised by Nancy Rabalais and quality controlled by Nancy Rabalais..
- Parameter or Variable: Mean Fo/Fa (calculated); Units: unitless; Observation Category: laboratory analysis; Sampling Instrument: Turner digital 10-AU; Sampling and Analyzing Method: Water for chlorophyll analyses was collected from the surface by twice-rinsed bucket at all stations. Bottom water samples for chlorophyll analyses were collected in a 5-l bottom tripping Niskin deployed on the YSI hydrowire at all stations. Depth values of "0" indicate a bucket sample collected from the surface of the water. Generally, deepest depths of water samples were from the bottom-tripping Niskin and correspond to the deepest depth recorded from the YSI. Mid water samples were collected at C6C and C6B, for analysis of chlorophyll a in 5-l Niskin bottles on the SeaBird CTD/rosette system or a messenger triggered 5-l Niskin on the YSI hydrowire. Depths for midwater samples collected using Niskin bottles were taken from corresponding Seabird data, adjusting for the SeaBird pressure sensor being located approximately 0.75 meters below the mid-point of the 5-L Niskin. Water for chlorophyll analysis (10 - 100 ml) was filtered on board ship through GF/F (0.7 micron) filters, which were then fixed in 5 ml of DMSO/90% acetone (40/60) solution, allowed to extract for at least two hours in the dark, then measured pre- and post-acidification on a Turner Model 10 AU fluorometer.; Data Quality Method: The Turner Designs model 10 AU fluorometer was calibrated (7/17/14) for chlorophyll a against a chemical supply house chlorophyll a standard measured on a spectrophotometer. Each time the fluorometer was moved, it was tested with a Turner 10-AU solid standard. Solid standard measurements since the date of calibration, indicated no drift in the fluorescence detector. During cruises, the fluorometer was blanked and calibrated daily in accordance with Turner Designs recommended procedures. Pigment measurements were supervised by Nancy Rabalais and quality controlled by Nancy Rabalais..
- Parameter or Variable: SALINITY (measured); Units: psu; Observation Category: laboratory analysis; Sampling Instrument: Guildline Instruments Portasal; Sampling and Analyzing Method: Water for salinity analyses was collected from the surface by twice-rinsed bucket at all stations. Bottom water samples for salinity analyses were collected in a 5-l bottom tripping Niskin deployed on the YSI hydrowire at all stations. Depth values of "0" indicate a bucket sample collected from the surface of the water. Generally, deepest depths of water samples were from the bottom-tripping Niskin and correspond to the deepest depth recorded from the YSI. Water was collected in an acid-washed, triple-rinsed 500ml Nalgene jar from a twice-rinsed bucket of surface water. The jar lid was secured tightly to minimize evaporation. Salinity samples were only collected at stations along the C and F transects during the cruise. Salinity samples were analyzed in the lab by a Hanna Instruments Salinometer (Hanna HI2003-01), using methods derived from Hanna protocols (https://hannainst.com).; Data Quality Method: Salinity samples were analyzed in the lab by a Hanna Instruments Salinometer, using methods derived from Hanna protocols (https://hannainst.com). Salinity analyses were conducted by Wendy Morrison under the supervision of Nancy Rabalais. Salinity calibration samples were not collected on the 20-23 August 2015 cruise..
- Parameter or Variable: DISSOLVED OXYGEN (measured); Units: mg/L; Observation Category: laboratory analysis; Sampling Instrument: Mettler Toledo DL28 Titrator; Sampling and Analyzing Method: Water was collected from Niskin Bottle samples using a 300ml glass BOD bottle. Care was taken so that air bubbles were not introduced into the water sample and titration reagents were added immediately to fix the oxygen. Stations and depths were selected as water samples for Winkler analysis based on homogeneity the oxygen profile around that depth, and the need for a distribution of oxygen values across the observed oxygen range. Winkler samples were analyzed on board the R/V Pelican with a Mettler Toledo DL28 Titrator using dissolved oxygen determination methods outlined in A Practical Handbook of Seawater Analysis by Strickland and Parsons, 1977.; Data Quality Method: Winkler samples were analyzed on board the R/V Pelican with a Mettler Toledo DL28 Titrator using dissolved oxygen determination methods outlined in A Practical Handbook of Seawater Analysis by Strickland and Parsons, 1977. Winkler analyses were conducted by Wendy Morrison under the supervision of Nancy Rabalais. Winkler titrations were not used for the 20-23 August 2015 cruise..
- Parameter or Variable: DEPTH - SENSOR (measured); Units: meter; Observation Category: in situ; Sampling Instrument: SBE-9+, Paroscientific Digiquartz(r) pressure sensor; Sampling and Analyzing Method: The SeaBird CTD number of scans to average in the deck unit was set to one. At the beginning of each hydrocast, the entire CTD/Rosette package was soaked while submerged 0.5m to 1.0m below the surface until pump flow and oxygen values observed via the Sea-Bird deck unit indicated the system was operating correctly. Sensor packages are located below the Niskin bottle rosette sampler. In order to minimize the effect of delays in oxygen sensor response time caused by temperature, sensor condition and plumbing configuration, the CTD package was lowered and raised as close to dead slow as possible. The sensor packages were located below the Niskin bottles and rosette. Stations where the structure of the oxygen profile contained dominant features were used in post-processing the oxygen data (AlignCTD). Sea-Bird CTD data were acquired using Seasoft and processed using SBE Data Processing-Win32 software. All scans were processed without averaging or interpolation with a bin size of one scan. In order to compensate for the delay in oxygen sensor response time and improve the alignment between oxygen sensor values and temperature and conductivity sensor values, the Seasoft module ALIGNCTD was used. See Field SeaBird CTD for selection process of which stations were used for alignment. After alignment, the DERIVE function was used to calculate Depth (m), Salinity (psu), Density sigma-t (kg/m3), Oxygen concentration (mg/L), and Oxygen percent saturation (%). Final data were exported as ascii files. A MATLAB program was used to select a water column profile made up of scans from the downcast of discrete 1-meter (or 0.1-m) measurements. The MATLAB program selected scans as follows: 1) Data from Seabird warm up period sitting on the surface were removed; 2) Upcast data were removed; 3) Data scans were selected at 1.0 meter increments through the water column; 3) When DO values changed significantly (> 1.0 mgO2/L) within 1-meter, scans at 0.1-m intervals were selected within that meter; 4) Minimum oxygen and maximum depth scans were selected.; Data Quality Method: The Paroscientific Digiquartz(r) pressure sensor was factory tested and calibrated at Sea-Bird (http://www.seabird.com/) recommended intervals and maintained and serviced by RV Pelican Electronic Technical support staff in accordance with Sea-Bird procedures..
- Parameter or Variable: SONAR ALTIMETER (measured); Units: meter; Observation Category: in situ; Sampling Instrument: Sonar Altimeter, Teledyne Benthos PSA-900; Sampling and Analyzing Method: The SeaBird CTD number of scans to average in the deck unit was set to one. At the beginning of each hydrocast, the entire CTD/Rosette package was soaked while submerged 0.5m to 1.0m below the surface until pump flow and oxygen values observed via the Sea-Bird deck unit indicated the system was operating correctly. Sensor packages are located below the Niskin bottle rosette sampler. In order to minimize the effect of delays in oxygen sensor response time caused by temperature, sensor condition and plumbing configuration, the CTD package was lowered and raised as close to dead slow as possible. The sensor packages were located below the Niskin bottles and rosette. Stations where the structure of the oxygen profile contained dominant features were used in post-processing the oxygen data (AlignCTD). Sea-Bird CTD data were acquired using Seasoft and processed using SBE Data Processing-Win32 software. All scans were processed without averaging or interpolation with a bin size of one scan. In order to compensate for the delay in oxygen sensor response time and improve the alignment between oxygen sensor values and temperature and conductivity sensor values, the Seasoft module ALIGNCTD was used. See Field SeaBird CTD for selection process of which stations were used for alignment. After alignment, the DERIVE function was used to calculate Depth (m), Salinity (psu), Density sigma-t (kg/m3), Oxygen concentration (mg/L), and Oxygen percent saturation (%). Final data were exported as ascii files. A MATLAB program was used to select a water column profile made up of scans from the downcast of discrete 1-meter (or 0.1-m) measurements. The MATLAB program selected scans as follows: 1) Data from Seabird warm up period sitting on the surface were removed; 2) Upcast data were removed; 3) Data scans were selected at 1.0 meter increments through the water column; 3) When DO values changed significantly (> 1.0 mgO2/L) within 1-meter, scans at 0.1-m intervals were selected within that meter; 4) Minimum oxygen and maximum depth scans were selected.; Data Quality Method: The Teledyne Benthos Altimeter PSA-916 sonar altimeter was factory tested and calibrated at manufacturer recommended intervals and maintained and serviced by RV Pelican Electronic Technical support staff. N.B. Near bottom high altimeter values (>6.0 m) were deleted throughout the dataset, because probes were likely within 1 meter of the bottom. Altimeter values were removed from the August cruise due to a sensor issue..
- Parameter or Variable: PHOTOSYNTHETIC ACTIVE RADIATION (PAR) (measured); Units: microEinsteins/meter^2*sec; Observation Category: in situ; Sampling Instrument: Biospherical Instruments QSP-2300; Sampling and Analyzing Method: The SeaBird CTD number of scans to average in the deck unit was set to one. At the beginning of each hydrocast, the entire CTD/Rosette package was soaked while submerged 0.5m to 1.0m below the surface until pump flow and oxygen values observed via the Sea-Bird deck unit indicated the system was operating correctly. Sensor packages are located below the Niskin bottle rosette sampler. In order to minimize the effect of delays in oxygen sensor response time caused by temperature, sensor condition and plumbing configuration, the CTD package was lowered and raised as close to dead slow as possible. The sensor packages were located below the Niskin bottles and rosette. Stations where the structure of the oxygen profile contained dominant features were used in post-processing the oxygen data (AlignCTD). Sea-Bird CTD data were acquired using Seasoft and processed using SBE Data Processing-Win32 software. All scans were processed without averaging or interpolation with a bin size of one scan. In order to compensate for the delay in oxygen sensor response time and improve the alignment between oxygen sensor values and temperature and conductivity sensor values, the Seasoft module ALIGNCTD was used. See Field SeaBird CTD for selection process of which stations were used for alignment. After alignment, the DERIVE function was used to calculate Depth (m), Salinity (psu), Density sigma-t (kg/m3), Oxygen concentration (mg/L), and Oxygen percent saturation (%). Final data were exported as ascii files. A MATLAB program was used to select a water column profile made up of scans from the downcast of discrete 1-meter (or 0.1-m) measurements. The MATLAB program selected scans as follows: 1) Data from Seabird warm up period sitting on the surface were removed; 2) Upcast data were removed; 3) Data scans were selected at 1.0 meter increments through the water column; 3) When DO values changed significantly (> 1.0 mgO2/L) within 1-meter, scans at 0.1-m intervals were selected within that meter; 4) Minimum oxygen and maximum depth scans were selected.; Data Quality Method: The Biospherical Instruments QSP-2300 in water PAR sensor was factory tested and calibrated at manufacturer recommended intervals and maintained and serviced by RV Pelican Electronic Technical support staff. N.B. Operations were conducted 24-hrs a day on both the July Shelfwide and August cruises, and as such, some irradiance values reflect night time values. In order to make this more clear, irradiance values are provided as in-water and surface PAR data as well as the calculated % Irradiance calculated as the percentage of light from the surface observed at that depth in the water column (in-water PAR / surface PAR * 100)..
- Parameter or Variable: LIGHT TRANSMISSION (measured); Units: percent; Observation Category: in situ; Sampling Instrument: WETLabs C-Star 25 cm path length transmissometer; Sampling and Analyzing Method: The SeaBird CTD number of scans to average in the deck unit was set to one. At the beginning of each hydrocast, the entire CTD/Rosette package was soaked while submerged 0.5m to 1.0m below the surface until pump flow and oxygen values observed via the Sea-Bird deck unit indicated the system was operating correctly. Sensor packages are located below the Niskin bottle rosette sampler. In order to minimize the effect of delays in oxygen sensor response time caused by temperature, sensor condition and plumbing configuration, the CTD package was lowered and raised as close to dead slow as possible. The sensor packages were located below the Niskin bottles and rosette. Stations where the structure of the oxygen profile contained dominant features were used in post-processing the oxygen data (AlignCTD). Sea-Bird CTD data were acquired using Seasoft and processed using SBE Data Processing-Win32 software. All scans were processed without averaging or interpolation with a bin size of one scan. In order to compensate for the delay in oxygen sensor response time and improve the alignment between oxygen sensor values and temperature and conductivity sensor values, the Seasoft module ALIGNCTD was used. See Field SeaBird CTD for selection process of which stations were used for alignment. After alignment, the DERIVE function was used to calculate Depth (m), Salinity (psu), Density sigma-t (kg/m3), Oxygen concentration (mg/L), and Oxygen percent saturation (%). Final data were exported as ascii files. A MATLAB program was used to select a water column profile made up of scans from the downcast of discrete 1-meter (or 0.1-m) measurements. The MATLAB program selected scans as follows: 1) Data from Seabird warm up period sitting on the surface were removed; 2) Upcast data were removed; 3) Data scans were selected at 1.0 meter increments through the water column; 3) When DO values changed significantly (> 1.0 mgO2/L) within 1-meter, scans at 0.1-m intervals were selected within that meter; 4) Minimum oxygen and maximum depth scans were selected.; Data Quality Method: WETLabs C-Star 25 cm path length transmissometer was maintained by RV Pelican Electronic Technical support staff in accordance with Wet Labs recommendations. Transmission values of “100” includes those values that exceeded 100 by 0.0098 to 0.3149..
- Parameter or Variable: FLUORESCENCE (measured); Units: microgram/liter; Observation Category: in situ; Sampling Instrument: Chelsea Instruments Aquatraka III; Sampling and Analyzing Method: The SeaBird CTD number of scans to average in the deck unit was set to one. At the beginning of each hydrocast, the entire CTD/Rosette package was soaked while submerged 0.5m to 1.0m below the surface until pump flow and oxygen values observed via the Sea-Bird deck unit indicated the system was operating correctly. Sensor packages are located below the Niskin bottle rosette sampler. In order to minimize the effect of delays in oxygen sensor response time caused by temperature, sensor condition and plumbing configuration, the CTD package was lowered and raised as close to dead slow as possible. The sensor packages were located below the Niskin bottles and rosette. Stations where the structure of the oxygen profile contained dominant features were used in post-processing the oxygen data (AlignCTD). Sea-Bird CTD data were acquired using Seasoft and processed using SBE Data Processing-Win32 software. All scans were processed without averaging or interpolation with a bin size of one scan. In order to compensate for the delay in oxygen sensor response time and improve the alignment between oxygen sensor values and temperature and conductivity sensor values, the Seasoft module ALIGNCTD was used. See Field SeaBird CTD for selection process of which stations were used for alignment. After alignment, the DERIVE function was used to calculate Depth (m), Salinity (psu), Density sigma-t (kg/m3), Oxygen concentration (mg/L), and Oxygen percent saturation (%). Final data were exported as ascii files. A MATLAB program was used to select a water column profile made up of scans from the downcast of discrete 1-meter (or 0.1-m) measurements. The MATLAB program selected scans as follows: 1) Data from Seabird warm up period sitting on the surface were removed; 2) Upcast data were removed; 3) Data scans were selected at 1.0 meter increments through the water column; 3) When DO values changed significantly (> 1.0 mgO2/L) within 1-meter, scans at 0.1-m intervals were selected within that meter; 4) Minimum oxygen and maximum depth scans were selected.; Data Quality Method: The Chelsea Instruments Aquatraka III Chlorophyll a sensor was factory tested and calibrated at recommended intervals and maintained and serviced by RV Pelican Electronic Technical support staff in accordance with Chelsea Instruments procedures. Sporadic fluorescence spikes of close to 1000 were observed and were removed as sensor anomalies, more reasonable but still high fluorescence values were compared with Wet Labs CDOM and were possible 6820 profiles, if found inconsistent, values were removed..
- Parameter or Variable: TEMPERATURE - WATER [WATER TEMPERATURE] (measured); Units: degrees Celsius; Observation Category: in situ; Sampling Instrument: Dual pumped SBE 3 temperature sensor; Sampling and Analyzing Method: The SeaBird CTD number of scans to average in the deck unit was set to one. At the beginning of each hydrocast, the entire CTD/Rosette package was soaked while submerged 0.5m to 1.0m below the surface until pump flow and oxygen values observed via the Sea-Bird deck unit indicated the system was operating correctly. Sensor packages are located below the Niskin bottle rosette sampler. In order to minimize the effect of delays in oxygen sensor response time caused by temperature, sensor condition and plumbing configuration, the CTD package was lowered and raised as close to dead slow as possible. The sensor packages were located below the Niskin bottles and rosette. Stations where the structure of the oxygen profile contained dominant features were used in post-processing the oxygen data (AlignCTD). Sea-Bird CTD data were acquired using Seasoft and processed using SBE Data Processing-Win32 software. All scans were processed without averaging or interpolation with a bin size of one scan. In order to compensate for the delay in oxygen sensor response time and improve the alignment between oxygen sensor values and temperature and conductivity sensor values, the Seasoft module ALIGNCTD was used. See Field SeaBird CTD for selection process of which stations were used for alignment. After alignment, the DERIVE function was used to calculate Depth (m), Salinity (psu), Density sigma-t (kg/m3), Oxygen concentration (mg/L), and Oxygen percent saturation (%). Final data were exported as ascii files. A MATLAB program was used to select a water column profile made up of scans from the downcast of discrete 1-meter (or 0.1-m) measurements. The MATLAB program selected scans as follows: 1) Data from Seabird warm up period sitting on the surface were removed; 2) Upcast data were removed; 3) Data scans were selected at 1.0 meter increments through the water column; 3) When DO values changed significantly (> 1.0 mgO2/L) within 1-meter, scans at 0.1-m intervals were selected within that meter; 4) Minimum oxygen and maximum depth scans were selected.; Data Quality Method: Dual pumped sbe 3 temperature sensors were factory tested and calibrated at Sea-Bird (http://www.seabird.com/) recommended intervals and maintained and serviced by RV Pelican Electronic Technical support staff in accordance with Sea-Bird procedures..
- Parameter or Variable: CONDUCTIVITY (measured); Units: siemens/m; Observation Category: in situ; Sampling Instrument: Dual pumped SBE 4 conductivity sensor; Sampling and Analyzing Method: The SeaBird CTD number of scans to average in the deck unit was set to one. At the beginning of each hydrocast, the entire CTD/Rosette package was soaked while submerged 0.5m to 1.0m below the surface until pump flow and oxygen values observed via the Sea-Bird deck unit indicated the system was operating correctly. Sensor packages are located below the Niskin bottle rosette sampler. In order to minimize the effect of delays in oxygen sensor response time caused by temperature, sensor condition and plumbing configuration, the CTD package was lowered and raised as close to dead slow as possible. The sensor packages were located below the Niskin bottles and rosette. Stations where the structure of the oxygen profile contained dominant features were used in post-processing the oxygen data (AlignCTD). Sea-Bird CTD data were acquired using Seasoft and processed using SBE Data Processing-Win32 software. All scans were processed without averaging or interpolation with a bin size of one scan. In order to compensate for the delay in oxygen sensor response time and improve the alignment between oxygen sensor values and temperature and conductivity sensor values, the Seasoft module ALIGNCTD was used. See Field SeaBird CTD for selection process of which stations were used for alignment. After alignment, the DERIVE function was used to calculate Depth (m), Salinity (psu), Density sigma-t (kg/m3), Oxygen concentration (mg/L), and Oxygen percent saturation (%). Final data were exported as ascii files. A MATLAB program was used to select a water column profile made up of scans from the downcast of discrete 1-meter (or 0.1-m) measurements. The MATLAB program selected scans as follows: 1) Data from Seabird warm up period sitting on the surface were removed; 2) Upcast data were removed; 3) Data scans were selected at 1.0 meter increments through the water column; 3) When DO values changed significantly (> 1.0 mgO2/L) within 1-meter, scans at 0.1-m intervals were selected within that meter; 4) Minimum oxygen and maximum depth scans were selected.; Data Quality Method: Dual pumped SBE 4 conductivity sensors were factory tested and calibrated at Sea-Bird (http://www.seabird.com/) recommended intervals and maintained and serviced by RV Pelican Electronic Technical support staff in accordance with Sea-Bird procedures..
- Parameter or Variable: SALINITY (calculated); Units: psu; Observation Category: in situ; Sampling Instrument: Dual pumped SBE 4 conductivity sensor; Sampling and Analyzing Method: The SeaBird CTD number of scans to average in the deck unit was set to one. At the beginning of each hydrocast, the entire CTD/Rosette package was soaked while submerged 0.5m to 1.0m below the surface until pump flow and oxygen values observed via the Sea-Bird deck unit indicated the system was operating correctly. Sensor packages are located below the Niskin bottle rosette sampler. In order to minimize the effect of delays in oxygen sensor response time caused by temperature, sensor condition and plumbing configuration, the CTD package was lowered and raised as close to dead slow as possible. The sensor packages were located below the Niskin bottles and rosette. Stations where the structure of the oxygen profile contained dominant features were used in post-processing the oxygen data (AlignCTD). Sea-Bird CTD data were acquired using Seasoft and processed using SBE Data Processing-Win32 software. All scans were processed without averaging or interpolation with a bin size of one scan. In order to compensate for the delay in oxygen sensor response time and improve the alignment between oxygen sensor values and temperature and conductivity sensor values, the Seasoft module ALIGNCTD was used. See Field SeaBird CTD for selection process of which stations were used for alignment. After alignment, the DERIVE function was used to calculate Depth (m), Salinity (psu), Density sigma-t (kg/m3), Oxygen concentration (mg/L), and Oxygen percent saturation (%). Final data were exported as ascii files. A MATLAB program was used to select a water column profile made up of scans from the downcast of discrete 1-meter (or 0.1-m) measurements. The MATLAB program selected scans as follows: 1) Data from Seabird warm up period sitting on the surface were removed; 2) Upcast data were removed; 3) Data scans were selected at 1.0 meter increments through the water column; 3) When DO values changed significantly (> 1.0 mgO2/L) within 1-meter, scans at 0.1-m intervals were selected within that meter; 4) Minimum oxygen and maximum depth scans were selected.; Data Quality Method: Dual pumped SBE 4 conductivity sensors were factory tested and calibrated at Sea-Bird (http://www.seabird.com/) recommended intervals and maintained and serviced by RV Pelican Electronic Technical support staff in accordance with Sea-Bird procedures. Small adjustments were made to the July Shelfwide salinity data, based on correlations with Hanna Salinometer and SeaBird values..
- Parameter or Variable: WATER DENSITY (calculated); Units: kilogram/meter^3; Observation Category: in situ; Sampling Instrument: SBE CTD; Sampling and Analyzing Method: The SeaBird CTD number of scans to average in the deck unit was set to one. At the beginning of each hydrocast, the entire CTD/Rosette package was soaked while submerged 0.5m to 1.0m below the surface until pump flow and oxygen values observed via the Sea-Bird deck unit indicated the system was operating correctly. Sensor packages are located below the Niskin bottle rosette sampler. In order to minimize the effect of delays in oxygen sensor response time caused by temperature, sensor condition and plumbing configuration, the CTD package was lowered and raised as close to dead slow as possible. The sensor packages were located below the Niskin bottles and rosette. Stations where the structure of the oxygen profile contained dominant features were used in post-processing the oxygen data (AlignCTD). Sea-Bird CTD data were acquired using Seasoft and processed using SBE Data Processing-Win32 software. All scans were processed without averaging or interpolation with a bin size of one scan. In order to compensate for the delay in oxygen sensor response time and improve the alignment between oxygen sensor values and temperature and conductivity sensor values, the Seasoft module ALIGNCTD was used. See Field SeaBird CTD for selection process of which stations were used for alignment. After alignment, the DERIVE function was used to calculate Depth (m), Salinity (psu), Density sigma-t (kg/m3), Oxygen concentration (mg/L), and Oxygen percent saturation (%). Final data were exported as ascii files. A MATLAB program was used to select a water column profile made up of scans from the downcast of discrete 1-meter (or 0.1-m) measurements. The MATLAB program selected scans as follows: 1) Data from Seabird warm up period sitting on the surface were removed; 2) Upcast data were removed; 3) Data scans were selected at 1.0 meter increments through the water column; 3) When DO values changed significantly (> 1.0 mgO2/L) within 1-meter, scans at 0.1-m intervals were selected within that meter; 4) Minimum oxygen and maximum depth scans were selected.; Data Quality Method: All sensors on the shipboard CTD were maintained by RV Pelican Electronic Technical support staff in accordance with manufacturer recommendations. Small adjustments were made to the July Shelfwide salinity data, based on correlations with Hanna Salinometer and SeaBird values. Density values were calculated using updated salinity data..
- Parameter or Variable: DISSOLVED OXYGEN (measured); Units: mg/L; Observation Category: in situ; Sampling Instrument: Sea-Bird SBE 43 dissolved oxygen sensor; Sampling and Analyzing Method: The SeaBird CTD number of scans to average in the deck unit was set to one. At the beginning of each hydrocast, the entire CTD/Rosette package was soaked while submerged 0.5m to 1.0m below the surface until pump flow and oxygen values observed via the Sea-Bird deck unit indicated the system was operating correctly. Sensor packages are located below the Niskin bottle rosette sampler. In order to minimize the effect of delays in oxygen sensor response time caused by temperature, sensor condition and plumbing configuration, the CTD package was lowered and raised as close to dead slow as possible. The sensor packages were located below the Niskin bottles and rosette. Stations where the structure of the oxygen profile contained dominant features were used in post-processing the oxygen data (AlignCTD). Sea-Bird CTD data were acquired using Seasoft and processed using SBE Data Processing-Win32 software. All scans were processed without averaging or interpolation with a bin size of one scan. In order to compensate for the delay in oxygen sensor response time and improve the alignment between oxygen sensor values and temperature and conductivity sensor values, the Seasoft module ALIGNCTD was used. See Field SeaBird CTD for selection process of which stations were used for alignment. After alignment, the DERIVE function was used to calculate Depth (m), Salinity (psu), Density sigma-t (kg/m3), Oxygen concentration (mg/L), and Oxygen percent saturation (%). Final data were exported as ascii files. A MATLAB program was used to select a water column profile made up of scans from the downcast of discrete 1-meter (or 0.1-m) measurements. The MATLAB program selected scans as follows: 1) Data from Seabird warm up period sitting on the surface were removed; 2) Upcast data were removed; 3) Data scans were selected at 1.0 meter increments through the water column; 3) When DO values changed significantly (> 1.0 mgO2/L) within 1-meter, scans at 0.1-m intervals were selected within that meter; 4) Minimum oxygen and maximum depth scans were selected.; Data Quality Method: Sea-Bird SBE 43 dissolved oxygen sensor were factory tested and calibrated at Sea-Bird (http://www.seabird.com/) recommended intervals and maintained and serviced by RV Pelican Electronic Technical support staff in accordance with Sea-Bird procedures. At the beginning of the shelfwide and August cruises, oxygen sensors were calibrated using the procedures described in SeaBird APPLICATION NOTE NO. 13-1, Rev. D. On the shelfwide, the Winkler Titration oxygen value was determined chemically from replicate samples processed using a Mettler DL21 Titrator (http://www.mt.com/). Shipboard Winkler titrations were performed during the shelfwide cruise to develop regressions against the SeaBird data (in the event it was necessary to correct the oxygen data). SeaBird oxygen data were corrected for the July Shelfwide using an equation based on the results of the regression. Winkler titrations were conducted under the supervision of Nancy Rabalais. SeaBird data post processing was done by Leslie Smith and Wendy Morrison and quality controlled by Nancy Rabalais. During the August cruise, station C6C casts 1-6 Oxygen data presented are from the primary oxygen sensor. All other stations and casts are data from the secondary oxygen sensor..
- Parameter or Variable: OXYGEN - PERCENT SATURATION (calculated); Units: percent; Observation Category: in situ; Sampling Instrument: SBE CTD; Sampling and Analyzing Method: The SeaBird CTD number of scans to average in the deck unit was set to one. At the beginning of each hydrocast, the entire CTD/Rosette package was soaked while submerged 0.5m to 1.0m below the surface until pump flow and oxygen values observed via the Sea-Bird deck unit indicated the system was operating correctly. Sensor packages are located below the Niskin bottle rosette sampler. In order to minimize the effect of delays in oxygen sensor response time caused by temperature, sensor condition and plumbing configuration, the CTD package was lowered and raised as close to dead slow as possible. The sensor packages were located below the Niskin bottles and rosette. Stations where the structure of the oxygen profile contained dominant features were used in post-processing the oxygen data (AlignCTD). Sea-Bird CTD data were acquired using Seasoft and processed using SBE Data Processing-Win32 software. All scans were processed without averaging or interpolation with a bin size of one scan. In order to compensate for the delay in oxygen sensor response time and improve the alignment between oxygen sensor values and temperature and conductivity sensor values, the Seasoft module ALIGNCTD was used. See Field SeaBird CTD for selection process of which stations were used for alignment. After alignment, the DERIVE function was used to calculate Depth (m), Salinity (psu), Density sigma-t (kg/m3), Oxygen concentration (mg/L), and Oxygen percent saturation (%). Final data were exported as ascii files. A MATLAB program was used to select a water column profile made up of scans from the downcast of discrete 1-meter (or 0.1-m) measurements. The MATLAB program selected scans as follows: 1) Data from Seabird warm up period sitting on the surface were removed; 2) Upcast data were removed; 3) Data scans were selected at 1.0 meter increments through the water column; 3) When DO values changed significantly (> 1.0 mgO2/L) within 1-meter, scans at 0.1-m intervals were selected within that meter; 4) Minimum oxygen and maximum depth scans were selected.; Data Quality Method: All sensors on the shipboard CTD were maintained by RV Pelican Electronic Technical support staff in accordance with manufacturer recommendations. At the beginning of the shelfwide and August cruises, oxygen sensors were calibrated using the procedures described in SeaBird APPLICATION NOTE NO. 13-1, Rev. D. On the shelfwide, the Winkler Titration oxygen value was determined chemically from replicate samples processed using a Mettler DL21 Titrator (http://www.mt.com/). Shipboard Winkler titrations were performed during the shelfwide cruise to develop regressions against the SeaBird data (in the event it was necessary to correct the oxygen data). SeaBird oxygen data were corrected for the July Shelfwide using an equation based on the results of the regression. Winkler titrations were conducted under the supervision of Nancy Rabalais. SeaBird data post processing was done by Leslie Smith and Wendy Morrison and quality controlled by Nancy Rabalais. Small adjustments were made to the July Shelfwide salinity data, based on correlations with Hanna Salinometer and SeaBird values. Oxygen percent values were calculated using updated oxygen and salinity data. During the August cruise, station C6C casts 1-6 Oxygen data presented are from the primary oxygen sensor. All other stations and casts are data from the secondary oxygen sensor..
- Parameter or Variable: Time (measured); Units: Zulu; Observation Category: in situ; Sampling Instrument: Multiple Instrument Data Acquisition System (MIDAS); Data Quality Method: The RV Pelican's Multiple Instrument Data Acquisition System (MIDAS) is maintained by the ship's electronic staff..
- Parameter or Variable: DEPTH - BOTTOM (measured); Units: meter; Observation Category: in situ; Sampling Instrument: Odom Echotrac II Fathometer; Sampling and Analyzing Method: During the July shelfwide cruise stations were occupied along 14 generally North-South transects across the Louisiana and Texas coastal shelves. Station depths ranged from 7.20 to 54.00 meters. The objective was to delimit and describe the area of midsummer bottom dissolved oxygen less than 2 (mg/L). Northern end stations of transects were chosen based on the survey vessel's minimum depth limits for each longitude. The northern extent of hypoxia was not reached on transects A’, A, D', F, G, and I. Hypoxic oxygen levels were found in transects A’, A, B, C, D', D, E, F, G, H, I, and J.; Data Quality Method: Station depths were logged from the ship's Odom Echotrac II (http://www.odomhydrographic.com/) fathometer. The Fathometer was calibrated and maintained by RV Pelican Electronic Technical support staff per manufacturer specifications..
- Parameter or Variable: SALINITY - BOTTOM WATER (measured); Units: psu; Observation Category: in situ; Sampling Instrument: Multiple Instrument Data Acquisition System (MIDAS); Data Quality Method: The RV Pelican's Multiple Instrument Data Acquisition System (MIDAS) is maintained by the ship's electronic staff..
- Parameter or Variable: SECCHI DEPTH (measured); Units: meter; Observation Category: in situ; Sampling Instrument: secchi disk; Sampling and Analyzing Method: Secchi disk depths were measured by hand using standard protocol. Secchi disk depths were only measured during daylight operations..
- Parameter or Variable: CHLOROPHYLL - RELATIVE FLUORESCENCE (measured); Units: ug/L; Observation Category: in situ; Sampling Instrument: YSI - handheld multi-parameter instrument; Sampling and Analyzing Method: The YSI CTD was attached by chain to a lead weight. The weight was lowered to the bottom by hydrowire. With the weight on the bottom, the sonde was positioned approximately 0.5 meters above the bottom. When the oxygen sensor stabilized, a data record of all the sensor values was stored electronically. During the Shelfwide cruise, the sonde was raised in approximately 0.5-meter increments, after D.O. sensor stabilization on the bottom; data records were stored. After storing data for the few meters closest to the bottom, the sonde was raised to two to three meters from the surface and a data record was saved. The sonde was raised and records stored in approximately 0.5-meter increments until finally a record was stored with the sonde submerged but as close as possible to the surface.; Data Quality Method: The YSI 6820 Conductivity, pH, Oxygen, and Chlorophyll sensors were serviced and calibrated before deployment and maintained in accordance with YSI (http://www.ysi.com/) recommended procedures. The Sonde and Logger are returned to the factory at least annually for inspection and service. Elevated bottom YSI Chlorophyll data are due to high levels of Phaeopigments in the hypoxic bottom water in most cases, or potentially sediment kicked up from the weight hitting the bottom..
- Parameter or Variable: SURFACE PHOTOSYNTHETIC ACTIVE RADIATION (PAR) (measured); Units: microEinsteins/meter^2*sec; Observation Category: in situ; Sampling Instrument: Biospherical Instruments QSR Surface PAR; Sampling and Analyzing Method: The SeaBird CTD number of scans to average in the deck unit was set to one. At the beginning of each hydrocast, the entire CTD/Rosette package was soaked while submerged 0.5m to 1.0m below the surface until pump flow and oxygen values observed via the Sea-Bird deck unit indicated the system was operating correctly. Sensor packages are located below the Niskin bottle rosette sampler. In order to minimize the effect of delays in oxygen sensor response time caused by temperature, sensor condition and plumbing configuration, the CTD package was lowered and raised as close to dead slow as possible. The sensor packages were located below the Niskin bottles and rosette. Stations where the structure of the oxygen profile contained dominant features were used in post-processing the oxygen data (AlignCTD). Sea-Bird CTD data were acquired using Seasoft and processed using SBE Data Processing-Win32 software. All scans were processed without averaging or interpolation with a bin size of one scan. In order to compensate for the delay in oxygen sensor response time and improve the alignment between oxygen sensor values and temperature and conductivity sensor values, the Seasoft module ALIGNCTD was used. See Field SeaBird CTD for selection process of which stations were used for alignment. After alignment, the DERIVE function was used to calculate Depth (m), Salinity (psu), Density sigma-t (kg/m3), Oxygen concentration (mg/L), and Oxygen percent saturation (%). Final data were exported as ascii files. A MATLAB program was used to select a water column profile made up of scans from the downcast of discrete 1-meter (or 0.1-m) measurements. The MATLAB program selected scans as follows: 1) Data from Seabird warm up period sitting on the surface were removed; 2) Upcast data were removed; 3) Data scans were selected at 1.0 meter increments through the water column; 3) When DO values changed significantly (> 1.0 mgO2/L) within 1-meter, scans at 0.1-m intervals were selected within that meter; 4) Minimum oxygen and maximum depth scans were selected.; Data Quality Method: The Biospherical Instruments QSR Surface PAR sensor was factory tested and calibrated at manufacturer recommended intervals and maintained and serviced by RV Pelican Electronic Technical support staff. N.B. Operations were conducted 24-hrs a day on both the July Shelfwide and August cruises, and as such, some irradiance values reflect night time values. In order to make this more clear, irradiance values are provided as in-water and surface PAR data as well as the calculated % Irradiance calculated as the percentage of light from the surface observed at that depth in the water column (in-water PAR / surface PAR * 100)..
- Parameter or Variable: LIGHT PENETRATION (calculated); Units: %; Observation Category: in situ; Sampling Instrument: Biospherical Instruments QSP-2300 in water PAR and QSR Surface PAR; Sampling and Analyzing Method: The SeaBird CTD number of scans to average in the deck unit was set to one. At the beginning of each hydrocast, the entire CTD/Rosette package was soaked while submerged 0.5m to 1.0m below the surface until pump flow and oxygen values observed via the Sea-Bird deck unit indicated the system was operating correctly. Sensor packages are located below the Niskin bottle rosette sampler. In order to minimize the effect of delays in oxygen sensor response time caused by temperature, sensor condition and plumbing configuration, the CTD package was lowered and raised as close to dead slow as possible. The sensor packages were located below the Niskin bottles and rosette. Stations where the structure of the oxygen profile contained dominant features were used in post-processing the oxygen data (AlignCTD). Sea-Bird CTD data were acquired using Seasoft and processed using SBE Data Processing-Win32 software. All scans were processed without averaging or interpolation with a bin size of one scan. In order to compensate for the delay in oxygen sensor response time and improve the alignment between oxygen sensor values and temperature and conductivity sensor values, the Seasoft module ALIGNCTD was used. See Field SeaBird CTD for selection process of which stations were used for alignment. After alignment, the DERIVE function was used to calculate Depth (m), Salinity (psu), Density sigma-t (kg/m3), Oxygen concentration (mg/L), and Oxygen percent saturation (%). Final data were exported as ascii files. A MATLAB program was used to select a water column profile made up of scans from the downcast of discrete 1-meter (or 0.1-m) measurements. The MATLAB program selected scans as follows: 1) Data from Seabird warm up period sitting on the surface were removed; 2) Upcast data were removed; 3) Data scans were selected at 1.0 meter increments through the water column; 3) When DO values changed significantly (> 1.0 mgO2/L) within 1-meter, scans at 0.1-m intervals were selected within that meter; 4) Minimum oxygen and maximum depth scans were selected.; Data Quality Method: Biospherical Instruments QSP-2300 in water PAR and QSR Surface PAR sensors were factory tested and calibrated at manufacturer recommended intervals and maintained and serviced by RV Pelican Electronic Technical support staff. N.B. Operations were conducted 24-hrs a day on both the July Shelfwide and August cruises, and as such, some irradiance values reflect night time values. In order to make this more clear, irradiance values are provided as in-water and surface PAR data as well as the calculated % Irradiance calculated as the percentage of light from the surface observed at that depth in the water column (in-water PAR / surface PAR * 100)..
- Parameter or Variable: CDOM Fluorescence [Chromophoric Dissolved Organic Matter (CDOM)] (measured); Units: milligram per cubic meter; Observation Category: in situ; Sampling Instrument: WETLabs CDOM fluorometer; Sampling and Analyzing Method: The SeaBird CTD number of scans to average in the deck unit was set to one. At the beginning of each hydrocast, the entire CTD/Rosette package was soaked while submerged 0.5m to 1.0m below the surface until pump flow and oxygen values observed via the Sea-Bird deck unit indicated the system was operating correctly. Sensor packages are located below the Niskin bottle rosette sampler. In order to minimize the effect of delays in oxygen sensor response time caused by temperature, sensor condition and plumbing configuration, the CTD package was lowered and raised as close to dead slow as possible. The sensor packages were located below the Niskin bottles and rosette. Stations where the structure of the oxygen profile contained dominant features were used in post-processing the oxygen data (AlignCTD). Sea-Bird CTD data were acquired using Seasoft and processed using SBE Data Processing-Win32 software. All scans were processed without averaging or interpolation with a bin size of one scan. In order to compensate for the delay in oxygen sensor response time and improve the alignment between oxygen sensor values and temperature and conductivity sensor values, the Seasoft module ALIGNCTD was used. See Field SeaBird CTD for selection process of which stations were used for alignment. After alignment, the DERIVE function was used to calculate Depth (m), Salinity (psu), Density sigma-t (kg/m3), Oxygen concentration (mg/L), and Oxygen percent saturation (%). Final data were exported as ascii files. A MATLAB program was used to select a water column profile made up of scans from the downcast of discrete 1-meter (or 0.1-m) measurements. The MATLAB program selected scans as follows: 1) Data from Seabird warm up period sitting on the surface were removed; 2) Upcast data were removed; 3) Data scans were selected at 1.0 meter increments through the water column; 3) When DO values changed significantly (> 1.0 mgO2/L) within 1-meter, scans at 0.1-m intervals were selected within that meter; 4) Minimum oxygen and maximum depth scans were selected.; Data Quality Method: The WETLabs CDOM fluorometer was maintained by RV Pelican Electronic Technical support staff in accordance with manufacturer recommendations..
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