Rabalais, N.
Unknown
Louisiana Hypoxia Surveys 1998
Database
Two sets of CTD data were taken during the 1998 surveys of the Louisiana
continental shelf. Hydrographic data were obtained with the LUMCON
SeaBird 911+ CTD system and a Hydrolab Surveyor 3. Nutrient, pigment,
suspended sediment, surface salinity and station information data were
also acquired.
The physical, biological and chemical data collected are part of a
long-term coastal Louisiana dataset. The goal is to understand physical
and biological processes that contribute to the causes of hypoxia and
use the data to support environmental models for use by resource
managers.
19980113
Unknown
19981215
Unknown
ground condition
As needed
Louisiana coastal waters, Northwestern Gulf of Mexico.
-93.5
-89.4
29.8
28.3
GCMD NASA's Global Change Master Dir. THEME
EARTH SCIENCE > Biosphere > Ecological Dynamics > Biogeochemical
Cycles
EARTH SCIENCE > Biosphere > Ecological Dynamics > Nutrient Cycling
EARTH SCIENCE > Biosphere > Ecological Dynamics > Oxygen Demand
EARTH SCIENCE > Biosphere > Ecological Dynamics > Primary Production
EARTH SCIENCE > Human Dimensions > Environmental Impacts >
Eutrophication
EARTH SCIENCE > Hydrosphere > Water Quality
EARTH SCIENCE > Hydrosphere > Water Quality > Chlorophyll
EARTH SCIENCE > Hydrosphere > Water Quality > Conductivity
EARTH SCIENCE > Hydrosphere > Water Quality > Light Transmission
EARTH SCIENCE > Hydrosphere > Water Quality > Nitrogen Compounds
EARTH SCIENCE > Hydrosphere > Water Quality > Nutrients
EARTH SCIENCE > Hydrosphere > Water Quality > Oxygen
EARTH SCIENCE > Hydrosphere > Water Quality > pH
EARTH SCIENCE > Hydrosphere > Water Quality > Suspended Solids
EARTH SCIENCE > Hydrosphere > Water Quality > Water Temperature
EARTH SCIENCE > Oceans > Coastal Processes
EARTH SCIENCE > Biosphere > Ecological Dynamics > Biogeochemical
Cycles
EARTH SCIENCE > Oceans > Marine Environment Monitoring
EARTH SCIENCE > Oceans > Ocean Chemistry > Ammonia > Ammonium
EARTH SCIENCE > Oceans > Ocean Chemistry > Biogeochemical Cycles
EARTH SCIENCE > Oceans > Ocean Chemistry > Chlorophyll
EARTH SCIENCE > Oceans > Ocean Chemistry > Nitrate
EARTH SCIENCE > Oceans > Ocean Chemistry > Nitrite
EARTH SCIENCE > Oceans > Ocean Chemistry > Nitrogen
EARTH SCIENCE > Oceans > Ocean Chemistry > Nutrients
EARTH SCIENCE > Oceans > Ocean Chemistry > Oxygen
EARTH SCIENCE > Oceans > Ocean Chemistry > pH
EARTH SCIENCE > Oceans > Ocean Chemistry > Phosphate
EARTH SCIENCE > Oceans > Ocean Chemistry > Pigments
EARTH SCIENCE > Oceans > Ocean Chemistry > Silicate
EARTH SCIENCE > Oceans > Ocean Circulation > Fronts
EARTH SCIENCE > Oceans > Ocean Optics > Secchi Depth
EARTH SCIENCE > Oceans > Ocean Temperature
EARTH SCIENCE > Oceans > Salinity/Density
GCMD NASA's Global Change Master Dir. PLACE
Gulf Of Mexico
North Atlantic Ocean
United States Of America
North America
Northern Hemisphere
Sea Surface
None
1. Dataset credit required. 2. Experience with similar datasets has shown
that when data are plotted or used in further analysis, outlying values
may occasionally be discovered. Please report any possible problems with
the data to N. Rabalais.
Nancy N. Rabalais
Louisiana Universities Marine Consortium
mailing address
Louisiana Universities Marine Consortium, 8124 Hwy 56
Chauvin
LA
70344
USA
985 851 2800
985 851 2874
Unknown
N.N., Turner, R.E. and Wiseman, Jr., W.J. Funding: Funds for the research
were provided by the National Oceanic and Atmospheric Administration,
Coastal Ocean Program, Grant Nos. NA86RG0341 and NA960P0112. Funds for
rental of the R/V PELICAN were provided by National Science Foundation
Grant No. OCE-9818985 to Q. Dortch, Louisiana Universities Marine
Consortium, and by NOAA for the July shelfwide cruise.
None
Unclassified
None
Windows 2000, MSAccess 2000
H98Hydrolab: The Hydrolab Surveyor 3 Conductivity, pH and Oxygen sensors
were serviced and calibrated before deployment and maintained in
accordance with Hydrolab (http://www.hydrolab.com/) recommended
procedures. The Sonde and Logger were returned to the factory at least
annually for inspection and service.
December 1998 Transect C Hydrolab CTD conductivity sensor problems were
indicated by many salinity values that were considered too high (greater
than 37ppt).
Seawater samples were collected at the same times and depths the
Hydrolab values were recorded. The seawater samples were later measured
in the laboratory with a PortaSal salinometer. The salinometer values
were used to develop an equation to correct the Hydrolab Salinity
values:
(Hydrolab Salinity - 1.5156)/1.0376 = Corrected Hydrolab Salinity
2180 pairs of Hydrolab spCond-Salinity values (considered good) which
had been acquired on Transect C cruises in 1985 through 1997 were used
to develop a multiple regression model of the form spCond =f(S). The
result of this nonlinear regression exercise was a fourth order
polynomial with a high correlation coefficient (R^2 = 0.99992).
December 1998 Transect C specific conductance was derived as follows.
Derived spCond =
-0.50203+1.92169*(CorrectedHydrolabSalinity)-0.02105*(CorrectedHydrolabSalinity)^2+0.000381377*(CorrectedHydrolabSalinity)^3-0.00000290903*(CorrectedHydrolabSalinity)^4
December 1998 Transect C Density sigma-t values were derived using
methods described in Montgomery, R. B., and Wooster, Warren S.,
"Thermosteric Anomaly and the Analysis of Serial Oceanographic Data',
Deep-Sea Research, Vol. 2, 1954 and values from Knudsen, Martin,
Hydrographical tables, 1901. Formulas available upon request.
December 1998 Transect C Dissolved Oxygen and Percent Oxygen Saturation
values logged by the Hydrolab were not corrected. Values reported for
December 1998 Transect C Dissolved Oxygen and Percent Oxygen Saturation
should be considered suspect.
H98Nutrients: Nutrient analyses were conducted using a Technicon
(http://www.techniconinstruments.com/) autoanalyzer by Tom Oswald under
the supervision of R. E. Turner.
H98Pigments: The Turner Designs model 10 was calibrated for chlorophyll
a against a chemical supply house chlorophyll a standard measured on a
spectrophotometer yearly. During cruises, the fluorometer was blanked
and calibrated daily in accordance with Turner Designs recommended
procedures. Pigment measurements were supervised and quality controlled
by Nancy Rabalais.
H98PortaSal: The samples were analyzed in the lab by Guildline
Instruments PortaSal, using Guildine methods (http://www.guildline.ca/).
Salinity analyses were conducted by Jim Lee under the supervision of R.
E. Turner.
H98Refract: The refractometer was checked with distilled water before
each cruise and re-zeroed when necessary.
H98SeaBird: Sea-Bird SBE 13-01 dissolved oxygen sensors, the
Paroscientific Digiquartz(r) pressure sensor, the SBE 3-01/F temperature
sensors, SBE 5-01 pumps, and the SBE 4-01/0 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. The Sea Tech 500m Fluorometer and Sea Tech 5.0 cm
Transmissometer were factory tested and calibrated at Sea Tech
recommended intervals and maintained and serviced by RV Pelican
Electronic Technical support staff in accordance with Sea Tech
procedures. Note: WET Labs acquired SEA Tech June 1, 1998,
(http://www.wetlabs.com/). The Chelsea Fluorometer was also maintained
by RV Pelican Electronic Technical support staff in accordance with
Chelsea recommended procedures (http://www.chelsea.co.uk/).
Use of a more compact CTD carousel and extension was adopted beginning
with the May 1998 cruise. The SeaBird CTD package was re-oriented from
vertical to horizontal and plumbing was re-configured. The distance from
the center of Niskin sample bottles and the pressure sensor decreased
from 1.0 meter to 0.75 meters.
Before the start of the July shelfwide cruise, oxygen sensors were
calibrated using the procedures described in SeaBird APPLICATION NOTE
NO. 13-1, Rev. D. The Winkler Titration (OXFITW) oxygen value was
determined chemically from replicate samples processed using a Mettler
DL21 Titrator (http://www.mt.com/). Shipboard Winkler titrations during
the cruise were used to develop a regression against CTD data in case it
was necessary to correct the data. The July SeaBird data agreed with the
Winkler values and no correction was necessary.
Winkler titrations and the OXFITW procedure were used to check the
SeaBird oxygen sensors at the beginning of the September - December
cruises.
Winkler titrations were conducted under the supervision of Nancy
Rabalais. Data reductions from the SeaBird were generated by Ben Cole
and quality controlled by Nancy Rabalais.
During monthly surveys conducted in other months, shipboard Winkler
titrations for regressions were not made due to logistical constraints.
Fewer stations were sampled and water columns were often well mixed,
making the considerable effort involved in titrating an inefficient
allocation of resources. A suitable range of data could not be acquired
to develop a strong regression.
For the July SeaBird data, Winkler titrations were used to develop a
regression which was used to correct the SeaBird oxygen data if
necessary. The data for the SeaBird and the Hydrolab compare better for
the shelfwide July cruise.
Jan SeaBird ~ 1mg/L lower than Hydrolab Feb SeaBird ~ 0.8mg/L lower than
Hydrolab Mar SeaBird ~ 0.6-1.0mg/L lower than Hydrolab Apr SeaBird ~
1.5-2.0mg/L too low, Note in log book not to trust May SeaBird ~
0.5-1.0mg/L lower than Hydrolab except C6B higher than Hydrolab Jun
SeaBird C9 no good, delete Jun SeaBird C6B a bit off Jun SeaBird C1 pump
out, no cast Aug SeaBird is similar to Hydrolab Sep SeaBird is similar
to Hydrolab Oct Acadiana Nov SeaBird is off from Hydrolab plus or minus
0.5 Dec SeaBird is similar to Hydrolab
Hydrolab data were derived from a pre- and post-calibrated instrument.
Therefore, there is often disagreement between SeaBird and Hydrolab
oxygen values. It is the opinion of the PI, Nancy Rabalais, that the
Hydrolab data for the monthly cruises are the more reliable data.
H98Stn: Times and locations of operations were acquired from RV
Pelican's Multiple Instrument Data Acquisition System (MIDAS) which was
maintained by the ship's electronic staff. Navigational data were
acquired using either a StarLink Invicta 210S Differential GPS System
with dual output with Gyro interface (http://www.starlinkdgps.com/) or a
Northstar 800x Differential GPS System (http://www.northstarcmc.com).
During April and May 1998 while the Northstar was being repaired a
Garmin GPS 45 with GBR 21 was used. Station depths were logged from the
ship's Odom Echotrac II (http://www.odomhydrographic.com/) fathometer.
The Secchi disk depths were measured by hand using standard protocol.
During the October cruise on the RV Acadiana, position data were logged
from the ship's NorthStar 800 Loran C. Station depths were logged from
Acadiana's fathometer.
H98Midas: Suspended sediment concentrations were supervised by Ben Cole
or Nancy Rabalais and quality controlled by Nancy Rabalais. Times and
locations of operations were acquired from the GPS component of the
ship's MIDAS system (when available).
N. Rabalais performed an additional procedure in
quality-control/quality-assurance by evaluating relationships between
the data in H98Hydrolab, H98Midas, H98Nutrients, H98Pigments,
H98PortaSal, H98Refract, and H98Stn.
Table H98SeaBird lists Sea Tech fluorometer voltage values (FlS) of 30 for
one or more depths at eleven stations in 1998. A value of 30 indicates
that fluorescence was high enough to maximize the sensor.
Table H98SeaBird percent light transmission (Xmiss) values exceeded 100
percent at six stations: 19980414 station C9, 19980512 stations C9 and
C6B, 19980610 station C6BN, C9N and C9.
On 19980113, the 5.0 meter Niskin sample at station C1 was muddy. Nutrient
and Pigment samples were considered compromised and were deleted.
SeaBird Dissolved oxygen (OxMg/L) and percent oxygen saturation data
acquired 19980610 at station C9 were deleted because the data were
considered unreliable.
During the July shelfwide 1998 survey the SeaBird CTD package was
configured with a single fluorometer. No Chelsea Fluorometer (FlC) data
were collected during the July cruise.
Suspended sediment values (SuspSed) that did not meet quality control
criteria were deleted.
The navigation component of the ship's MIDAS system was not always
functional. thirty-two suspended sediment latitude and longitude values
(SS-Lat and SS-Lon) are missing from table H98Midas. The station latitude
and longitude (Lat and Lon) values reported in table H98stn were within
0.3 nautical miles of the suspended sediment sample location.
All station positions, except those acquired during the October cruise
on RV Acadiana, were logged from RV Pelican's differential GPS at the
beginning of sampling operations. GPS manufacturer's accuracy claim is
1-5 meters 95% of the time. Wind, currents and tidal forces may move
the ship from the beginning position.
Station positions acquired during the October cruise on RV Acadiana
were logged from the ship's NorthStar 800 LORANC. The manufacturer
describes the accuracy to be within 30 meters 90% of the time.
On the following dates hydrocasts were made from a small boat tied to
the oilfield platform at station C6B: 19980402, 19980420, 19980619,
19980716, 19980811 and 19981012.
Field SeaBird
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.
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 as close to dead slow as
possible. The sensor packages were located below the Niskin bottles
and rosette.
At stations where the watch chief deemed the structure of the oxygen
profile contained features useful in post-processing the oxygen data
(AlignCTD), the CTD package was raised at the same speed it was
lowered. At all other stations, the upcast is rapid in order to save
time.
Field Hydrolab C Transect
Deployment: The Hydrolab 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 Hydrolab sonde was positioned just above the bottom.
When the oxygen sensor stabilized, a data record of all the sensor
values was stored electronically. The sonde was raised in
approximately 1.0-meter increments, after D.O. sensor stabilization,
data records were stored. When the Hydrolab was raised a depth of two
to three meters from the surface, 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.
Field Hydrolab shelfwide
Deployment: Due to limitations of time, mid-water depths were
generally not sampled with the Hydrolab CTD during the shelfwide
cruise.
The Hydrolab 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 Hydrolab sonde was positioned just above the bottom. When the
oxygen sensor stabilized, a data record of all the sensor values was
stored electronically. The sonde was raised in approximately 0.5-meter
increments, after D.O. sensor stabilization, data records were stored.
After storing data for the few meters closest to the bottom, the
Hydrolab 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.
Field Pigment
Water for chlorophyll analysis (30 - 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 fluorometer.
Field PortaSal
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.
Field Station Locations
C transect lies South and East of Terrebonne Bay. Nine cross-shelf
stations on C transect were sampled monthly. Additional water-column
hydrology measurements were made at station C6B when other research
missions provided opportunities at that location.
During the July shelfwide cruise, stations were occupied along 13
generally North-South transects across the Louisiana coastal shelf.
Station depths ranged from 5.3 to 68.3 meters. The objective was to
delimit and describe the area of midsummer bottom dissolved oxygen
less than 2 (mg/L). Due to limitations of equipment, time and funding,
this was not always possible. 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 four
transects: A', A, C and F. Optimally, one or two stations south of the
southern most station with bottom dissolved oxygen less than 2 (mg/L)
were sampled. The limit of hypoxia on the southern ends of all
transects was reached. The limit of hypoxia was reached at all
stations on the western end of the survey. The limit of hypoxia was
only reached at station A'6 on the eastern end of the survey. Bottom
waters at stations A'1, A'2, A'3 A'4 and A'5 were hypoxic.
Field Nutrient
Care was taken that the collector's hands were clean and avoided
touching the sample water. Gloves were worn when three replicate
sample vials and caps were triple rinsed with sample before vial
filling and closing. Samples were not filtered. The sample vials were
frozen for later analysis in the laboratory.
Field suspended sediments
Water (approximately 300 to 1000 ml) collected for suspended sediment
samples was filtered on board ship through pre-weighed GF/F filters,
rinsed with distilled water. The filters were placed in Petri dishes
and frozen for later analysis.
Field water samples
Water for chlorophyll, nutrient analyses and PortaSal salinity was
collected from the surface by twice-rinsed bucket, from mid-water in
5-l Niskin bottles on the Seabird CTD/rosette system and from bottom
in a 5-l bottom tripping Niskin deployed on the Hydrolab hydrowire.
Depth values of 0 indicate a bucket sample collected from the surface
of the water. Deepest depths of water samples were from the
bottom-tripping Niskin and correspond to the deepest depth recorded
from the Hydrolab. Other depths indicate the p-sensor reading for 5-l
Niskin bottles on the Seabird rosette. The Seabird p-sensor was
located approximately 1 meter below the mid-point of the 5-l Niskin.
Water for Suspended Sediment samples was collected by tapping into
discharge of the shipâ€(tm)s seawater flow through system MIDAS. MIDAS
intake was 2 -3 meters below the surface. The watch chief observed
MIDAS navigational data, when distance to station was 0.3 miles, a
triple-rinsed jar (1000ml) was collected from the silicon MIDAS
discharge tube in the ship's bottle lab. Finally, collection time was
logged.
Lab SPM
Suspended sediment filters were dried at 40 - 60 degrees centigrade
for 24 hours. Filters were weighed. Total suspended sediments were
derived from volume filtered, pre-weight and post weight values.
Lab Nutrient
Nitrogen and phosphorus are analyzed according to methods described in
EPA publication EPA 600/4-79-020 (1979), method 350.1 for ammonia-N,
method 353.2 for nitrate/nitrite-N, and method 365.1 for phosphate-P.
Silicate is analyzed according to Technicon Industrial method 186-72
W/B (1977).
Lab SeaBird
Sea-Bird CTD data were acquired using Seasoft version 4.225 in all
months. Data were post processed using Seasoft version 4.3 January
through March. Data for other months were post processed with Seasoft
version 4.225. All scans were processed without averaging or
interpolation with a bin size of one scan. In order to improve
alignment between oxygen sensor values and other CTD sensor values,
the Seasoft module ALIGNCTD was used, when possible, to determine
which advance best compensated for the delay in oxygen sensor response
time.
When Seabird data were post-processed, dissolved oxygen was advanced
relative to temperature and conductivity values as follows: January
+3.75 seconds; February, March and August +4.0 seconds; July +4.055
seconds; April, September, November and December +4.25 seconds; May
5.5 seconds; and June +6 seconds.
Data values reported are from downcasts. Downcast scans selected for
each CTD station were chosen to illustrate: 1) data values as near to
the surface as possible, 2) data values at whole meter increments, and
3) data values as close to the bottom as the CTD was lowered. In
certain cases where data values of a parameter changed significantly
between whole meter increments, 0.1- or 0.2-meter scans were selected.
Unknown
Unknown
Unknown
Vector
Point
198
0.0001
0.0001
Degrees and decimal minutes
WGS84
WGS84
6378137
298.257223563
H98Hydrolab
The table lists Hydrolab CTD station identification number, record
date, station name, record time, record depth, dissolved oxygen,
temperature, specific conductance, salinity, pH, percent oxygen
saturation and density sigma-t. There are 2685 records.
None.
Date
Date when Hydrolab record was saved. (Date can be different for
suspended sediment, Hydrolab CTD cast and SeaBird CTD cast at same
station). Station A1 0.3m and 1.5m records are dated 19980722. All
other station A1 records are dated 19980721.
Producer defined
19980113
19981215
19980113
19981215
Density
Density sigma-t
Producer defined
1.23
26.06
Density sigma-t
19980113
19981215
Depth
Depth of Hydrolab pressure sensor
Producer Defined
0.1
68.3
Meters
19980113
19981215
DO
Dissolved oxygen
Producer defined
0.05
11.59
mg/L
19980113
19981215
DOPctSat
Oxygen percent saturation
Producer defined
0.7
172.9
Percent
19980113
19981215
pH
pH
Producer defined
7.33
8.42
pH units
19980113
19981215
Salin
Salinity
Producer defined
7.3
36.8
psu
19980113
19981215
SpCond
Specific conductance
Producer defined
12.79
55.3
mS/cm
19980113
19981215
Sta
Station name of location sampled
Producer defined
Character field
19980113
19981215
StnID
Station identification number
Producer defined
1
242
Integer
19980113
19981215
Temp
Temperature
Producer defined
14.98
33.26
Degrees centigrade
19980113
19981215
Time
Time when Hydrolab record was saved
Producer defined.
00:00:08
23:59:26
HH:mm:ss
19980113
19981215
H98Midas
Table H98Midas lists sample date, time sample was collected from the
ship's MIDAS tap-in, closest MIDAS GPS time, MIDAS GPS latitude and
longitude, MIDAS tap-in salinity and weight of suspended sediments.
There are 188 records. MIDAS GPS was not functional at all stations.
See also Completeness_Report.
Producer defined.
Date
Date when the SPM (suspended sediment) sample was collected from the
survey ship's MIDAS.
Producer defined.
19980113
19981215
19980113
19981215
M-Sal
Salinity as measured by RV Pelican's SeaBird SBE 21 Thermosalinograph
in the flow-through seawater component of the ship's MIDAS system.
October salinity values reported for stations C8, C7, C6, C6B, C5, C4,
C3 and C1 are near-surface Hydrolab values.
Producer defined.
1.73
34.9
parts per thousand
19980113
19981215
SS-Lat
MIDAS GPS latitude of sampling station.
Producer defined.
28.3916
29.6937
Decimal degrees
19980113
19981215
-9999
Latitude value was recorded from the ship's differential GPS when
suspended sediment sample was collected. GPS manufacturer's accuracy
claim is 1-5 meters 95% of the time. Wind, currents and tidal forces
may move the ship from the beginning position. Survey vessel was not
anchored during sampling. Position at end of sample operations may
have changed from beginning operations location. Vessel drift was
generally less than 0.3 nm. An Accuracy value of -9999 was entered
because accuracy could not be determined.
SS-Lon
MIDAS GPS longitude of sampling station.
Producer defined.
-93.417
-89.4246
Decimal degrees
19980113
19981215
-9999
Longitude value was recorded from the ship's differential GPS when
suspended sediment sample was collected. GPS manufacturer's accuracy
claim is 1-5 meters 95% of the time. Wind, currents and tidal forces
may move the ship from the beginning position. Survey vessel was not
anchored during sampling. Position at end of sample operations may
have changed from beginning operations location. Vessel drift was
generally less than 0.3 nm. An Accuracy value of -9999 was entered
because accuracy could not be determined.
Sta
Station name of location sampled.
Producer defined.
Character field
19980113
19981215
StnID
Station identification number.
Producer defined
1
242
Integer
19980113
19981215
SuspSed
Total suspended sediments collected by tapping into the flow-through
seawater component of the ship's MIDAS system. October 1998 suspended
sediment samples were collected from twice-rinsed buckets of surface
water.
Producer defined
1.9
84.4
mg/L
19980113
19981215
TimeM
Time when SPM sample was collected
Producer defined
0:23:42
23:40:02
Hours:minutes:seconds
19980113
19981215
H98Nutrients
The table lists station NH4, NO2, NO2+NO3, NO3, PO4 and SiO3 values at
depths. There are 393 records.
Producer defined.
Depth
Depth of Hydrolab p sensor, 0.0 depth = bucket sample. 6.5m and 14m
samples were collected using Niskin bottles on the Seabird rosette.
Bottom samples were collected using a bottom-tripping Niskin bottle on
the Hydrolab Hydrowire.
Producer defined
0
68.3
Meters
19980113
19981215
NH4
Ammonium
Producer defined
0.1
27.9
µg-at/L
19980113
19981215
NO2
Nitrite
Producer defined
0.1
16.3
µg-at/L
19980113
19981215
NO2+NO3
Nitrite + Nitrate
Producer defined
0.1
150.5
µg-at/L
19980113
19981215
NO3
Nitrate
Producer defined
0
149.9
µg-at/L
19980113
19981215
PO4
Phosphate
Producer defined
0.1
4.1
µg-at/L
19980113
19981215
SiO3
Silicate
Producer defined
0.3
128.6
µg-at/L
19980113
19981215
Sta
Station name of location sampled
Producer defined
Character field
19980113
19981215
StnID
Station identification number
Producer defined
1
242
Integer
19980113
19981215
H98Pigments
The table lists sample depth, mean chlorophyll a, Fo/Fa ratio, mean
phaeopigments, mean total pigments, station name and station
identification number. There are 393 records.
Producer defined.
Date
Date station was sampled.
Producer defined.
19980113
19981215
19980113
19981215
Depth
Depth of Hydrolab p sensor, 0.0 depth = bucket sample. 6.5m and 14m
samples were collected using Niskin bottles on the Seabird rosette.
Bottom samples were collected using a bottom-tripping Niskin bottle on
the Hydrolab Hydrowire.
Producer defined
0
68.3
Meters
19980113
19981215
MeanC
Mean Chlorophyll a
Producer defined
0
38.75
µg/L
19980113
19981215
MeanF
Mean Fo/Fa ratio. F(original), F(acidified).
Producer defined
0.51
4.61
Fo/Fa ratio
19980113
19981215
MeanP
Mean Phaeopigments
Producer defined
0
49.76
µg/L
19980113
19981215
Sta
Station name of location sampled
Producer defined
Character field
19980113
19981215
StnID
Station identification number
Producer defined
1
242
Integer
19980113
19981215
Total
Total pigments
Producer defined
0.2
59.23
µg/L
19980113
19981215
H98PortaSal
The table lists sample depth and sample salinity (psu), station name
and station identification number of values measured using a Guildline
Instruments PortaSal. There are 248 records.
Producer defined.
Depth
Depth of Hydrolab p sensor, 0.0 depth = bucket sample. Bottom samples
were collected using a bottom-tripping Niskin bottle on the Hydrolab
Hydrowire.
Producer defined
0
30.5
Meters
19980113
19981215
PortaSal
Salinity
Producer defined.
0.001
35.853
psu
19980113
19981215
Sta
Station name of location sampled
Producer defined
Character field
19980113
19981215
StnID
Station identification number.
Producer defined
1
242
Integer
19980113
19981215
H98Refract
The table lists sample salinity, station name and station
identification number of values measured using a refractometer. There
are 4 records.
Producer defined
Refracto
Salinity measured with a refractometer.
Producer defined.
1
15
Parts per thousand.
19980721
19980721
Sta
Name of station sampled.
Producer defined.
Character field.
19980721
19980721
StnID
Station identification number.
Producer defined.
86
89
Integer.
19980721
19980721
Time
Time of refractometer sample.
Producer defined.
6:23
6:44
HH:MM
19980721
19980721
H98SeaBird
The table lists SeaBird CTD conductivity, depth, FlC (Chelsea
fluorometer voltage), FlS (SeaTech fluorometer voltage), dissolved
oxygen, oxygen percent saturation, salinity, density sigma-t, station
name, station identification number, temperature and light
transmissivity. There are 2825 records.
Producer defined.
COS/m
Conductivity
Producer defined.
1.482476
5.940581
S/m
19980113
19981215
DepS
Depth of SeaBird pressure sensor.
Producer defined.
0.742
67.604
Meters
19980113
19981215
FlC
in vivo fluorescence. Chelsea fluorometer voltage.
Producer defined.
0.07499
7.285
Voltage
19980113
19981215
FlS
in vivo fluorescence. SeaTech fluorometer voltage. N.B. 30 is the
maximum value for the instrument. Values of 30 indicate in vivo
fluorescence was equal to or greater than what the instrument
measured.
Producer defined.
0.5275
30
Voltage
19980113
19981215
OxMg/L
Dissolved oxygen
Producer defined.
0.00042
8.86001
mg/L
19980113
19981215
OxPS
Percent oxygen saturation.
Producer defined.
0
128.6
Percent
19980113
19981215
Sal00
Salinity
Producer defined.
7.9114
36.3431
psu
19980113
19981215
Sigma-t00
Density sigma-t
Producer defined.
1.885
26.1714
sigma-t
19980113
19981215
Sta
Station name of location sampled.
Producer defined.
Character field
19980113
19981215
StnID
Station identification number.
Producer defined.
1
242
Integer
19980113
19981215
T068
Water Temperature
Producer defined.
14.9617
32.0635
Degrees centigrade
19980113
19981215
Xmiss
Percent light transmission
Producer defined.
1.46
102.06
Percent
19980113
19981215
H98Stn
The table lists altimeter height, date, fathometer depth, latitude,
longitude, secchi disk depth, station name, station identification
number, time of Hydrolab CTD cast and time of SeaBird CTD cast. There
are 198 records.
Producer defined.
Alt
Height of SeaBird CTD package above the bottom.
Producer defined.
1.5
7
feet
19980113
19981215
Date
Date samples were collected at station. (Date may be different for
suspended sediment sample, Hydrolab CTD cast and SeaBird CTD cast at
same station).
Producer defined.
19980113
19981215
19980113
19981215
Depth
Depth of Station as measured by ship's fathometer, corrected for hull
depth.
Producer defined.
5.3
68.3
Meters
19980113
19981215
Lat
Latitude of sampling station.
Producer defined.
28.3911
29.7077
Decimal degrees.
19980113
19981215
-9999
Latitude value was recorded from the ship's differential GPS at the
beginning of sampling operations. GPS manufacturer's accuracy claim
is 1-5 meters 95% of the time. Wind, currents and tidal forces may
move the ship from the beginning position. Survey vessel was not
anchored during sampling on July shelfwide cruise. Vessel was only
occasionally anchored or tied to an oilfield structure during other
monthly cruises. Position at end of sample operations may have
changed from beginning operations location. Vessel drift was
generally less than 0.3 nm. An Accuracy value of -9999 was entered
because accuracy could not be determined.
Lon
Longitude of sampling station.
Producer defined.
-93.4167
-89.4246
Decimal degrees.
19980113
19981215
-9999
Longitude value was recorded from the ship's differential GPS at the
beginning of sampling operations. GPS manufacturer's accuracy claim
is 1-5 meters 95% of the time. Wind, currents and tidal forces may
move the ship from the beginning position. Survey vessel was not
anchored during sampling on July shelfwide cruise. Vessel was only
occasionally anchored or tied to an oilfield structure during other
monthly cruises. Position at end of sample operations may have
changed from beginning operations location. Vessel drift was
generally less than 0.3 nm. An Accuracy value of -9999 was entered
because accuracy could not be determined.
Secc
Secchi disk depth. N.B. Secchi disk depths at stations G3 and G4 on
the date 19980724 were greater than 17 meters.
Producer defined.
0.4
17
Meters
19980113
19981215
Sta
Station name of location sampled.
Producer defined.
Character field
19980113
19981215
StnID
Station identification number.
Producer defined.
1
242
Integer
19980113
19981215
TimeHL
Time of beginning of Hydrolab CTD cast as well as time of Pigment,
PortaSal and Nutrient samples.
Producer defined.
00:06:18
23:56:09
HH:mm:ss
19980113
19981215
TimeSB
Time of beginning of Seabird CTD cast.
Producer defined.
00:27
23:48
HH:mm
19980113
19981215
The related data tables H98Hydrolab, H98Midas, H98Nutrients,
H98Pigments, H98PortaSal, H98Refract, H98SeaBird, and H98Stn contain
spatial, temporal, physical and biological water quality data acquired
during the 1998 Hypoxia Surveys of the Louisiana coastal waters. Each
table contains a StnID field that can be used to key joins with other
tables.
For detailed attribute information contact N. Rabalais.
Nancy N. Rabalais
Louisiana Universities Marine Consortium
mailing address
Louisiana Universities Marine Consortium, 8124 Hwy 56
Chauvin
LA
70344
USA
985 851 2800
985 851 2874
Unknown
I, the data requestor, agree to credit the data originators in any
publications, reports or presentations generated from this data. I also
accept that although these data have been processed successfully on a
computer system at the Louisiana Universities Marine Consortium, no
warranty expressed or implied is made regarding the accuracy or utility of
the data on any other system or for general or scientific purposes, nor
shall the act of distribution constitute any such warranty. I recognize
that these data are best acquired from the originator and not from a
secondary source. I recognize that careful attention must be paid to the
contents of the metadata file associated with these data. I will not hold
Louisiana Universities Marine Consortium liable for improper or incorrect
use of the data described and/or contained herein. This disclaimer applies
both to individual use of the data and aggregate use with other data.
MDB
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LAHS1998.mdb
Contact Distributor.
None
Call or write the Distributor with requests for data sets.
Contact Distributor.
None.
Contact distributor
20030605
20030615
20130615
Ben Cole or Adam Sapp
Louisiana Universities Marine Consortium
mailing address
LUMCON, 8124 Hwy 56
Chauvin
LA
70344
USA
985 851 2800
985 851 2874
Unknown
FGDC Content Standards for Digital Geospatial Metadata
FGDC-STD-001-1998
local time