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Data Set of the 1988 Black Sea Oceanographic Expedition R/V Knorr

1988 Knorr Black Sea expedition stations positionThis dataset contains hydrographic data (including light transmission and fluorometer) and inorganic nutrient chemistry, sulfide and oxygen (bottle and pumpcast) data of the 1988 Knorr Black Sea expedition ( Woods Hole Oceanographic Institutuion, USA, from April to August 1988).

Sources of data: hydrographic data with resolution 1 m were obtained from Institute of Marine Sciences (IMS-METU, Erdemli, Turkey); bottle and pumpcast hydrochemical data were obtained from WHOI.


List of the loaded parameters:


Numbering of stations:

The four-digit station numbers are used for each cast. The first digit is the cruise number (1, 2, 3, 4). The second digit is as follows: 0 - for standard (routine) casts; 5 - for additional hydrographic casts named bskpump?.dat in initial data set: 1501 for bskpump.dat, 1502 for bskpump4.dat, 1503 for bskpump5.dat, 1504 for bskpump6.dat, 1505 for bskpump7.dat, 1506 for bskpump8.dat, 1507 for bskpump9.dat; 9 - hydochemical pumpcasts. The third and fourth digits are the cast number from the header files.


Corrections made in data during the loading:

Some wrong coordinates of stations were corrected; Small negative values in chemical data were repleced with 0 (zero); Nonexistent values were replaced with -88 (minus eighty eight).


Data base was loaded at the MHI Data Base Laboratory in 1995.

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SPECIAL REPORT NO.109 (selected information)

HYDROGRAPHIC DATA FROM THE 1988 BLACK SEA OCEANOGRAPHIC EXPEDITION

By George White Mike Relander James Postel and James W.Murray
School of Oceanography University of Washington Seattle, Washington 98195

Introduction

The Black Sea Oceanographic Expedition was conducted on the R/V KNORR from April to August of 1988. This expedition consisted of five cruises organized by U.S. and Turkish scientists to study all major aspects of the oceanography of this unique environment. The U.S. and Turkish coordinating committees met in Izmir, Turkey in June 1987. The 1988 expedition grew out of this meeting. A total of 111 scientists from 39 universities and institutions from 8 countries participated in the 5 cruises that were conducted from 16 April to 29 july 1988. Each cruise had its own emphasis and a summary of the scientific projects conducted is shown below. Overall, the objective of Cruise 1 was to study the sedimentary evolution of the Black Sea by examining particle fluxes and sediment cores. Cruise 2 focused on the microbiology of the carbon, nitrogen and sulfur cycles. The emphasis of Cruise 3 was the cycling of trace metals and nutrients across the anoxic interface. Cruise 4 had two objectives. The first was study circulation and mixing using oceanographic tracers.The second was to study the sedimentary geochemistry and depositional history. A study of nitrogen and carbon cycle distributions and microbiology was conducted on Cruise 5. Each Cruise had its own sampling requirements and the station locations are given in Cruise Chart. In some cases the stations were occupied over a considerable period of time. The exact coordinates for specific hydrocasts should be obtained from the data pages in this report. For more information about projects and data on the different cruises consult the respective chief scientists.

Hydrographic Data

The data in this report were collected using a rosette-CTD package eqquipped with 12-301 or 12-51 Go-Flo Niskin type bottles. The rosette also contained a Sea Tech transmissometer and fluorometer. CTD - The pressure, temperature and conductivity data were acquired using a Seabird SBE-9/11 CTD. Calibrations of the three sensors were made in March and September 1988, before and after the Black Sea Expedition. All calibrations were conducted by the Northwest Regional Calibration Center, operated under contract to NOAA. The offset for each sensor drifted slightly over the duration of the expedition and the corrections applied are described below. The CTD pressure sensor is a Paroscientific Digiquartz. The pressure sensor has an intermal temperature sensor which can be used to compensate for temperature effects. The overall accuracy of this sensor over the ocean temperature range is about 0.02% of full scale (10,000 psia=6900 m) or 1.38 db. The pressure offset (db) over the duration of the expedition averaged 8.0+0.3 db. This offset is the pressure read just above the sea surface. There was a slow systematic draft in the offset over the 4 month period as shown in Figure 2. We fit a least squares regression to this drift and, using this equation, estimated a value of the offset for each cruise. Values were chosen for the mid date of the cruise and used for all of the hydrocasts during that cruise. The pressure offsets we estimated are shown in Figure 2 and varied from - 7.66 db for cruise 1 to - 8.30 db for cruise 5. The CTD temperature sensor is a 0.4 mm OD thermistor. This instrument has an absolute accuracy of 0.01 degree C per 6 months guaranteed with 0.004 degree C typical. The temperature offset varied from 0.00061 grad C for cruise 1 to 0.00251 grad C for cruise 5. Temperature offsets appropriate for each cruise were obtained from a linear extrapolation between the calibration end points. The values adopted are shown in Figure 3. The CTD conductivity sensor uses three platinum electrodes in a pyrex tube as a sensing element. Absolute accuracy is 0.001 siemens/meter per month guaranteed and 0.003 siemens/meter per year. The conductivity offset varied from -0.00012 S/M to -0.00048 from cruise 1 to cruise 5 and the constant values applied to the data from each cruise are given in Figure 4. The CTD data were processed following the procedures and recommendations given in UNESCO Report No.54 (1988). The new data were edited by calculating the standard deviation on blocks of 24. Data with a standard deviation greater than 2.8 times the mean were replaced by data obtained by linear interpolation. This edited data was then filtered using a digital low pass filter that reduces the high frequency noise. A lag correction was applied to the pressure data as described in the SeaBird manual. The pressure, temperature and conductivity offsets were then introduced. This edited and filtered data were then compacted and interpolated to the nearest 1 meter bin. The complete 1 m data file for each cast is on disk. For the purpose of this data report the data are given for every 2 m from 0 to 100 m, every 5 m from 100 to 250 m and then every 25 m from 250 m to the maximum depth. This degree of detail should be sufficient for most investigators. If anyone desires the raw data or the 1 m data files they can be obtained by contacting George White at the University of Washington.

Light Transmission

The Sea Tech Transmissometer was calibrated in air before and after the expedition, and this data has been corrected using these offsets. Data are given here as % transmission.

Fluorometer

The Sea Tech fluorometer was not calibrated at sea against manual chlorophyll measurements. Note that the sensitivity was charged on Cruise 2 in order to obtain better resolution. The response was increased by decreasing the time constant from 3 sec to 1 sec. It was left in this mode for the rest of the cruises. The fluorometer was not turned on for most deep casts and for most of the casts on cruise 3. For these casts, zeros are given in the data column. The fluorometer data is not generally shown in the figures of this report because the instrument was not directly calibrated against pigment analyses during the Expedition. The data may be of qualitative use, however. An example of the fluorescence and transmission data plotted together is shown in figure 5 for cast 32 from cruise 1.

References

  1. Unesco (1983) Algorithms for computation of fundamental properties of seawater. Unesco technical papers in marine science. No.44. 75 pp.
  2. Unesco (1988) The acquisition, calibration and analysis of CTD data. Unesco technical papers in marine science. No. 54. 92 pp.

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Scientific Projects, 1988 Black Sea Oceanographic Expedition

Cruise 1

Cruise 2

Cruise 3

Cruise 4

Water column tracers of circulation and mixing:

Sedimeht geochemistry:

Cruise 5


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Bottle and Pumpcast Data from the 1988 Black Sea Expedition

MBARI Technical Report No. 90-3 Gernot E. Friederich Louis A. Codispoti Carole M. Sakamoto Monterey Bay Aquarium Research Institute, 160 Central Avenue Pacific Grove, CA 93950 408-647-3700

Introduction

This report contains inorganic nutrient chemistry, sulfide and oxygen data collected during cruises 2 through 5 of the 1988 Black Sea Oceanographic Expedition aboard the R/V Knorr. Continuous nutrient and sulfide data were obtained in the upper 375 m using a pumped profiling system. Discrete samples were collected from rosette-CTD casts. The corresponding physical oceanographic data have been presented by White et al. (1989). Although all of the data reported has been edited at least twice, errors may remain. We encourage queries and plan to distribute updates on electronic media if there are any non-trivial changes.

Analysts

Pump Casts

The profiling pump system was based on a prototype described by Friederich and Codispoti (1987). A hydraulic winch was used to deploy 400 m of cable to which the pump and a Seabird SBE-9/11 CTD were attached. The winch was designed to give smooth lowering speeds from near 0 to 20 m per min. Tests during very calm conditions indicated that lowering speeds less then 6 m per min did not resolve any additional water column structure in the region of the highest gradients. Consequently lowering speeds of 6-10 m per min were used for the profiles presented in this report. The center of the pump cable was a continuous nylon hose with an internal diameter of 6 mm. The hose was surrounded by a Kevlar strength member; electrical conductors for data and power transmission formed the next layer. A Dacron braid formed the outer jacket. The pump was a stainless steel and graphite positive displacement vane pump, coupled to a submersible deep well pump motor. The flow rate of about 4 l per min resulted in a travel time through the pump tubing of about 3 minutes. Delay times for the entire system including the time for each chemical analysis were derived for each cast. Most delay times were obtained by stopping the pump/CTD system for a short time during a profile and then matching the plateau generated in the chemical profile with that of the CTD pressure readings. A few delay times were derived by injecting enriched water into the pump intake while it was held in a tank on deck. Data was recorded to disk from all chemistry channels and from the CTD every three seconds during each cast. All pump data was averaged in 1 decibar (db) bins. The complete 1 db data files are available on disk. For the purpose of this report data are given in 2 db increments between the surface and 150 db and in 5 db increments below 150 db.

Inorganic Nutrients

Nutrient analysis of both the pump profiles and the bottle samples were made using a computer controlled (Hewlett-Packard Series 85) Alpkem Rapid Flow Analysis (RFA) system. Ammonium, nitrite, phosphate and dissolved silicon measurements were made using slight modifications of the methods described by Whitledge et al.(1981). Nitrate was measured using a slight modification of the method supplied by Alpkem which is based on the work of Patton (1982). In order to eliminate the interference of sulfide in the analysis of phosphate, dissolved silicon and ammonium; bottle samples from the anoxic zone were stripped with nitrogen for about 20 min. The amount of potassium antimony tartrate in the phosphate analysis was doubled in order to reduce sulfide interference. Nitrate levels decreased to undetectable levels just above the sulfide bearing waters and it was therefore not necessary to measure nitrate in the sulfidic waters. Nitrate analysis were occasionally performed on stripped samples from sulfide bearing waters near the oxic/anoxic interface to confirm the absence of nitrate in sulfidic water. During pump casts, the only precautions taken for sulfide interference were disconnecting the nitrate channel at about the depth were sulfide first appeared and the doubled potassium antimony tartrate concentration used in the phosphate analysis. Intercomparisons between pump and bottle data suggested that other precautions were not necessary for the sulfide concentrations encountered during pump casts.

Sulfide

Continuous sulfide determinations were made from the pump stream using a continuous flow adaptation of the method developed by Cline (1969). Samples from the rosette casts, however, could not be analyzed with this method since considerable loss of sulfide occurred in the interval between sampling and analysis (< 15 min.).

Oxygen

Dissolved oxygen concentrations in bottle samples were measured using the Chesapeake Bay version of the Winkler titration (Carpenter, 1965). During some pump casts the low concentration colorimetric method of Broenkow and Cline (1969) was employed at concentrations less than 25 ?M on discrete samples collected during the pump cast. When collecting these samples the pump was held at selected depths for about 5 minutes to ensure complete flushing of the pump tube.

CTD

The CTD system on the pump package was a Seabird SBE-9/11 identical to the one used on the rosette system. During cruise 4 and 5 a Sea Tech transmissometer was added to the pump package. Each CTD data record taken during the pump casts consisted of an average of six scans taken over a period of 0.25 seconds.

Data Quality

CTD data listed with the bottle casts was taken from the upcast of the rosette-CTD system. These data have not been corrected for the drift of the CTD as given by White et al. (1988). The above omission should cause errors smaller than 0.0025 Deg. C in temperature and 0.005 ppt. in salinity During these cruises leaking bottles and out of sequence tripping of bottles on the rosette were encountered. We hope to have eliminated most of the data points plagued by these problems. The CTD system coupled to the pump was calibrated before the cruise but it was not possible to perform a post cruise calibration. Comparison with the rosette-CTD system and occasional salinity determinations of pumped water on an Autosal salinometer indicated that the data are reliable to at least .01 deg. C in temperature and .01 ppt. in salinity. Due to the large range of phosphate, dissolved silicon, ammonium and sulfide concentrations, the detection limit for these methods was larger than for more typical marine environments. Ammonium data in the oxygenated zone are unlikely to have any meaning since concentrations were of the same magnitude as the noise. An additional problem that degraded data quality was the interference of sulfide in the analysis of phosphate and to a lesser extent in the analysis of dissolved silicon and ammonium. The extra manipulation necessary to remove excess sulfide from the samples prior to analysis increased the risk of contamination and sample degradation. Another problem that effected some of the dissolved silicon data was the poor control of laboratory temperature which could vary as much as 15 deg. C over the course of a few hours. At all times at least two independent nutrient standards were maintained and intercomparisons of the various standards used during these cruises assured the absence of any systematic calibration errors. In addition to the full calibration curves, most analytical runs were accompanied by single point standards that could be used to correct drift due to such factors as temperature. In a few instances dissolved silicon data was normalized using deep samples from the same location as internal standards. Sulfide standards were titrated with thiosulfate and simultaneously analyzed in the RFA system. The estimates for accuracy given in the table below are a best estimate based on replicate standards, replicate deep samples, comparisons on isopycnal surfaces and our knowledge of various analytical problems encountered during these cruises. Richard Mortlock provided us with results from his high precision phosphate analysis to help in our assessment of data quality. These comparisons suggest:

Detection High Range Analysis Range (然) Limit (然) Error (+/- 然)
Ammonium 0 - 100 0.5 2
Nitrate 0 - 10 0.05 0.2
Nitrite 0 - 5 0.02 0.1
Phosphate 0 - 10 0.05 0.2
Silicon 0 - 350 2 10
Sulfide 0 - 200 1 10

At intermediate values the expected error should be between the detection limit and the high range error. Due to the method of assessment the high range error cannot be expressed as a statistical quantity, but it should be roughly equivalent to one standard deviation. Due to the configuration of the pumping system during cruise 5 a systematic offset appears to have been introduced to the ammonium profiles during cruise 5. The pump profiles on this disc have been corrected for this offset.

Acknowledgements

This research was supported by National Science Foundation grant OCE-8614400. Financial support was also provided by the Monterey Bay Aquarium Research Institute. We thank the crew of the R/V Knorr for their assistance during the field work and their help in the repair of mechanical problems. C. Goyet assisted with some of the initial colorimetric oxygen determinations. A.Gough's secretarial assistance is also much appreciated.

References

  1. Carpenter, J.H. (1965) The Chesapeake Bay Institute technique for the Winkler dissolved oxygen method. Limnol. Oceanogr., 10, 141-143.
  2. Broenkow, W. W. and J.D. Cline (1969) Colorimetric determination of dissolved oxygen at low concentrations. Limnol. Oceanogr., 14, 450-454.
  3. Cline, J.D. (1969) Spectrophotometric determination of hydrogen sulfide in natural waters. Limnol. Oceanogr., 14, 454-458.
  4. Friederich, G. E. and L. A. Codispoti (1987) An analysis of continuous vertical nutrient profiles taken during a cold-anomaly off Peru. Deep-Sea Research 34, 1049-1065.
  5. Patton, C. J., Doctoral Dissertation, Michigan State University, 1982, pp. 87-121
  6. White, G., M. Relander, J. Postal and J. W. Murray (1989) Hydrographic data from the 1988 Black Sea Oceanographic Expedition. University of Washington School of Oceanography Special Report No. 109.
  7. Whitledge, T. E., S. C. Malloy, C. J. Patton and C. O. Wirick (1981) Automated nutrient analysis in seawater. Brookhaven National Lab Report 51398, 216 pp.

Table of Units

Hydrocast Sequential cast number used by White et al.(1989) Pumpcast Sequential pumpcast number Latitude In degrees and decimal degrees Longitude In degrees and decimal degrees Date Greenwich Julian day and decimal day Depth Pressure in decibars Temperature In degrees Celsius Salinity In practical salinity units Sigma-t In kg per cubic meter Light transmission Per cent transmission at 660 nm Oxygen In milliliters of oxygen per liter at NTP or micro molar (ml O2/l = .0224 x 然) Low Conc. Oxygen Micro molar Phosphate Micro molar reactive phosphorous Dissolved Silicon Micro molar Nitrate Micro molar (corrected for nitrite) Nitrite Micro molar Ammonium Micro molar Sulfide Micro molar Null values -999 (any 0 in %transmission also indicates no data).


Download 1988 Knorr Black Sea expedition Chemical Dataset (233K zip file)

Download 1988 Knorr Black Sea expedition Physical Dataset (1569K zip file)

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