CTD sensor and nutrient measurements from R/V Yellowfin cruises to the San Pedro Ocean Time-series (SPOT) station in 2013 and 2014

Website: https://www.bco-dmo.org/dataset/685342
Data Type: Other Field Results
Version: 08 March 2017
Version Date: 2017-03-08

Project
» Collaborative Research: Use of Triple Oxygen Isotopes and O2/Ar to constrain Net/Gross Oxygen Production during upwelling and non-upwelling periods in a Coastal Setting (UpRISEE O2 upwelling)
ContributorsAffiliationRole
Haskell, WilliamUniversity of California-Santa Barbara (UCSB-MSI)Principal Investigator
Hammond, Douglas E.University of Southern California (USC)Co-Principal Investigator
Prokopenko, MariaPomona College (Pomona)Co-Principal Investigator
Rauch, ShannonWoods Hole Oceanographic Institution (WHOI BCO-DMO)BCO-DMO Data Manager


Coverage

Spatial Extent: Lat:33.55 Lon:-118.4
Temporal Extent: 2013-02-14 - 2014-06-19

Dataset Description

CTD sensor and nutrient measurements. Measurements were made at the San Pedro Ocean Time-series (SPOT) station (33 33'N, 118 24'W). Data are also published in Table C1 in the following publication:
Haskell, W. Z., et al. 2016. An organic carbon budget for coastal Southern California determined by estimates of vertical nutrient flux, net community production and export. Deep-Sea Research I, 116, 49-76. doi:10.1016/j.dsr.2016.07.003


Methods & Sampling

See complete methodology in Haskell et al. (2016). In summary: 
This study is part of an effort aimed at characterizing the biological response to upwelling at SPOT on 21 cruises between January 2013 and June 2014; the Upwelling Regime In-Situ Ecosystem Efficiency (Up.R.I.S.E.E.) study.

Nutrients: Samples for dissolved nutrient and pH analysis were collected via Niskin at 12 depths from the surface to 400 m and filtered through 0.8/0.2 um Acrodisc syringe filters. One Nalgene bottle was filled completely leaving no headspace and kept at ambient temperature for 6–8 h until return to the lab where pH was measured using a combination electrode calibrated with buffers of pH 4 and 7, referenced to NBS standards. About 20 of these samples were analyzed for alkalinity and total dissolved inorganic carbon (DIC). To make the measured pH internally consistent with the DIC and alkalinity, all pH values were increased by 0.02, the estimated uncertainty in electrode calibration. After the pH aliquot was taken, samples were refrigerated until silicic acid and phosphate analyses were done colorimetrically at USC with a Hitachi UV/vis-spectrophotometer. Nitrate samples were collected in acid-washed 60 ML HDPE Nalgene bottles and frozen at -20 degrees C until analysis. Nitrate concentrations in samples collected from January to June 2013 were determined by converting nitrate to N2O and quantifying the amount of N2O as integrated sample areas on an Isotope Ratio Mass Spectrometer (IRMS) in the D. Sigman lab at Princeton University. Prior to analyses, nitrite was chemically removed from samples. The remainder of the samples (October 2013 to June 2014) were analyzed for nitrate + nitrite and nitrite only by chemiluminescence. The analytical uncertainty for nitrate and silica concentrations is ~0.5 uM. Samples for DIC were collected at each depth by using a syringe to inject 5–7 mL of filtered water into evacuated vials through a needle-pierced septum. Following measurement of the mass of water, measurements of TCO2 and δ13C were made on a Picarro Cavity Ring-Down Spectrometer at USC. Alkalinity was calculated from DIC and pH using Mehrbach constants. On samples titrated for alkalinity, DIC calculated from the adjusted pH was within +/- 10 umol per kg (+/-1 ssd) of the measured values. Measurements were standardized with Dickson standards from SIO, and alkalinity precision was typically +/- 5 ueq per kg. DOC samples were syringe-filtered into acid-washed and combusted 40 ML borosilicate vials with silicone/PTFE septa caps (Thermo Fisher Scientific). After sampling, samples were acidified with distilled HCl to pH ~2 and refrigerated until analysis on a Shimadzu TOC-VCSN analyzer at Scripps Institute of Oceanography (L. Aluwihare lab). The analytical uncertainty on DOC concentrations based on replicates is ~ 5 uM. Each day's run included the analysis of a deep seawater community standard, and if the concentration of this standard was not between 41 and 42 uM C then all samples were re-analyzed.


Data Processing Description

CTD data was processed through the standard Seabird Seasave V7 data processing algorithm. 

BCO-DMO Processing:
-modified parameter names to conform with BCO-DMO naming conventions;
-created separate column for date and formatted to yyyy-mm-dd;
-replaced "-" and blanks (missing data) with "nd";
-added site name, lat, and lon from information on metadata form.


[ table of contents | back to top ]

Data Files

File
CTD.csv
(Comma Separated Values (.csv), 37.14 KB)
MD5:97e2fd8c1b2f386ab5a98a2b8b1087e7
Primary data file for dataset ID 685342

[ table of contents | back to top ]

Parameters

ParameterDescriptionUnits
siteName of the site unitless
latLatitude of the site decimal degrees
lonLongitude of the site decimal degrees
cruise_idCruise identifier unitless
dateDate of sampling formatted as yyyy-mm-dd unitless
year4-digit year unitless
month2-digit month unitless
day2-digit day unitless
yrdayYear day (sequential day of year, eg. Jan 1 = 1) unitless
depthSample depth meters (m)
tempTemperature degress C
salSalinity parts per thousand (ppt)
O2Oxygen concentration calibrated by Winkler titration. micromoles per kilogram (umol kg-1)
AOUApparent oxygen utilization defined as the saturation concentration of oxygen at the given temperature and salinity minus the measured oxygen concentration. micromoles per kilogram (umol kg-1)
chl_fluorChlorophyll fluorescence milligrams per cubic meter (mg m-3)
densityDensity kilograms per cubic meter (kg m-3)
pHpH; NBS scale unitless
DICDissolved inorganic carbon (DIC) micromoles per kilogram (umol kg-1)
alkAlkalinity micromoles per kilogram (umol kg-1)
DOCDissolved organic carbon (DOC) micromolar (uM)
NO3Nitrate micromolar (uM)
PO4Phosphate micromolar (uM)
H4SiO4Silicic acid micromolar (uM)


[ table of contents | back to top ]

Instruments

Dataset-specific Instrument Name
Seabird CTD
Generic Instrument Name
CTD Sea-Bird
Generic Instrument Description
Conductivity, Temperature, Depth (CTD) sensor package from SeaBird Electronics, no specific unit identified. This instrument designation is used when specific make and model are not known. See also other SeaBird instruments listed under CTD. More information from Sea-Bird Electronics.

Dataset-specific Instrument Name
Isotope Ratio Mass Spectrometer
Generic Instrument Name
Isotope-ratio Mass Spectrometer
Dataset-specific Description
N2O was quantified on an Isotope Ratio Mass Spectrometer at Princeton University.
Generic Instrument Description
The Isotope-ratio Mass Spectrometer is a particular type of mass spectrometer used to measure the relative abundance of isotopes in a given sample (e.g. VG Prism II Isotope Ratio Mass-Spectrometer).

Dataset-specific Instrument Name
Seabird SBE 43
Generic Instrument Name
Sea-Bird SBE 43 Dissolved Oxygen Sensor
Dataset-specific Description
Oxygen was measured by SBE 43 on the CTD.
Generic Instrument Description
The Sea-Bird SBE 43 dissolved oxygen sensor is a redesign of the Clark polarographic membrane type of dissolved oxygen sensors. more information from Sea-Bird Electronics

Dataset-specific Instrument Name
Shimadzu TOC-VCSN analyzer
Generic Instrument Name
Shimadzu TOC-V Analyzer
Dataset-specific Description
DOC samples were acidified with distilled HCl to pH ~2 and refrigerated until analysis on a Shimadzu TOC-VCSN analyzer at Scripps Institute of Oceanography.
Generic Instrument Description
A Shimadzu TOC-V Analyzer measures DOC by high temperature combustion method.

Dataset-specific Instrument Name
Generic Instrument Name
Spectrometer
Dataset-specific Description
Following measurement of the mass of water, measurements of TCO2 and δ13C were made on a Picarro Cavity Ring-Down Spectrometer at USC.
Generic Instrument Description
A spectrometer is an optical instrument used to measure properties of light over a specific portion of the electromagnetic spectrum.

Dataset-specific Instrument Name
Hitachi UV/vis-spectrophotometer
Generic Instrument Name
Spectrophotometer
Dataset-specific Description
Silicic acid and phosphate analyses were done colorimetrically at USC with a Hitachi UV/vis-spectrophotometer.
Generic Instrument Description
An instrument used to measure the relative absorption of electromagnetic radiation of different wavelengths in the near infra-red, visible and ultraviolet wavebands by samples.

Dataset-specific Instrument Name
chemiluminescence
Generic Instrument Name
Chemiluminescence NOx Analyzer
Dataset-specific Description
The remainder of the samples (October 2013 to June 2014) were analyzed for nitrate + nitrite and nitrite only by chemiluminescence.
Generic Instrument Description
The chemiluminescence method for gas analysis of oxides of nitrogen relies on the measurement of light produced by the gas-phase titration of nitric oxide and ozone. A chemiluminescence analyzer can measure the concentration of NO/NO2/NOX. One example is the Teledyne Model T200: https://www.teledyne-api.com/products/nitrogen-compound-instruments/t200


[ table of contents | back to top ]

Deployments

UpRISEE_SPOT_13-14

Website
Platform
R/V Yellowfin
Start Date
2013-01-16
End Date
2014-06-19
Description
A series of cruises were conducted from January 2013 to June 2014 to the San Pedro Ocean Time-Series (SPOT) station. These cruises were part of a study aimed at characterizing the biological response to upwelling at SPOT: the Upwelling Regime In-Situ Ecosystem Efficiency (Up.R.I.S.E.E.) study.


[ table of contents | back to top ]

Project Information

Collaborative Research: Use of Triple Oxygen Isotopes and O2/Ar to constrain Net/Gross Oxygen Production during upwelling and non-upwelling periods in a Coastal Setting (UpRISEE O2 upwelling)

Coverage: Northeast Pacific Ocean


The marine biological pump is one of the primary pathways via which anthropogenic carbon dioxide may be sequestered from the atmosphere and exported to the deep ocean as organic carbon. While the link between nutrient supply and high primary productivity in upwelling regions is well established, factors controlling the organic carbon export efficiency of upwelling ecosystems are not well known. Scientists from the University of Southern California and Pomona College plan to determine the factors that control the rates and magnitudes of two components of biological production, Net Community Production (NCP) and Gross Primary Production (GPP), as well as particulate organic carbon export efficiency, at the San Pedro Ocean Time Series, a coastal site in the California Borderland during periods of minimal and high upwelling velocity over a 2-year span. At this site, past and ongoing observations of hydrography and carbon rain will provide an historical context for interpreting results and mechanisms at work.

Rates of NCP and GPP will be quantified at different upwelling intensity, using dissolved oxygen to argon (O2/Ar) ratios and the oxygen triple isotope composition of dissolved oxygen (O2). The export of organic carbon will be established using 234Th (thorium) profiles in the water column, coupled with floating sediment trap deployments, and the development of a carbon isotope balance for the water column. Upwelling will be characterized using non-steady state budgets for atmospheric 7Be (beryllium) input and its depth-integrated decay, as well as estimating rates based on remote measurements of wind stress curl and budgets for dissolved inorganic carbon and silicon. Application of the O2/Ar ratio and the oxygen triple isotope approach will require depth-integrated profiles of these tracers to evaluate the impact of upwelling on mixed layer inputs and use of non-steady state models during seasonal transitions in upwelling. The comprehensive data set to be obtained should provide insights into the organic carbon export efficiency under variable upwelling regimes and help to relate the satellite-based measurements of chlorophyll to the organic carbon export of these highly productive ecosystems.

Broader Impacts: One graduate and one undergraduate student from the University of Southern California and two undergraduate students from Pomona College would be supported and trained as part of this project.



[ table of contents | back to top ]

Funding

Funding SourceAward
NSF Division of Ocean Sciences (NSF OCE)
NSF Division of Ocean Sciences (NSF OCE)

[ table of contents | back to top ]