Particulate organic carbon (POC) and nitrogen (PON) along US GEOTRACES North Atlantic Transect from the R/V Knorr KN199-04 cruise in the subtropical N. Atlantic from 2010 (U.S. GEOTRACES NAT project)

Website: https://www.bco-dmo.org/dataset/3851
Data Type: Cruise Results
Version: 1
Version Date: 2013-01-10

Project
» U.S. GEOTRACES North Atlantic Transect (U.S. GEOTRACES NAT)

Program
» U.S. GEOTRACES (U.S. GEOTRACES)
ContributorsAffiliationRole
Chaves, JoaquinNational Aeronautics and Space Administration (NASA)Principal Investigator
McClain, CharlesNational Aeronautics and Space Administration (NASA)Co-Principal Investigator
Kinkade, DanieWoods Hole Oceanographic Institution (WHOI BCO-DMO)BCO-DMO Data Manager

Abstract
Particulate organic carbon (POC) and nitrogen (PON) along US GEOTRACES North Atlantic Transect from the R/V Knorr KN199-04 cruise in the subtropical N. Atlantic from 2010.


Coverage

Spatial Extent: N:38.3296 E:-9.6604 S:17.3581 W:-24.4962
Temporal Extent: 2010-10-17 - 2010-11-02

Dataset Description

Particulate organic carbon (POC) and nitrogen (PON) from surface samples collected on Whatman, 2.5cm  glass fiber filters (GFF). Samples were collected during Geotraces 2010 (kn199-04).

Additional Dataset Information extracted from original file header:

/begin_header                                               
/investigators=Joaquin_Chaves    Charles_McClain                                           
/affiliations=NASA                                               
/contact=joaquin.chaves@nasa.gov                                               
/experiment=GEOTRACES                                                
/cruise=kn199-04                                               
/station=NA                                               
/data_file_name=kn199-04_POC_N_BCODMO.csv                                               
/documents=POC_Pkn_Elmer_2400.pdf                                               
/calibration_files=kn199-04_POC_run.pdf                                               
/data_type=bottle                                               
/data_status=final                                               
/start_date=20101017                                               
/end_date=20101102                                               
/start_time=11:20:00[GMT]                                               
/end_time=17:10:00[GMT]                                               
/north_latitude=38.3296[DEG]                                               
/south_latitude=17.3581[DEG]                                               
/east_longitude=-9.6604[DEG]                                               
/west_longitude=-24.4962[DEG]                                               
/water_depth=-999                                               
/measurement_depth=-999                                               
/secchi_depth=-999                                               
/wind_speed=-999                                               
/cloud_percent=-999                                               
/wave_height=-999                                               
!                                               
!The field "replicates" indicates how many replicate samples were                                               
!averaged to produce the reported value   

-----

NOTE:  The following header line was incorrect and subsequently corrected by BCO-DMO                                   
! sample_no==-999 were collected with NASA's surface peristaltic pump                                           
----

! quality = 1 good; 2 = medium; 3 = suspect                                       
!                                           
/missing=-999                                           
/delimiter=comma   


Acquisition Description

Sampling Excerpt from associated file: Determination of Carbon and Nitrogen collected on Whatman glass fiber filters (GFF)

Water samples are filtered through 2.5 cm pre-combusted Whatman GFF filters using an all-glass filtering funnel. Once enough material has been accumulated on the filter the samples are stored in Nalgene 1.8 mL cryovials at -80°C until analysis. For shipping, samples are stored in liquid nitrogen dry-shippers. Prior to analysis samples are thawed and dried overnight at 65°C inside the uncapped cryovials. Dry samples in the uncapped vials are transferred overnight to a desiccator saturated with HCl fumes to remove particulate inorganic carbon present in the sample. The air in the desiccator is kept saturated by leaving concentrated HCl in an open container in the lower compartment of the desiccator. Acid–treated samples are transferred back to a 65°C oven overnight, after which can be stored capped in cryovials for extended periods prior to analysis in elemental analyzer.

For analysis the samples are wrapped in tin foil discs (PE N241-1363) and pelletized on a Parr Pellet press.

The samples are analyzed in the Perkin Elmer CHNS/O Analyzer 2400 Series II. The manufacturer’s data management software for the elemental analyzer is set up so that the analysis report includes the zero read (ZR), and the carbon and nitrogen signals (CS, NS) from the instrument for each analyzed sample.

For complete analysis and processing details, see the Supplemental Document: Determination of Carbon and Nitrogen collected on Whatman glass fiber filters (GFF) (POC_Pkn_Elmer_2400.pdf).


Processing Description

Data are averages of samples replicates, the number of which is indicated as a data column. Standard deviation of replicates is included as a data column as well. Data has been visually QA/QC. Samples runs results are compared against NIST 'Buffalo River sediment' reference material and Perkin Elmer Acetanylide runs.

Data processing and calibration is performed in Matlab using a script that generates a data report that includes the C and N content in mg for each filter replicate sample. For details on processing and calibration, please see the accompanying Supplemental Documents (kn199-04_POC_data_process.pdf)

BCO-DMO Processing Notes:
- Parameter header names were renamed to BCO-DMO convention
- Edited blank data fields and data reported as -999 to 'nd'
- Edited time to remove colons and drop unused seconds
- Edited precision of lat/lon to four decimals.
- Edited precision of POC, PON, PON_sd and POC_sd to one decimal.
- Removed the following header information from the file. Where necessary the information was incorporated into BCO-DMO metadata fields and retained entirely as 'additional information':

NOTE: The value -999 in the original file "sample" parameter, was used represent samples taken with a surface pump. This value was set by the PI, to indicate NASA's pump. However, correspondence with the PI on 2013.01.12, has corrected header note regarding sample numbers.

Therefore, the comment retained in the header has been edited to the following text, as per the PI, and sample numbers of -999 have been changed to 'nd' and additional metadata in the sample number parameter indicates that samples wtih GEOTRACES numbers had corresponding pigment samples taken, those with 'nd' did not:

# Samples from station 1 with 0 depth were collected with WHOI's GEOTRACES pump
# Sample numbers for stations > 1 with depth = 0 were collected with NASA's
# surface peristaltic pump

Additional GEOTRACES Processing: After the data were submitted to the International Data Management Office, BODC, the office noticed that important identifying information was missing in many datasets. With the agreement of BODC and the US GEOTRACES lead PIs, BCO-DMO added standard US GEOTRACES information, such as the US GEOTRACES event number, to each submitted dataset lacking this information. To accomplish this, BCO-DMO compiled a 'master' dataset composed of the following parameters: station_GEOTRC, cast_GEOTRC (bottle and pump data only), event_GEOTRC, sample_GEOTRC, sample_bottle_GEOTRC (bottle data only), bottle_GEOTRC (bottle data only), depth_GEOTRC_CTD (bottle data only), depth_GEOTRC_CTD_rounded (bottle data only), BTL_ISO_DateTime_UTC (bottle data only), and GeoFish_id (GeoFish data only). This added information will facilitate subsequent analysis and inter comparison of the datasets.

Bottle parameters in the master file were taken from the GT-C_Bottle_GT10, GT-C_Bottle_GT11, ODF_Bottle_GT10, and ODF_Bottle_GT11 datasets. Non-bottle parameters, including those from GeoFish tows, Aerosol sampling, and McLane Pumps, were taken from the Event_Log_GT10 and Event_Log_GT11 datasets. McLane pump cast numbers missing in event logs were taken from the Particulate Th-234 dataset submitted by Ken Buesseler.

A standardized BCO-DMO method (called “join”) was then used to merge the missing parameters to each US GEOTRACES dataset, most often by matching on sample_GEOTRC or on some unique combination of other parameters.

If the master parameters were included in the original data file and the values did not differ from the master file, the original data columns were retained and the name of the parameters were changed from the PI-submitted names to the standardized master names. If there were differences between the PI-supplied parameter values and those in the master file, both columns were retained. If the original data submission included all of the master parameters, no additional columns were added, but parameter names were modified to match the naming conventions of the master file.

See the dataset parameters documentation for a description of which parameters were supplied by the PI and which were added via the join method.


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Supplemental Files

File
Determination of Carbon and Nitrogen collected on Whatman glass fiber filters (GFF)
filename: POC_Pkn_Elmer_2400.pdf
(Portable Document Format (.pdf), 284.54 KB)
MD5:f3209fcecc2025842b5478c6d99b0701
Determination of Carbon and Nitrogen collected on Whatman glass fiber filters (GFF)
Processing and calibration information for the GT10 - POC_PON dataset
filename: kn199-04_POC_data_process.pdf
(Portable Document Format (.pdf), 196.13 KB)
MD5:ef052e36dd1e07e5807fb39209e89adb
Processing and calibration information for the GT10 - POC_PON dataset.

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Parameters

ParameterDescriptionUnits
latLatitude component of geographic position where samples were collected. decimal degrees
lonLongitude component of geographic position where samples were collected. decimal degrees
time_gmtTime of sampling, reported in GMT. in the format hhmm unitless
yrday_gmtYear day recorded in GMT time, where Jan 1 is day 1. unitless
date_gmtDate, recorded in GMT time. in the format yyyymmdd unitless
depthSample depth in meters.  meters
POCParticulate organic carbon milligrams/m^3
POC_sdStandard deviation of POC measurements. milligrams/m^3
PONParticulate organic nitrogen. milligrams/m^3
PON_sdStandard deviation of PON measurements. milligrams/m^3
replicateA number indicating how many replicate samples were averaged to produce the reported value. dimensionless
cruise_idOfficial cruise identifier e.g. KN199-04 = R/V Knorr cruise number 199-04. dimensionless
station_GEOTRCGEOTRACES station number; ranges from 1 through 12 for KN199-04 and 1 through 24 for KN204-01. Stations 7 and 9 were skipped on KN204-01. PI-supplied values were identical to those in the intermediate US GEOTRACES master file. Originally submitted as 'station', this parameter name has been changed to conform to BCO-DMO's GEOTRACES naming conventions. dimensionless
cast_GEOTRCCast identifier numbered consecutively within a station. Values were added from the intermediate US GEOTRACES master file (see Processing Description). dimensionless
event_GEOTRCUnique identifying number for US GEOTRACES sampling events; ranges from 2001 to 2225 for KN199-04 events and from 3001 to 3282 for KN204-01 events. Values were added from the intermediate US GEOTRACES master file (see Processing Description). dimensionless
sample_GEOTRCUnique identifying number for US GEOTRACES samples; ranges from 5033 to 6078 for KN199-04 and from 6112 to 8148 for KN204-01. PI-supplied values were identical to those in the intermediate US GEOTRACES master file Originally submitted as 'sample_no'; this parameter name has been changed to conform to BCO-DMO's GEOTRACES naming conventions. Unique sample identifier, where sample numbers from station 1 were collected with WHOI's GEOTRACES pump and samples for stations > 1 were collected with NASA's surface peristaltic pump. Samples with a GEOTRACES sample number also had pigment samples collected, missing sample numbers (nd) did not. dimensionless
sample_bottle_GEOTRCUnique identification numbers given to samples taken from bottles; ranges from 1 to 24; often used synonymously with bottle number. Values were added from the intermediate US GEOTRACES master file (see Processing Description). dimensionless
bottle_GEOTRCAlphanumeric characters identifying bottle type (e.g. NIS representing Niskin and GF representing GOFLO) and position on a CTD rosette. Values were added from the intermediate US GEOTRACES master file (see Processing Description). dimensionless
depth_GEOTRC_CTDObservation/sample depth in meters; calculated from CTD pressure. Values were added from the intermediate US GEOTRACES master file (see Processing Description). meters
BTL_ISO_DateTime_UTCDate and time (UTC) variable recorded at the bottle sampling time in ISO compliant format. Values were added from the intermediate US GEOTRACES master file (see Processing Description). This standard is based on ISO 8601:2004(E) and takes on the following form: 2009-08-30T14:05:00[.xx]Z (UTC time) format: YYYY-MM-DDTHH:MM:SS[.xx][+/-TZ] yyyy-MM-dd'T'HH:mm:ss.SS'Z'


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Instruments

Dataset-specific Instrument Name
Pump surface
Generic Instrument Name
Pump surface
Dataset-specific Description
NASA's surface peristaltic pump was used to collect some samples.
Generic Instrument Description
A source of uncontaminated near-surface seawater pumped onto the deck of the research vessel that can be sampled and analyzed. This pumped seawater supply is from an over-the-side pumping system, and is therefore different from the vessel underway seawater system.

Dataset-specific Instrument Name
CHN Elemental Analyzer
Generic Instrument Name
CHN Elemental Analyzer
Dataset-specific Description
Perkin Elmer CHNS/O Analyzer 2400 Series II: The PE 2400 is a commercially available elemental analyzer that uses a combustion method to convert the sample elements to simple gases (CO2, H2O, and N2). The sample is first oxidized in a pure oxygen environment. Elements such as halogens and sulfur are removed by scrubbing reagents in the combustion zone. The resulting gases are homogenized and controlled to exact conditions of pressure, temperature, and volume. The homogenized gases are allowed to de-pressurize trough a column where they are separated in a stepwise, steady-state manner and measured as a function of their thermal conductivities.
Generic Instrument Description
A CHN Elemental Analyzer is used for the determination of carbon, hydrogen, and nitrogen content in organic and other types of materials, including solids, liquids, volatile, and viscous samples.


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Deployments

KN199-04

Website
Platform
R/V Knorr
Report
Start Date
2010-10-15
End Date
2010-11-04
Description
This cruise constitutes the first survey section as part of the U.S. participation in an international program named GEOTRACES. Funding: NSF OCE award 0926423 Science Objectives: To obtain state of the art trace metal and isotope measurements on a suite of samples taken on a mid-latitude zonal transect of the North Atlantic. In particular, sampling targeted the oxygen minimum zone extending off the west African coast near Mauritania, the TAG hydrothermal field, and the western boundary current system along Line W. For additional information, please refer to the GEOTRACES program Web site (https://www.geotraces.org/) for overall program objectives and a summary of properties measured. Science Activities include seawater sampling via GoFLO and Niskin carousels, in situ pumping (and filtration), CTDO2 and transmissometer sensors, underway pumped sampling of surface waters, and collection of aerosols and rain. Hydrography, CTD and nutrient measurements were supported by the Ocean Data Facility (J. Swift) at Scripps Institution of Oceanography and funded through NSF Facilities. They provided an additional CTD rosette system along with nephelometer and LADCP. A trace metal clean Go-Flo Rosette and winch were provided by the group at Old Dominion University (G. Cutter) along with a towed underway pumping system. Additional cruise information is available from the Rolling Deck to Repository (R2R): https://www.rvdata.us/search/cruise/KN199-04 Other Relevant Links: List of cruise participants: [ PDF ] Cruise track: JPEG image (from Woods Hole Oceanographic Institution, vessel operator) ADCP data are available from the Currents ADCP group at the University of Hawaii: KN199-04 ADCP


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Project Information

U.S. GEOTRACES North Atlantic Transect (U.S. GEOTRACES NAT)


Coverage: Subtropical western and eastern North Atlantic Ocean (GA03)


Much of this text appeared in an article published in OCB News, October 2008, by the OCB Project Office.

The first U.S. GEOTRACES Atlantic Section will be specifically centered around a sampling cruise to be carried out in the North Atlantic in 2010. Ed Boyle (MIT) and Bill Jenkins (WHOI) organized a three-day planning workshop that was held September 22-24, 2008 at the Woods Hole Oceanographic Institution. The main goal of the workshop, sponsored by the National Science Foundation and the U.S. GEOTRACES Scientific Steering Committee, was to design the implementation plan for the first U.S. GEOTRACES Atlantic Section. The primary cruise design motivation was to improve knowledge of the sources, sinks and internal cycling of Trace Elements and their Isotopes (TEIs) by studying their distributions along a section in the North Atlantic (Figure 1). The North Atlantic has the full suite of processes that affect TEIs, including strong meridional advection, boundary scavenging and source effects, aeolian deposition, and the salty Mediterranean Outflow. The North Atlantic is particularly important as it lies at the "origin" of the global Meridional Overturning Circulation.

It is well understood that many trace metals play important roles in biogeochemical processes and the carbon cycle, yet very little is known about their large-scale distributions and the regional scale processes that affect them. Recent advances in sampling and analytical techniques, along with advances in our understanding of their roles in enzymatic and catalytic processes in the open ocean provide a natural opportunity to make substantial advances in our understanding of these important elements. Moreover, we are motivated by the prospect of global change and the need to understand the present and future workings of the ocean's biogeochemistry. The GEOTRACES strategy is to measure a broad suite of TEIs to constrain the critical biogeochemical processes that influence their distributions. In addition to these "exotic" substances, more traditional properties, including macronutrients (at micromolar and nanomolar levels), CTD, bio-optical parameters, and carbon system characteristics will be measured. The cruise starts at Line W, a repeat hydrographic section southeast of Cape Cod, extends to Bermuda and subsequently through the North Atlantic oligotrophic subtropical gyre, then transects into the African coast in the northern limb of the coastal upwelling region. From there, the cruise goes northward into the Mediterranean outflow. The station locations shown on the map are for the "fulldepth TEI" stations, and constitute approximately half of the stations to be ultimately occupied.

Figure 1. The proposed 2010 Atlantic GEOTRACES cruise track plotted on dissolved oxygen at 400 m depth. Data from the World Ocean Atlas (Levitus et al., 2005) were plotted using Ocean Data View (courtesy Reiner Schlitzer). [click on the image to view a larger version]

Hydrography, CTD and nutrient measurements will be supported by the Ocean Data Facility (J. Swift) at Scripps Institution of Oceanography and funded through NSF Facilities. They will be providing an additional CTD rosette system along with nephelometer and LADCP. A trace metal clean Go-Flo Rosette and winch will be provided by the group at Old Dominion University (G. Cutter) along with a towed underway pumping system.

The North Atlantic Transect cruise began in 2010 with KN199 leg 4 (station sampling) and leg 5 (underway sampling only) (Figure 2).

KN199-04 Cruise Report (PDF)

Figure 2. The red line shows the cruise track for the first leg of the US Geotraces North Atlantic Transect on the R/V Knorr in October 2010.  The rest of the stations (beginning with 13) will be completed in October-December 2011 on the R/V Knorr (courtesy of Bill Jenkins, Chief Scientist, GNAT first leg). [click on the image to view a larger version]
Atlantic Transect Station location map

The section completion effort resumed again in November 2011 with KN204-01A,B (Figure 3).

KN204-01A,B Cruise Report (PDF)

Figure 3. Station locations occupied on the US Geotraces North Atlantic Transect on the R/V Knorr in November 2011.  [click on the image to view a larger version]
Atlantic Transect/Part 2 Station location map

Data from the North Atlantic Transect cruises are available under the Datasets heading below, and consensus values for the SAFe and North Atlantic GEOTRACES Reference Seawater Samples are available from the GEOTRACES Program Office: Standards and Reference Materials

ADCP data are available from the Currents ADCP group at the University of Hawaii at the links below:
KN199-04   (leg 1 of 2010 cruise; Lisbon to Cape Verde)
KN199-05   (leg 2 of 2010 cruise; Cape Verde to Charleston, NC)
KN204-01A (part 1 of 2011 cruise; Woods Hole, MA to Bermuda)
KN204-01B (part 2 of 2011 cruise; Bermuda to Cape Verde)



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Program Information

U.S. GEOTRACES (U.S. GEOTRACES)


Coverage: Global


GEOTRACES is a SCOR sponsored program; and funding for program infrastructure development is provided by the U.S. National Science Foundation.

GEOTRACES gained momentum following a special symposium, S02: Biogeochemical cycling of trace elements and isotopes in the ocean and applications to constrain contemporary marine processes (GEOSECS II), at a 2003 Goldschmidt meeting convened in Japan. The GEOSECS II acronym referred to the Geochemical Ocean Section Studies To determine full water column distributions of selected trace elements and isotopes, including their concentration, chemical speciation, and physical form, along a sufficient number of sections in each ocean basin to establish the principal relationships between these distributions and with more traditional hydrographic parameters;

* To evaluate the sources, sinks, and internal cycling of these species and thereby characterize more completely the physical, chemical and biological processes regulating their distributions, and the sensitivity of these processes to global change; and

* To understand the processes that control the concentrations of geochemical species used for proxies of the past environment, both in the water column and in the substrates that reflect the water column.

GEOTRACES will be global in scope, consisting of ocean sections complemented by regional process studies. Sections and process studies will combine fieldwork, laboratory experiments and modelling. Beyond realizing the scientific objectives identified above, a natural outcome of this work will be to build a community of marine scientists who understand the processes regulating trace element cycles sufficiently well to exploit this knowledge reliably in future interdisciplinary studies.

Expand "Projects" below for information about and data resulting from individual US GEOTRACES research projects.



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Funding

Funding SourceAward
National Aeronautics & Space Administration (NASA)

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