Table of Contents

• Dataset Description
  • Methods & Sampling
  • Data Processing Description
• Data Files
• Parameters
• Instruments
• Deployments
• Project Information
• Program Information
• Funding

Carbon and Nitrogen concentration from filtered in situ LVP pump samples

Methodology:

Change history: YYMMDD

    070323: data contributed by Ken Buesseler as emailed Excel file 
    070418: added to OCB database by Cyndy Chandler, OCB DMO, (cchandler@whoi.edu) 
            LVP event, date, time, lon and lat agree with cruise event logs; 
            the patch_loc values are not identical to those in the cruise event logs
    070504: adjust parameter names for database consistency
    

PI and OCB DMO Notes: processing notes

SOFeX 2002 Melville and Polar Star cruises

DMO processing notes for in situ LVP data

PI: Ken Buesseler (WHOI)

18 April 2007: Prepared for OCB data system by Cyndy Chandler, OCB DMO (WHOI).

These data are from the filters from in-situ pumps (LVP)
operated by Ken Buesseler's group and used on both the Melville and Polar Star. These data have also been published in:

K. O. Buesseler, J. E. Andrews, S. Pike, M. A. Charette, L. E. Goldson, M. A. Brzezinski, and V. P. Lance, 2005.
"Particle export during the Southern Ocean Iron Experiment (SOFeX)".
Limnol. Oceanogr., 50(1). American Society of Limnology and Oceanography, Inc. pp.311-327.
(download PDF). The sampling and analysis methodology is also described in that publication.

Original Excel file received via email from PI:
copy of original Excel file

The 13C and 15N measurements were done by people in Mark Altabet's lab at UMass Dartmouth. Some notes from David Timothy (School for Marine Science and Technology
University of Massachusetts, Dartmouth, MA) accompanied the original Excel data file:

"These results are NOT blank subtracted! I don't think I included columns for
POC and PN per filter, but you'll see these can be calculated easily (volumes filtered are on the
spreadsheet). I won't be surprised if after blank subtraction there are negative values;
some of the > 54um samples had very low POM."

PI notes

The Buesseler lab "large volume pumps" used on the Melville and Polar Star were of similar design. These casts and data are also reported elsewhere in the OCB database. MULVFS, multiple unit large volume filtration system, another sampling device was only used on the Melville. The LVP's yield about 200-500L per sample, while MULVFS yield on order of 2000L or more. Also, MULVFS casts tend to go deeper, to 1000m, where as LVP samples concentrated on the upper 100-200m.

Contact: Ken Buesseler (WHOI)

DMO processing notes

Melville sampling dates: At some point the sampling dates for the Melville data were put into MS Excel on a Mac system. MS Excel on a Mac uses a different date system from Windows. On a Mac, serial day 1 = Jan 1, 1904 and on Windows, Excel serial day 1 = Jan 1, 1900, and 1900 is an exception to the 4 year leap year rule because it is divisible by 100. When the Excel data file was first ingested into the OCB database, the dates were all off by 4 years and 1 day. However, the actual Excel serial day of 37280.32292 that was entered in the original file is equivalent to Jan 24 2002 07:45:00 - notice the correct year and the time agrees with the event log GMT. The data were copied from the original file and pasted into a new MS Windows Excel file prior to ingestion into the database. This resulted in new sampling dates that matched the cruise's event log except as noted in the next section.

Also, after the date offset (Mac vs. Windows Excel) issue was resolved, the original datafile reported data from station 4 at 08:45 GMT on 25-Jan (according to the MV event log, station 4 was reportedly occupied on 29-Jan, but station 2 had a pump cast on 25-Jan at 08:43). Also, several rows of data were reported from station ? on 29-Jan. The DMO determined this to be station 4. Station 34 data were reported for 11-Feb, but according to the cruise event log, this station was actually done on 12-Feb. The LVP data file was adjusted accordingly to agree with the Melville cruise event log.

The 'patch_loc' field: The SOFeX 'patch_loc' field
is usually one of four abbreviation codes indicating the
sampling location relative to the 'iron fertilized patches'; N indicates North Patch,
S = South Patch, and whether the location is within or outside the patch area or on
the edge of the patch. For the Polar Star cruise, it appears that only the relative in/out
information was recorded. There were two fertilized patches, one north and one south of the
Antarctic Polar Front Zone (APFZ near 61°S) along 170°W. All of the Polar Star sampling events
for which patch_loc is recorded were conducted south of 61°S, implying the south patch.

Before he passed away in 1993, John Martin suggested that an increase in the flow of iron-rich dust to the ocean causes phytoplankton (single celled algae) to grow. The increased photosynthesis removes carbon dioxide from surface waters as the algae create biomass. This carbon dioxide is replaced by carbon dioxide gas that flows into the sea from the atmosphere. Reduced carbon dioxide in the atmosphere cools the planet (CO2 is a greenhouse gas that warms the earth). The results of this work, funded by the National Science Foundation, the Department of Energy, and the US Coast Guard, will be a much better understanding of how biological processes may regulate climate. (see Related Info: Fe cycle)

A direct test of the 'Martin Hypothesis' that trace concentrations of Fe are responsible for phytoplankton's ability to grow by direct experimental addition of Fe to the surface waters. Consequently the distribution of bioavailable Fe in the surface waters determines large geographical areas primary production and the following flux of fixed organic matter to the deep sea. The aim of the SOFeX project is to investigate the effects of iron fertilization on the productivity of the Southern Ocean. The results of this work will contribute significantly to our understanding of important biogeochemical processes which bear directly on the global carbon cycle, atmospheric carbon dioxide concentration, and climate control.

The SOFeX-N and SOFeX-S designations are sometimes used to distinguish between two iron enriched patches - one in low silicate waters north of the polar front (SOFEX-N), and the other in high silicate waters south of the polar front (SOFEX-S). All three ships, Melville (MV), Revelle (RR) and Polar Star (PS), worked in SOFEX-S, but only the Revelle and Melville worked in the SOFeX N patch and shuttled between the two patches.

The Ocean Carbon and Biogeochemistry (OCB) program focuses on the ocean's role as a component of the global Earth system, bringing together research in geochemistry, ocean physics, and ecology that inform on and advance our understanding of ocean biogeochemistry. The overall program goals are to promote, plan, and coordinate collaborative, multidisciplinary research opportunities within the U.S. research community and with international partners. Important OCB-related activities currently include: the Ocean Carbon and Climate Change (OCCC) and the North American Carbon Program (NACP); U.S. contributions to IMBER, SOLAS, CARBOOCEAN; and numerous U.S. single-investigator and medium-size research projects funded by U.S. federal agencies including NASA, NOAA, and NSF.

The scientific mission of OCB is to study the evolving role of the ocean in the global carbon cycle, in the face of environmental variability and change through studies of marine biogeochemical cycles and associated ecosystems.

The overarching OCB science themes include improved understanding and prediction of: 1) oceanic uptake and release of atmospheric CO2 and other greenhouse gases and 2) environmental sensitivities of biogeochemical cycles, marine ecosystems, and interactions between the two.

The OCB Research Priorities (updated January 2012) include: ocean acidification; terrestrial/coastal carbon fluxes and exchanges; climate sensitivities of and change in ecosystem structure and associated impacts on biogeochemical cycles; mesopelagic ecological and biogeochemical interactions; benthic-pelagic feedbacks on biogeochemical cycles; ocean carbon uptake and storage; and expanding low-oxygen conditions in the coastal and open oceans.

The two main objectives of the Iron Synthesis program (SCOR Working Group proposal, 2005), are:
1. Data compilation: assembling a common open-access database of the in situ iron experiments, beginning with the first period (1993-2002; Ironex-1, Ironex-2, SOIREE, EisenEx, SEEDS-1; SOFeX, SERIES) where primary articles have already been published, to be followed by the 2004 experiments where primary articles are now in progress (EIFEX, SEEDS-2; SAGE, FeeP); similarly for the natural fertilizations S.O.JGOFS (1992), CROZEX (2004/2005) and KEOPS (2005).

2. Modeling and data synthesis of specific aspects of two or more such experiments for various topics such as physical mixing, phytoplankton productivity, overall ecosystem functioning, iron chemistry, CO2 budgeting, nutrient uptake ratios, DMS(P) processes, and combinations of these variables and processes.

SCOR Working Group proposal, 2005. "The Legacy of in situ Iron Enrichments: Data Compilation and Modeling".
http://www.scor-int.org/Working_Groups/wg131.htm

See also: SCOR Proceedings Vol. 42 Concepcion, Chile October 2006, pgs: 13-16 2.3.3 Working Group on The Legacy of in situ Iron Enrichments: Data Compilation and Modeling.

The first objective of the Iron Synthesis program involves a data recovery effort aimed at assembling a common, open-access database of data and metadata from a series of in-situ ocean iron fertilization experiments conducted between 1993 and 2005. Initially, funding for this effort is being provided by the Scientific Committee on Oceanic Research (SCOR) and the U.S. National Science Foundation (NSF).

Through the combined efforts of the principal investigators of the individual projects and the staff of Biological and Chemical Oceanography Data Management Office (BCO-DMO), data currently available primarily through individuals, disparate reports and data agencies, and in multiple formats, are being collected and prepared for addition to the BCO-DMO database from which they will be freely available to the community.

As data are contributed to the BCO-DMO office, they are organized into four overlapping categories:
1. Level 1, basic metadata
(e.g., description of project/study, general location, PI(s), participants);
2. Level 2, detailed metadata and basic shipboard data and routine ship's operations
(e.g., CTDs, underway measurements, sampling event logs);
3. Level 3, detailed metadata and data from specialized observations
(e.g., discrete observations, experimental results, rate measurements) and
4. Level 4, remaining datasets
(e.g., highest level of detailed data available from each study).

Collaboration with BCO-DMO staff began in March of 2008 and initial efforts have been directed toward basic project descriptions, levels 1 and 2 metadata and basic data, with detailed and more detailed data files being incorporated as they become available and are processed.

Related file

Program Documentation

The Iron Synthesis Program is funded jointly by the Scientific Committee on Oceanic Research (SCOR) and the U.S. National Science Foundation (NSF).