Table of Contents

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

Processed hydrography data from Metzyme cruise (KM1128) collected using the ship's CTD packages.

These data were published in:
Santoro, A.E., Saito, M.A., Goepfert, T.J., Lamborg, C.H., Dupont, C.L., and G.R. DiTullio. 2017. Thaumarchaeal ecotype distributions across the equatorial Pacific Ocean and their potential roles in nitrification and sinking flux attenuation. Limnology & Oceanography. doi:10.1002/lno.10547

Data were collected using the ship's CTD package (SBE911+). Note that the ship’s first& CTD, used at Station 1, was lost at station 2. A second CTD package was later obtained and used at stations 5-12. (Refer to the 'Problem Report' below for more information.)

Also note that a second CTD package (Trace Metal Rosette (TMR), SEACAT 19+) was also used for sampling at some stations. See the "TMR Hydrography dataset" (https://www.bco-dmo.org/dataset/716685) for these related data.

Note that all raw data are contained in the NODC R2R repository for cruise KM1128. This deposition includes only the processed data. 

Data were processed using SeaBird Data Processing software, version 7.21f.

The processing routine for the first sensor package (file: km1128_001_bin.cnv) utilized the following processing parameters:
# datcnv_skipover = 0
# datcnv_ox_hysteresis_correction = yes
# datcnv_ox_tau_correction = yes
# filter_low_pass_tc_A = 0.150
# filter_low_pass_tc_B = 2.000
# filter_low_pass_A_vars = prDM upoly0 upoly1 xmiss
# filter_low_pass_B_vars =
# alignctd_adv = sbeox0Mm/Kg 2.000                                                                                                                                                                                                   
# loopedit_minVelocity = 0.250                                                                                            
# loopedit_surfaceSoak: minDepth = 2.0, maxDepth = 20, useDeckPress = 0                                                   
# loopedit_excl_bad_scans = yes
# wildedit_pass1_nstd = 2.0
# wildedit_pass2_nstd = 20.0
# wildedit_pass2_mindelta = 0.000e+000
# wildedit_npoint = 100
# wildedit_vars = prDM depSM t090C c0mS/cm sbeox0Mm/Kg upoly0 upoly1 t190C c1mS/cm xmiss
# wildedit_excl_bad_scans = yes

The processing routine for the second sensor package (all other files) utilized the following processing parameters:
# datcnv_skipover = 0
# datcnv_ox_hysteresis_correction = yes
# datcnv_ox_tau_correction = yes
# filter_low_pass_tc_A = 0.150
# filter_low_pass_tc_B = 2.000
# filter_low_pass_A_vars = prDM flSP
# filter_low_pass_B_vars =
# alignctd_adv = sbeox0Mm/Kg 2.000                                                                                                                                                                                                   
# loopedit_minVelocity = 0.250                                                                                            
# loopedit_surfaceSoak: minDepth = 2.0, maxDepth = 20, useDeckPress = 0                                                   
# loopedit_excl_bad_scans = yes
# wildedit_pass1_nstd = 2.0
# wildedit_pass2_nstd = 20.0
# wildedit_pass2_mindelta = 0.000e+000
# wildedit_npoint = 100
# wildedit_vars = prDM depSM t090C sbeox0Mm/Kg flSP c0mS/cm
# wildedit_excl_bad_scans = yes
# binavg_bintype = meters
# binavg_binsize = 1
# binavg_excl_bad_scans = yes
# binavg_skipover = 0
# binavg_surface_bin = no, min = 0.000, max = 0.000, value = 0.000

Problem Report:
The entire rosette, including the CTD sensor package, came free from the hydrowire at Station 2 and was never recovered. A reconstituted, but limited, sensor package was assembled by Station 5. Details given above refer either to the 'first package' (Station 1) or 'second package' (Stations 5-12). Gaps in the dataset were filled using CTD data from the sensor package on the trace metal clean rosette (TMR), deposited as a separate dataset in BCO-DMO.

No ship's CTD data were taken at Station 11.

Surface (0-10 m) oxygen data are suspect.

BCO-DMO Processing:
- modified parameter names to conform with BCO-DMO naming conventions (removed spaces, replaced "/" with underscores);
- replaced blanks (missing data) with "nd";
- converted longitude values from positive to negative to indicate West.

MetZyme project researchers will determine the role of enzymatic activity in the cycling of trace metals. Specifically the research will address the following questions: (1) degradation of sinking particulate organic material in the Tropical North Pacific can be influenced by the ability of microbes to synthesize zinc proteases, which in turn is controlled by the abundance or availability of zinc, and (2) methylation of mercury is controlled, in part, by the activity of cobalt-containing enzymes, and therefore the supply of labile cobalt to the corrinoid-containing enzymes or co-factors responsible for methylation. To attain their goal, they will collect dissolved and particulate samples for trace metals and metalloenzymes from three stations along a biogeochemical gradient in the Tropical North Pacific (along 150 degrees West from 18 degrees North to the equator). Sinking particles from metal clean sediment traps will also be obtained. The samples will also be used to carry out shipboard incubation experiments using amendments of metals, metal-chelators, B12, and proteases to examine the sensitivity and metal limitation of heterotrophic, enzymatic degradation of organic matter within the oceanic "Twilight Zone" (100-500 m). This study will result in a novel metaproteomic/metalloenzyme datasets that should provide insights into the biogeochemical cycling of metals, as well as co-limitation of primary productivity and controls on the export of carbon from the photic zone. In addition to the final data being contributed to BCO-DMO, an online metaproteomic data server will be created so the community has access to the raw data files generated by this research.

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.