Table of Contents

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

Processed CTD data from BH15-11.

Related publications:Horner, T. J., Pryer, H. V., Nielsen, S. G., Crockford, P. W., Gauglitz, J. M., Wing, B. A., & Ricketts, R. D. (2017). Pelagic barite precipitation at micromolar ambient sulfate. Nature Communications, 8(1). doi:10.1038/s41467-017-01229-5 

CTD casts were conducted using using a Sea-Bird SBE 9 and SBE 11plus V 5.0. The CTD rosette included: WET Labs WETstar, SBE43 (oxygen), WET Labs CDOM, WET Labs C-Star, and Biospherical/Licor sensors. Data were processed (data conversion, filter, loop edit, bin average, ascii out) using Seasave V 7.23.2. 

Notes:
- These data include both the up and down cast at each station. Because Niskin bottles were fired at certain depths on the upcasts, "nbin" values may be very high at those depths (because the CTD sat at depth for a longer period of time).
- Cast 002.01 was aborted due to a transmissometer issue.

Also see: Cast logs from cruise BH15-11 (PDF).

Example SeaSave processing, from cast 005.01:
# datcnv_date = Aug 28 2015 08:22:28, 7.23.2 [datcnv_vars = 17]
# datcnv_in = C:\Users\Tech\Desktop\Seasave\Raw\CTD_2015\BH15-11\005.01.hex C:\Users\Tech\Desktop\Seasave\Raw\CTD_2015\BH15-11\005.01.XMLCON
# datcnv_skipover = 0
# datcnv_ox_hysteresis_correction = yes
# datcnv_ox_tau_correction = yes
# filter_date = Aug 28 2015 08:23:15, 7.23.2
# filter_in = C:\Users\Tech\Desktop\Seasave\Converted Data\005.01.cnv
# filter_low_pass_tc_A = 0.150
# filter_low_pass_tc_B = 0.150
# filter_low_pass_A_vars = prDM
# filter_low_pass_B_vars =
# loopedit_date = Aug 28 2015 08:26:05, 7.23.2
# loopedit_in = C:\Users\Tech\Desktop\Seasave\Filter\005.01f.cnv
# loopedit_minVelocity = 0.100                                                                                            
# loopedit_surfaceSoak: do not remove                                                                                     
# loopedit_excl_bad_scans = yes
# binavg_date = Aug 28 2015 08:26:48, 7.23.2
# binavg_in = C:\Users\Tech\Desktop\Seasave\Loop Edit\005.01fle.cnv
# 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
# file_type = ascii

BCO-DMO Processing Notes:
- Modified parameters names to conform with BCO-DMO naming conventions;
- Created ISO_DateTime field from dates in CTD .hdr files;
- Added column for "station_name".

NSF Award Abstract:

This proposal to fund a research training cruise on the University of Minnesota's R/V Blue Heron for early career scientists from the Great Lakes basin. The proposed work will have two goals: 1) teach early career lacustrine scientists how to acquire, plan for, and manage cruises aboard UNOLS ships, possibly having some impact on the long-term decrease in requests for ship time on UNOLS ships in general; and 2) expose members of the Great Lakes scientific community, which has an abysmally low submittal rate of proposals to NSF requesting UNOLS ships, to UNOLS and the academic fleet. This project mirrors the successful Chief Scientist training program that Dr. Claire Reimers at Oregon State University has run on ocean-going ships such as the R/V Wecoma, New Horizon and Endeavor.
Intellectual Merit :
The training cruise envisioned herein will allow early career scientists to collect seed data
and test hypotheses for future proposals to NSF.
Broader Impacts :
This proposal intends to educate the next generation of researchers about the capabilities
of UNOLS. This type of outreach between UNOLS and potential users is not only important for
the broader scientific community, but doubly important for the Great Lakes community which
seems resistant to using assets like the UNOLS fleet.

NSF Award Abstract:

Human observations of Earth's climate span only a narrow window of Earth History. Understanding how and why Earth's climate changed before human observations can be overcome through the measurement and interpretation of the chemical composition of marine sediments. Accurate interpretation of these records -- also known as "proxy" records, because they stand in for direct measurements of environmental conditions in the past -- first requires that the behavior of the proxy be properly calibrated against direct observations in modern environments. This project will develop a novel proxy for marine nutrient utilization based on a comprehensive characterization of the chemical composition of particulate organic matter in the Southern Ocean. The formation and export of organic matter in the ocean requires nutrients, consumes carbon, and can influence the global air-sea balance of carbon dioxide. New proxies and calibrations offer novel ways of looking at Earth's climate history and can potentially illuminate interactions within marine ecosystems.

The efficiency of the biological carbon pump depends critically on the availability and utilization of marine nutrients, particularly in the Southern Ocean. However, ambiguity in, and disagreement between current nutrient utilization paleoproxies renders reconstruction of past nutrient regimes uncertain. Cadmium -- a known proxy for phosphate -- offers a means to circumvent many of the known limitations of existing nutrient proxies, but requires a full isotopic characterization before its application. In this project, researchers will trace the stable isotopic composition of cadmium recorded in organic matter using multiple collector inductively coupled plasma mass spectrometry. The researchers will make isotopic measurements across numerous surface nutrient regimes in the Southern Ocean, with a focus on three critical geochemical transitions: the formation of organic carbon at the sea surface, its transit and decomposition through the ocean's interior, and its behavior during burial on the sea floor. This sea surface-to-sea floor calibration will thus comprehensively determine the utility and fidelity of a novel nutrient proxy, allowing a more accurate view of how Earth's climate was related to ocean biogeochemistry in the past.