Table of Contents

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

SeaBird 911+ bottle processed data.

Standard CTD data collection using the Seabird software.

AR16 CTD Data collection notes.

Casts 1-10 - PAR sensor calibration numbers incorrect in .xmlcon files for each cast #

Casts 1-4 - collected with ar16_initial.xmlcon (data values really wrong)

Casts 5-10 - collected with  ar16_test.xmlcon - data close, but not using the correct cal coefficients for surface par

Casts 11 --> onward collected with ar16.xmlcon - data correct, real calibration numbers.

***** all casts processed with the correct configuration file and calibration coefficients.  The originally collected cast-associated .XMLCON files have not been deleted, but are incorrect as above for the first ten casts.  If reprocessing done, use ar16.xmlcon.*****

APPROPRIATE REPROCESSING CONFIGURATION FILES AND CAST #S.
After cast 11, the associated cast# .xmlcon file is correct.  Also:

ar16_casts1to47.xmlcon
ar16_casts48to60.xmlcon
ar16_casts61plus.xmlcon

can be used for the various cast ranges.

After cast 39 - changed pump on primary side to alleviate sensor clogging issues that showed up in oxygen and conductivity.

Perhaps cast 39 not ended?  The .bl file time did not end until the next cast started.  Replaying the cast shows the bottles firing nevertheless.

Fluorometer (FLNTURTD) started to exhibit strange drift characteristics, trending negative data, and a regular voltage spike pulse around cast 34.   After troubleshooting, the cause was determinted to be failing voltage channels 0-1.  The FLNTURTD (voltage 0-1) and transmissometer (voltage 2-3) cables were swapped on the 9plus CTD voltage channels after cast 47.  This fixed the FLNTURTD instrument.  The transmissometer was not removed from the package until after cast 60.  The intervening transmissometer data should not be trusted.

Late in the cruise, the fluorometer started showing regular spiked data again (no drift).  The problem was determined to be a faulty cable.  As there was a no spare cable aboard for the FLNTURTD, but there was a spare cable on board for the ECO-AFL - the last three casts contain fluorometer data but none from the turbidity channel.

A zipped package of all the raw ctd and bottle data, along with the processed data and notes can be found at this link (172 MB) http://datadocs.bco-dmo.org/docs/Phosphorus_Redox_Cycling/data_docs/ar16.zip.

BCO-DMO Processing:

• Added conventional header with dataset name, PI name, version date.
• Modified parameter names to conform with BCO-DMO naming conventions.
• Reformatted dates to ISO0861 convention.
• Appended latitude/longitude information.
• Appended cast direction information.

NSF Award Abstract:

Redox Cycling of Phosphorus in the Western North Atlantic Ocean
Benjamin Van Mooy
ID: 1536346

Understanding controls on the growth of plankton in the upper ocean, which plays an essential role in the sequestration of carbon dioxide, is an important endeavor for chemical oceanography. Phosphorus is an essential element for marine plankton, and has been a research focus of chemical oceanography for nearly a century. Yet, phosphorus redox cycling rates are almost completely unknown throughout the ocean, and the specific molecular identities of the phosphonates, a form of phosphate, in seawater have defied elucidation. This project will explore and refine entirely new pathways for the biological cycling of phosphorus. This project will support teaching and learning by funding the PhD research of a graduate student, and through the continuation of conducting K-12 classroom laboratory modules and hosting 6-8th grade science fair participants in the investigator's lab.

Phosphorus has never been viewed by oceanographers as an element that actively undergoes chemical redox reactions in the water column, and it was believed to occur only in the +5 valence state, in compounds such as phosphate. However, over the last 17 years, numerous lines of geochemical and genomic information have emerged to show that phosphorus in the +3 valence state (P(+3)), particularly dissolved phosphonate compounds, may play a very important role within open ocean planktonic communities. This is particularly true in oligotrophic gyres such as the Sargasso Sea, where growth of phytoplankton can be limited by the scarcity of phosphate. To better understand these new data, the investigators will design and execute a research program that spans at-sea chemical oceanographic experimentation, state-of-the-art chromatography and mass spectrometry, and novel organic synthesis of 33P-labeled P(+3) compounds. Specifically, they will answer questions about rates of production and consumption of low molecular weight P(+3) compounds, the impact of phosphate availability on the production and consumption of P(+3) compounds, and the groups of phytoplankton that utilize low molecular weight P(+3) compounds. Results of this project have the potential to contribute to the transformation of our understanding of the marine phosphorus cycle.