Scientific Project Description

R/V Kilo Moana Cruise 0625
Cruise Name: EUCFe
Dates: 15 August to 2 October 2006
Chief Scientist: James W. Murray

One of the principle new findings from the 1992 US JGOFS EqPac Process study in the central equatorial Pacific was that iron in the equatorial undercurrent (EUC) was the most important source of iron for driving biological new production and carbon cycling in this region. It has been hypothesized that the source of the iron is from terriginous sources in the vicinity of New Guinea. Hydrothermal and atmospheric aerosol sources are also possible. Our objective in this project is to determine the distributions of iron, manganese and aluminum in a zonal section along the equatorial Pacific.

• 1. Is there really a maximum of iron in the equatorial undercurrent?
• 2. What is its zonal gradient?
• 3. What is its origin?

We plan to conduct a cruise on the R/V Kilo Moana along the equator from 140°W to 145°E. We will occupy stations at 2°N, Eq, 2°S at longitudes where there is a moored ocean climate mooring (TAO-Trident)(140°W, 155°W, 170°W, 180°, 165°E, 156°E and 145°E). Stations will also be occupied on the NE coast of New Ireland and Papua New Guinea in the Bismark Sea. Sampling at each station will consist of Rosette/CTD casts in the upper 1000m. A 24-bottle rosette will be used for nutrient and biological sampling. A 12-bottle trace metal clean rosette will be used for iron and trace metal sampling.

The research being conduced is summarized below:

• Lia Ossiander, Jim Murray, Barbara Paul (Univ. Washington, School of Oceanography)
  Total acid soluble and dissolved iron. Colloidal iron.
• Joe Resing (NOAA Pacific Marine Environmental Lab)
  Dissolved and total acid soluble aluminum and manganese
• Joe Resing and Jim Murray
  Particulate iron, aluminum and manganese.
• Francois Lacan (LEGOS, Toulouse, France)
  Dissolved and particulate stable iron isotopes
• Celia Venchiarutti and Francois Lacan (LEGOS, Toulouse, France)
  Dissolved and particulate neodymium isotopes and rare earth elements (w/ Catherine Jeandel)
• Sharmila Pal and Barbara Paul (Univ. Washington, School of Oceanography)
  Nitrate, nitrite and ammonium by autoanalyzer.
• Adrian Marchetti and Sharmila Pal
  New production using 15N labeled nitrate, ammonium and urea.
• Oguz Yigiterhan (Univ. Connecticut)
  Trace metal composition of plankton (McLain pumps and net tows) Hg concentration and speciation (w/ Bill Fitzgerald, UConn)
• Pierre Dutrieux (Univ. Hawaii)
  Hydrographic and ADCP data
• Lindsey Shank (Central Washington Univ.)
  Atmospheric aerosols: Total composition and solubility of iron (w/ Anna Johansen, CWU)
• Veronica Lance (Duke Univ.)
  Primary productivity and P-I curves
  Spectral absorption by plankton (Quantum Efficiency)
  HPLC Pigments
• Zach Johnson (Univ. Hawaii)
  Phytoplankton genetic diversity
  Photophysiology (Fv/Fm)
  Flow Cytometry
• Cecile Mioni (Univ. Hawaii)
  Expression of iron regulating genes by prochlorococcus and trichodesmium
• John Kirkpatrick (Univ. Washington, School of Oceanography)
  Ammonium oxidizing archaea (w/ Dave Stahl, UW)
• Adrian Marchetti (Univ. Washington, School of Oceanography)
  New and Regenerated Production
  POC/PON
  Phytoplankton composition (microscopy, flow cytometry, RNA/DNA)
• Diana Varela (Univ. Victoria)
  Net and Gross Production of Biogenic Silica
  Biogenic Silica
• Wendy Guo (Univ. Washington, School of Oceanography)
  Winkler oxygen analyses
• John Kirkpatrick and Wendy Guo
  Continuous analyses of oxygen, argon and nitrogen by membrane inlet mass spectrometer (MIMS) (w/ Michael Bender, Princeton Univ.)
• Sophie Bonnet (USC)
  N2 fixation
• AJ Lefevre (Univ. Washington, School of Oceanography )
  Chlorophyll (size fractionated)
  CDOM (colored dissolved organic matter)(w/Norm Nelson, UCSB)
  Dissolved organic matter (DOM)