Expected Datasets from HLY-04-02 Process Cruise
1a. Service Hydrography Measurements (PI: Jim Swift, Dean Stockwell (both onboard), Andreas Muenchow (ADCP); on board team members: Doug Masten, Robert Palomares, Kristin Sanborn, Dan Schuller,Jennifer Sheldon, Dave Huntley, and Dean Stockwell
The SBI Service Measurement Program was represented on HLY0402 by David Huntley (University of Delaware) working on ADCP, Dean Stockwell (University of Alaska, Fairbanks) working on chlorophyll and other pigments, and a six person group from the UCSD Scripps Institution of Oceanography working on CTD/rosette casts and salinity, dissolved oxygen, and nutrient analyses. The six persons were Doug Masten, Robert Palomares, Kristin Sanborn, Dan Schuller, Jennifer Sheldon, and James Swift. This report covers the activities of the SIO group.
Except for the last two sites occupied during HLY0402, which were Video Plankton Recorder-only stations, and a handful of XCTD profiles collected underway, the CTD package was used at every station, with from 1-8 CTD casts per station.
The Healy's Guildline AutoSal salinometer was used to analyze salinity samples. The salinometer ran fine. Bottle salt data quality was excellent, exceeding SBI data quality specifications.
Samples for pigment analyses were drawn from a subset of the rosette bottles at service casts and producitivity casts. The samples were analyzed on board by Dr. Dean Stockwell from the University of Alaska Fairbanks. Six to eight depths per cast were sampled and processed. In addition, samples were processed from some bio-optical stations and for Dr. David Kirchman.
1b. PI: Andreas Muenchow; onboard team member: David A. Huntley, University of Delaware. ADCP
2. Sea ice working group: PI: Rolf Gradinger; onboard team members: Heike Merkel, Sarah Story, and Kazu Tateyama
3. Primary Production, Bio-optics, and Remote Sensing of Ocean Color
PI: Glenn Cota; onboard sampling team: David Ruble, Victoria Hill and Xiaoju Pan
Characterization of
bio-optical properties, the development of relationships between biological
properties of the water column and optical measurements. Collection of
validation points for SeaWiFS and MODIS.
Measurement of primary
productivity using c14 and nutrient uptake (nitrate and ammonium) experiments
at 6 light depths 100%, 50%, 30%, 15%, 5%, 1%. Discrete optical measurements of
absorption of particulate and soluble material, continuous profile measurements
of absorption, attenuation, backscatter, upwelling radiance, and downwelling
irradiance. Samples filtered for later analysis of total suspended material and
pigments (HPLC). Surface measurement of incidence irradiance and surface
reflectance, sunphotometer and ozone.
We experienced setup problems with the new passive optical instruments, this has been resolved, however data for the first week was unobtainable. Due to heavy ice conditions and almost continuous cloud cover there have been no validation points for SeaWiFS or MODIS.
4. Carbon and Nitrogen Cycling Group: PIs: Nick Bates and Dennis Hansell; on-board team members: Christine Pequignet and Jeremy Mathis
5. PI: Dave Kirchman; at sea support: Rex Malmstrom
Samples collected
Profiles coupled with primary production measurements: 14
Net oxygen and respiration measurements: 26
Experiments to examine DOM use: 4
A list of the samples collected to date is shown in Table 1. In addition to these samples, we are collecting data on every CTD cast with a flash fluorometer that provides a measure of the chromophoric component of DOM (CDOM).
7. Biomarkers: PI Rodger Harvey; at sea team member: Laura Belicka
POM samples have been collected at 26 stations in the Bering Strait, Herald Valley, Smith Bay, East Hannah Shoal and Barrow Canyon regions of the western Arctic Ocean, as well as from the Ikpikpuk River, snow-suspended sediments from the Ikpikpuk River and ice rafted sediments from two separate ice stations. At station 031.2, a small boat deployment was used to collect ice rafted sediments, which proved to be an ideal platform for sample collection. One shallow box core was also taken as a test for the deep coring process. Regrowth experiments were also conducted.
8. Evaluation of Shelf-Basin Interaction in the Western Arctic by Use of Radium Isotopes; PI: David Kadko, On-board team member: Mark Stephens
We have collected 55 large volume (200L) water samples from the upper water column (0 to 250m depth). Each sample has been filtered through manganese-coated fibers (which absorbs the radium), and analyzed for initial Radium-224 concentrations.
9. Microzooplankton: biomass, rates of herbivory, and food for mesozooplankton; PI: Ev Sherr and team member Sybille Pluvinage (both onboard)
We completed 10 dilution assays during the Spring 2004 cruise
1) Microzooplankton biomass and analysis of phytoplankton community composition: Samples have been collected at the 6 depths of the primary production assays for 16 primary production casts during the cruise. Three types of samples are collected: for flow cytometric analysis of phytoplankton and heterotrophic bacteria, for epifluorescence microscopy, and for inverted microscopy (Lugol fixed samples).
2) Mesozooplankton grazing experiments: We have sampled the Time 0 and Time Final bottles for the 10 mesozooplankton grazing assays carried out to date on the cruise. These samples will be analysed for change in protist abundance and biomass to evaluate the grazing rate of microzooplankton on heterotrophic protists.
10. Exchange of Plankton and Particles between the Shelf
and Basin; Carin Ashjian (PI) and Stephane Plourde, on-board team
member; Scott Gallager (PI) and Mark Benfield (PI)
11. Mesozooplankton Process Studies; PIs: Carin Ashjian and Robert Campbell; onboard team member: Stephane Plourde
The ultimate goal is to couple these measurements with estimates of total abundance and food availability to describe the role of mesozooplankton in processing carbon (both primary production and microzooplankton) in the two regions. The relative condition of the plankton populations in the two regions also is assessed through measures of carbon and nitrogen content (CN), RNA/DNA (an indicator of metabolic activity), and, for actively reproducing species, egg production rates (EPR).
12. Shelf-Basin Exchange of Large Bodied Zooplankton; PI: Sharon Smith; on-board team members: Peter Lane, Leo Llinas, Tina Senft
Quantify abundances and depth-stratified distributions of pelagic zooplankton over the shelf, slope and basin of the Chukchi and Beaufort seas
MultiNet® Tows: 11
Surface Map Samples: 250
13. PI: Brad Moran; on-board team members: Pat Kelly and Kate Hagstrom
2) Determine POC/234Th ratio values for multiple size fractions of particles, and different types of particles at specific depths
3) Compare 234Th-tracer derived POC fluxes w/ sediment trap derived fluxes of POC.
4) Compare 234Th export from surface water with 234Th accumulation in sediments.
5) Improve 234Th sample resolution from HLY-02-0X using newly developed small volume technique.
14. Water/sediment tracers, sediment metabolism and benthic community structure; PIs: Jackie Grebmeier and Lee Cooper ; on-board team members: Arianne Balsom, Rebecca Pirtle-Levy and Catherine Lalande
The purpose of the benthic component is to investigate pelagic-benthic coupling and carbon cycling in the SBI study area. Methods used include population studies, carbon tracer collections, sediment studies, and water mass tracers. Forty-five stations were occupied during HLY-04-02 for various data collections within our component, both water and sediment samples (Table 1a-c). A sub-sample of water from the surface and chlorophyll max was collected by Dean Stockwell (service cast) and Victoria Hill (productivity cast) and preserved in Lugol’s solution for phytoplankton identification by Dr. Mickle Flint of the Shirshov Institute of Oceanology in Russia as part of our core project. Bottom water was collected from the service CTD for sediment respiration experiments.
Sediments were collected at each station using both a 0.1 m2 van Veen grab and a 0.0133 m2 HAPS benthic corer. Four van Veen grabs were used up to a 500 m depth interval to collect replicate quantitative samples for benthic population studies. Sediment was sieved through 1 mm screens and retained animals preserved in 10% buffered formalin for analysis on land. Sediment collections from both the van Veen and multiple-HAPS corer will be analyzed for chlorophyll pigment content (both fluorometric shipboard and HPLC), total organic carbon and nitrogen content, grain size, and various radioisotopes. Surface sediment were collected in whirl pack bags and frozen. Downcore samples for radioisotope tracers were cut in 1 cm sections to 4 cm depth, 2 cm sections to 20 cm depth, then 4 cm sections to the bottom of the core, sealed in cans, and frozen for laboratory analyses on shore. Measurements of Be-7 and Cs-137 will be made on a high-resolution gamma detector in Tennessee. Large volume surface sediments were also collected in Marinelli beakers for gamma counting. Two additional HAPS cores were collected at each station for sediment metabolism experiments. Overlying water was replaced with bottom water and flux rates determined for oxygen, carbon dioxide and nutrients. Once the experiment was completed, cores were sieved to retain the benthic organisms, which were preserved as outlined above. In addition to sediments collected for our component, we provided sediment to Brad Moran for Th-232 and Pb-210 measurements.
15. Carbon and Nitrogen Isotope Dynamics: Susan Schonberg and Craig Aumack: on-board team members; PI: Ken Dunton
Our objective is to collect biological material from four trophic levels on the Arctic shelf and ocean basin to determine the natural abundance of d13C and d15N.
16. Benthic Carbon Oxidation and Dentirification Group; PI: Allan Devol; onboard team support: Bonnie Chang