29 December 2006 Science Update final report by Brent Steward

Journal

To: Dr. Karl Erb, Director, NSF/OPP

From: Dr. Brent S. Stewart, Chief Scientist

Re: Oden Situation Report 3

Date: 29 December 2006

Oden Southern Ocean Expedition 2006

General

The Swedish Polar IcebreakerAn icebreaker is a special purpose ship or boat designed to move and navigate through ice-covered waters. Oden departed Punta Arenas, Chile, on 12 December 2006 on transit to McMurdo Sound. The objective of this voyage, chartered by the U.S. National Science Foundation, was to position the Oden at the seasonal fast ice edge in McMurdo Sound around 25 December for subsequent opening of the resupply channel through the fast ice to the U.S. McMurdo Research Station. This transit provided a platform of opportunity for scientists from the United States, Sweden, and Chile to conduct limited, collaborative ship-based research in the Bellingshausen, Amundsen, and Ross seas. This expedition is recognized as a kick-off of the 2007- 2009 International Polar YearThe International Polar Year (IPY) is a two year (2007-2009) program of international research and education focused on the Arctic and Antarctic. Click here for more information about IPY..

An extensive education outreach has continued aboard the Oden since launch of the expedition in Punta Arenas. It includes four educators (Ingela Hagstrom, Ute Kaden, Allan Miller, Sandra Williams) who are collaborating with each other on the various national activities and one science journalist. Eight telephone calls and teleconferences have been made to the U.S. and to Sweden since 15 December. Two were PolarTREC tele-conferences with schools in the U.S., three were direct calls to U.S. schools, and three were direct calls to Swedish schools.

The phone calls to the U.S. have now engaged 19 schools throughout the continental U.S. and in Alaska. Phone calls to Chile are planned for just after Christmas. One of the calls to a school in Arlington, U.S. (which has a predominantly Spanish-speaking student body) involved a question and answer session in Spanish with Chilean teacher Sandra Williams and Chilean scientist Veronica Vallejos Marstan on board the Oden.

The science journalist, Daniel Grossman, was interviewed during a satellite phone call by an Australian public radio science show on 22 December and by a U.S. science show on 27 December when Oden arrived at the ice edge in McMurdo Sound. The Oden entered the main pack ice field in the western Amundsen and eastern Ross seas in early morning 23 December. The pack ice concentration increased during the next day and remained extensive, mostly first year ice with patches of second and multi-year ice scattered, until the ship cleared the ice field and into the Ross 2 Polynya on the afternoon of 26 December. Weather continued good to excellent during this period. The Oden then turned south toward Franklin, arrived at the fast ice edge just north of Cape Royds around 1430 hrs on 27 December, and immediately began cutting the ship channel into McMurdo Station. The ship stopped just west of Cape Evans at around 1700 to receive a briefing delegation from McMurdo Station.

All luggage from passengers scheduled to depart the Oden in transit to Christchurch, New Zealand was flown by helicopter into McMurdo around 1900. The briefing delegation departed about an hour later and the Oden continued cutting the shipping channel through the first year ice and then multi-year ice through around midnight. The ship then turned north, cut another swath to the ice edge and then returned south to cut a third swath. The ship was just west of Cape Evans by 0600 hrs on 28 December. PHI helicopter transport operations began at 0830 on 28 December and disembarked all scientists and educators and a couple of Oden crew by 1100.

Most of those personnel then departed McMurdo on a C-17 flight to Christchurch at ca 1630 and arrived in New Zealand at ca 2200. Observations and sampling by the scientific projects continued until early afternoon on 27 December. All gear was then packed and readied to transport to McMurdo later in the day or stored on board for transfer to McMurdo cargo when the Oden docks at the ice pier later.

All science and education operations continued exceptionally well and without interruption. The logistic and moral support for the science projects by the Captain, Officers and Crew of the Polar IcebreakerAn icebreaker is a special purpose ship or boat designed to move and navigate through ice-covered waters. Oden and the staff of the Swedish Polar Research Secretariat continued to be superb. A science meeting and debriefing was held on the Oden on 27 December to organize collaborative plans for analyses, publication, and popular presentation of the observations and data of the several science projects. Another goal was to summarize constructive feedback to the NSF and Swedish Polar Research Secretariat on procedural and substantive logistics relative to the conduct of the science project (to be summarized in Final SitRep).

Science Progress

United States

Diversity, distribution, and relative abundance of marine mammals, penguins, and seabirds from South American to McMurdo Sound during the 2006 transit of the IcebreakerAn icebreaker is a special purpose ship or boat designed to move and navigate through ice-covered waters. Oden. Brent S. Stewart, Ph.D., J.D. (P.I.), Pamela K. Yochem, M.S., D.V.M. (Co-P.I.), William T. Everett, M.S. This project documented the diversity, distribution and relative abundance of pinnipeds, cetaceans, seabirds, and penguins using systematic distance sampling methods during a platform-of-opportunity expedition through a vast but poorly known region of Antarctica. Analyses of observations will correlate ecological data for the airbreathing marine vertebrate fauna with data collected by other ship-based research 3 projects (e.g, biological and physical oceanographic data) and with remotely-sensed data on geostrophic currents, sea ice characteristics, sea level height, and sea-surface temperature and chlorophyll concentration.

The data collected during this expedition will also be compared with regional biological and oceanographic data available from previous studies conducted along the Antarctic Peninsula and recent research expeditions to various areas in the Bellingshausen, Amundsen, and Ross Seas. Moreover, the survey will permit ad-hoc hypothesis generation and testing of the biotic and abiotic factors that affect and determine the diversity, distribution, relative abundance, and community structure of these predators in the Drake PassageStrait, connecting the Atlantic and Pacific oceans between Tierra del Fuego and the South Shetland Islands. Located about 100 mi (160 km) north of the Antarctic Peninsula, it is 600 mi (1,000 km) wide., along the Antarctic Peninsula, and through the Bellingshausen, Amundsen, and Ross seas and provide a foundation and guide for future directed marine scientific research in west Antarctica. Analyses will assess variability in the diversity, distributions and relative abundances of marine mammals, penguins and seabirds relative to variation in ocean climate, ice distribution and concentration, and biological oceanography. The U.S. and the Chilean research teams continued to function as one integrated collaborative research effort for marine mammal and seabird surveys. Near-continuous observations were continued until the Oden exited the pack ice into the Ross Polynya on 27 December. Crabeater seals continued to be common throughout the period and Ross seals were also scattered along the transit track. Weddell seals were seen hauled out as the ship approached and then traveled over the continental shelf. Adelie and emperor penguins were common and minke whales and fin whales were seen on occasion throughout the pack ice. Several killer whales were observed at the ice edge early on 28 December when the Oden was there again briefly during its channel widening efforts
Primary and secondary production measurements along the western Antarctic coastline on the Oden ship of opportunity cruise. Scott Gallager, Ph.D. (P.I.), Emily Miller (Co-P.I.), Cooper Quest. This goal of this project was to make continuous measurements of primary and secondary production to establish a baseline for future cruises and as support for the concurrent marine mammal, sea bird and ice observations. The underway seawater stream was digitally sampled for temperature, salinity, total chlorophyll, pH, dissolved oxygen, CDOM fluorescence, nitrate, phosphate, iron, and zoo and phytoplankton. Discrete samples will also be taken for total carbon, micro-plankton, and pigment structure by HPLC. A second system monitored water nutrients (nitrates, phosphates, silicates, iron) independently.

MODIS remote sensing data will be accumulated for the cruise period to allow cross calibration with in situ pigment data and then cross referenced with underway meteorological data. The overall goal is to understand how the sea ice edge dynamics influence both primary and secondary production especially larval krill dynamics. Measurements of all nutrient elements, except silicates (which consistently increased), remained relatively constant throughout the transit voyage. Another signal in temperature, conductivity, dissolved oxygen, pH, and chlorophyll levels developed 4 when the Oden entered the main Amundsen and Ross pack ice field on 23 December and remained positive until observations ended on 27 December. There was an increase in gelatinous plankton on 25 and 26 December as the Oden transited through the pack ice and then a large increase in chlorophyll on 26 and 27 December as the Oden exited the pack ice into the Ross Polynya.
Sea-ice observations in the Bellingshausen, Amundsen, and Ross seas. Stephen Ackley (P.I.), Hongjie Xie, Ph.D. (Co.P.I.), Bercu Cicek (Co-P.I.) The goal of this project was to collect systematic, comparative observational data on sea ice morphology and distribution as the Polar IcebreakerAn icebreaker is a special purpose ship or boat designed to move and navigate through ice-covered waters. Oden transits through the Bellingshausen, Amundsen and Ross seas. The data collected included ice concentration, ice type, ice thickness, floe size, topology, and snow cover (snow type and thickness) using the ASPeCt protocol standards. Meteorological data will be recorded and summarized and transmitted every six hours to user websites for weather forecasting and navigation assistance. Those data will include sea temperature, air temperature, true wind speed, true window direction, cloud cover (octas), and visibility. The first 4 parameters were obtained directly from the instruments on the Oden (every 5 seconds) and averaged to approximately the same time scale as concurrent ice observations. All collected data will be entered into the ASPeCt software program for detailed statistical analysis and will be shared with the research community through the ASPeCt database.

They will also be used to ground truth and validate satellite-derived geophysical products of sea ice like those from AMSR-E/Aqua, ICESat, and MODIS, and aimed at improving extant algorithms. The Oden travelled through the pack ice zone of the Amundsen and Ross seas from 23 to 26 December. Air and water temperatures declined until the pack ice was exited on 26 December when water temperature increased. While in the pack ice, average hourly sea water temperature was -1.59°C (range -1.16 to -1.80) and average hourly air temperature was -2.64 (range -1.17 to -4.65). The dominant sea ice encountered was first year ice, consisting of mostly very large floes, though multi-year ice and newly formed ice were also present in the ice field. Of 133 ice observations made, the average ice concentration was 50%, ice thickness was 107.8 cm, and snow thickness was 30 cm.
Tracking Southern Ocean temperature fields. Stan Jacobs, Ph.D. (Co-P.I.), Kevin Pedigo. The goal of this project was to map the thermal field in the upper ocean during the spring to summer transition of 2006-07. This work should complement, in part at least, transects that are more commonly occupied across the Drake PassageStrait, connecting the Atlantic and Pacific oceans between Tierra del Fuego and the South Shetland Islands. Located about 100 mi (160 km) north of the Antarctic Peninsula, it is 600 mi (1,000 km) wide. along the WOCE SR3 line south of Tasmania, and between New Zealand and the Ross Sea. It will also provide the scientific coordination and subsequent analysis of XBT casts made in the Southern Ocean from the icebreaker Oden enroute to the SW Ross Sea during the 2006-07 austral summer. A large number of XBTs will be dropped along the transit track starting when the Oden reaches the sea ice edge. The acquired data will be 5 edited, contoured and compared with historical observations from the same region. Particular attention will be paid to temporal and spatial changes in temperature and mixed layer depth versus connections to seasonal and inter-annual variability of the sea ice cover and the state of atmospheric forcing. Measurements will be reported to the appropriate archives, and provided to interested investigators with related Oden projects. We anticipate results that could help to address the nature of warming in the Southern Ocean, along with the effectiveness of icebreakers-of-opportunity to collect these data. Deployment of XBTs ended at 1700 hrs on 26 December with the last of 156 deployed while still in the pack ice. About 10% of the XBTs provided only partial records owing to snagging of the transmission wires on ice before they reached their depth limits.
SOLO float studies of depth-structured temperature and salinity profiles in the Southern Ocean. Breck Owens, Ph.D. (P.I.), Kevin Pedigo. The goal of this project is to deploy six SOLO floats at two locations (near 60º S latitude, and near the ice edge near 150º W longitude as the Oden transits from South America to McMurdo Station. These floats measure temperature and salinity at particular depths. They will record profiles of sea water temperature and salinity to approximately 1800 dbars (or 1800 m) every 10 days. Once the float is deployed, it immediately descends to its maximum depth, takes a profile, ascends back to the surface and then sends the data back using satellite communications. After sending the data back the first time, the float descends again to about 1000 m, drifts for about nine days, descends to 1800 and records a profile as it ascends to the surface and transmits the data to orbiting satellites. Each float will repeat this latter cycle until the batteries expire about four to five years later. The first three floats to be deployed (at 59DegS, 60DegS, 61DegS) transmit data via the Service Argos Data Collection and Location System (DCLS) while at the sea surface for about eight hours. The second set of three floats use the Global Positioning System (GPSA Global Positioning System (GPS) is a satellite-based navigation system used to track the location or position of objects on the Earth’s surface.) constellation of satellites calculate geographic location of the float when at the surface and the Iridium satellite system to transmit data back to users. The data is processed within a few hours after it is received and then transferred to the GTS data system that distributes the meteorological and oceanographic data to all weather and climate prediction centers around the world. The data are also sent to the Argo Global Data Acquisition Centers (GDACs) and are available at these websites: http://www.coriolis.eu.org//cdc/argo.htm and http://www.usgodae.org/cgi-bin/argo_select.pl The last (5th of 6; 2d SOLO failed before deployment) of the SOLO floats was deployed on 22 December. 6 Sweden
Variability of the carbon dioxide system, oxygen and biogeochemical processes in the surface water and the Marginal Ice Zone of the Southern Ocean. Agneta Fransson, Ph.D. (P.I.). The aim of this project was to document the variability of the carbon dioxide (CO2) system in the surface waters of the Southern Ocean and the biogeochemical processes that may drive this system during the productive summer season. The ocean fronts, the marginal ice zone, and the ice edge are interesting areas to study because of relatively high biological production, hence high biological CO2 uptake. Due to the seaice cover, with sea-ice production and melting, a variable environment is created for biological production and CO2 fluxes. The CO2 gas exchange between sea and atmosphere (sea-air) is estimated and related to the physical and biological characteristics of the surface water. Moreover, the importance of sea ice for CO2 fluxes in the sea-ice-air interface will be investigated. The project will use on-line, highfrequency measurements of surface water partial pressure of CO2 (pCO2), dissolved oxygen, chlorophyll fluorescence, salinity and temperature. Samples for total dissolved inorganic carbon (DIC), total alkalinity (AT) and nutrients (phosphate, nitrate, silicate) will be collected and measured on shore. There were increases in pCO2 and oxygen and correlative peaks in Chl-a when the Oden entered the pack ice on 23 December, similar to patterns observed on 18 December. A substantial increase in Chl-a was detected as the Oden entered and transited the Ross Polynya. Levels remained high until data collection ended on 27 December. This appeared to indicate a substantial, but young, phytoplankton bloom.
Ship-based observations and remotely sensed data for the evaluation of the carbon dioxide system along the Marginal Ice Zone in the Southern Ocean. Melissa Chierici, Ph.D. (P.I.). The aim of this project was to use ship-based observations jointly with remotely sensed data to better assess the magnitude and variability of the biogeochemical processes that may drive the oceanic carbon dioxide system in the marginal ice zone in the Southern Ocean. Remotely sensed data provide an unprecedented sampling coverage and satellite borne sensors provides near synoptic global coverage of parameters like wind speed over the ocean, sea surface temperature and chlorophyll concentration. On-line high-frequency measurements of pCO2, oxygen, sea surface temperature, salinity, chlorophyll fluorescence and nutrient data will be compared with remotely sensed chlorophyll and temperature to evaluate algorithms for the quantification of pCO2 and the air-sea CO2 flux. Chile
Records of Antarctic marine vertebrates between Magellan Strait and McMurdo Station. Veronica Vallejos Marsten, M.S. (P.I.). 7 This goal of this project is to document the occurrence of marine mammals and seabirds in the waters of western Antarctica from South America to McMurdo Station, and particularly from Cape Horn to 90ºW longitude, by collaborating with a team of researchers from the United Sates of America who will be collecting similar systematic data. The Chilean and U.S. research teams continued to function as one integrated collaborative research effort for marine mammal and seabird surveys (see summary above).
Persistent organic pollutants in remote areas: Pesticide residues in the Southern Ocean. Victor Hernandez-S. (P.I.) and Henrik Kylin (Co-P.I.) The goal of this study was to collect samples of organic compound pollutants along the transit of the Oden through relatively unvisited areas where anthropogenic impact is presumed to be minor to help understand these pollutants may be transported from warm to cold areas. There are few data on persistent organic pollutants (POPs) in seawater from the Southern Ocean. In contrast to the Arctic, data from the Antarctic is too sparse to allow temporal analyses. Comparative data from both areas are needed to develop and check models of the global distribution of these pollutants. There has been only one other campaign in West Antarctic to sample for these pollutants, in the Australian sector in 1989-1990. Considering the latest sampling on the African side on these latitudes, we would expect 10-50 pg L-1 of HCHs in the stations sampled in this track, before the convergence point, between long. 77°21' W and 61°19' S Latitude through, perhaps, 170° W Longitude and 75° S Latitude in Ross Sea.

The sampling effort during the Oden Southern Ocean Expedition will, therefore, fill a gap in knowledge about the extent of pollution in Antarctic systems. This project will collected measurements of hexachlorohexanes (HCH) residues in Southern Ocean surface waters during the transit of the Oden from South America to McMurdo Station. Solid phase extraction (SPE) will be used to pre-concentrate larger quantities of water and then to dialyze and analyze them using gas chromatography to qualify and quantify their presence in these relatively poorly known areas. Water samples collection continued through 26 December via a fresh seawater inlet at the bottom of the ship, at ca. 8 m below the surface. This water was extracted by means of a SPE with ENV+ cartridges (Polystyrene di-vinylbenzene copolymer) in volumes of 10 L per sample. The samples are pulled by the cartridge with a peristaltic pump from a pressurized steel can and are being filtered with a Whatman filter, 47 mm diam., nominal cutoff 0,47 ?m (see summary of data in Table 1). Blank samples were run with de-ionized water. The collection cartridges will be analyzed in labs in Chile and in Sweden during the next several months.