SCICEX Projects to Date

Title: Arctic Ocean Methane
PI(s): Keith Kvenvolden, USGS
Point of Contact: Keith Kvenvolden
SCICEX Cruise: 1993
Abstract: In this project, we have shown that methane a "greenhouse gas" is present Throughout the arctic ocean. In surveys conducted mainly between 120 and 230 degrees longitude using the u.s. navy nuclear submarine Pargo (1993) And the canadian ice breaker Louis S. St. Laurent (1994), we showed that Methane is present in water beneath the permanent ice at variable Concentrations near the surface that usually exceed the atmospheric Equilibrium concentrations of about 4 nanomolar by factors of about 1.3 to 4. Methane concentrations decrease with depth. 

Title: Tritium/He-3 results from SCICEX 93 (PARGO)
PI: Peter Schlosser
Point of Contact: Peter Schlosser
SCICEX Cruise: 1993
Abstract: Tritium and its radioactive decay product, He-3, are used as transient tracers to study the pathways of water masses that have recently been in contact with the atmosphere. Additionally, these tracers provide mean residence times and deep water formation rates. The main goal of the PARGO 1993 tritium/He-3 program was to test if high-quality tritium/He-3 samples can be collected during a submarine cruise.

Specifically, we wanted to see if surface stations can be carried out within a reasonable degree of effort. The sampling program was performed in an ad-hoc fashion and supported by ONR through ANWAP (Arctic Nuclear Waste Assessment Program). The results from this cruise demonstrated that high-quality tritium/He-3 data can be obtained from submarines by occupying surface stations.

The results are posted on our WWW site:

Title: Chemical Tracers of Pacific Water in the Arctic Ocean
PI(s): Ted DeLaca, Peter McRoy
Point of Contact: Peter McRoy
SCICEX Cruise: 1993

Title: Geophysical and Geochemical Studies of the Arctic
PI(s): Bill Smethie, LDEO
Point of Contact: Bill Smethie
SCICEX Cruise: 1993
Abstract: We obtained about 120 CFC samples from the SCICEX 93 cruise. These samples were collected at surface stations using 10-liter Niskin bottles. Water samples were drawn from the Niskin bottles into 200cc glass syringes and these syringes were taken inside the submarine where the water was transferred to glass ampoules and flame sealed. We bootlegged the analysis of the samples at Lamont. The results were mixed. Many of the samples for CFC-11 were good, but all of the samples were contaminated with CFC-12. The reason was that the atmosphere inside the submarine contains extremely high levels of CFC-12 (one million greater than outside air) due to leaky air conditioning and refrigration systems and these substances are not scrubbed out of the air. We had not anticipated this, but in hindsight it is not surprising since the air inside the submarine is not constantly being renewed with fresh air and even a small leak of CFCs can result in high levels under these conditions. There have been no publications based on CFC results from this cruise nor will there be. The good CFC-11 analyses gave us encouragement that good quality CFC samples could be collected from a submarine if precautions were taken to prevent contamination with the submarine air.

Title: Arctic Oceanographic Buoy Deployment, CTD/XCP Section and Physical Oceanography Equipment for Use During Arctic Science
PI(s): Jamie Morison, University of Washington and Roger Colony
Point of Contact: Jamie Morrison
SCICEX Cruise: 1993
Abstract: During the cruise we made surfaced CTD stations, launched SSXCTD, mounted a SeaCat CTD in the ship's sail for underway measurements, dropped EXpendable Current Probes (XCP), and installed Polar Ocean Profile hydrographic buoys. This effort has yielded an extensive synoptic picture of the hydrography of the upper Arctic Ocean. The temperature and salinity sections along the cruise track of the Pargo as measured with the surface CTD and SSXCTD illustrates that a much greater portion of the Arctic Ocean is now dominated by water with an Atlantic Ocean origin than was previously found. The -1°C Bering Sea halocline water of the western Arctic is bounded by a strong front over the Alpha and Mendeleyev Ridges. In the past this boundary has lain over the Lomonosov Ridge. Warm cores of Atlantic water are seen recirculating over the Lomonosov and Mendeleyev Ridges and moving back towards Fram Strait. High salinity water of the upper halocline appears at the surface in the Makarov Basin and over the east longitude portion of the Lomonosov Ridge. Salinities in this area are 2.5 psu greater than reported in Gorshkov (1983) and the temperatures are 1°C greater in the region of the warm core. These changes are much greater than can be explained by instrumental error in the climatology and suggest a major change in the state of the upper Arctic Ocean. We have compared the upper ocean circulation with atmospheric pressure and ice drift data and find a correlation between the changes in these parameters and the changes observed in the ocean. Consequently, we believe the change in ocean circulation is driven by a change in atmospheric forcing. The wind forcing drives the circulation change by Ekman pumping and subsequent baroclinic adjustment.

Title: Geophysical Study of Chukchi Borderland and Lomonosov and Alpha Ridges
PI(s): Bernie Coakley and James Cochran, LDEO
Point of Contact: Bernard J Coakley
SCICEX Cruise: 1995
Abstract: This award supports a geophysical survey from a nuclear submarine during operation SCICEX-95 cruise to the Arctic Ocean. The survey will result in a comprehensive map of bathymetry and gravity of the Chukchi Borderland and portions of the Lomonosov Ridge, Makarov Basin and Mendeleev Ridge. These areas are out of the normal operating range of aerogeophysics platforms and data from the region that are available to western scientists are extremely sparse. The proposed survey is designed to test current hypotheses of the geologic structure and tectonic development of the main geographic features of the region. Whether the hypotheses prove to be true or not, the data will fill a conspicuous gap in the geophysical data coverage in the Arctic Ocean Basin. Hence, the data collected will be valuable to determining the geologic and tectonic structure of the region and, in turn, will also be useful for evaluating tectonic models for the development of the region.

Title: Identification and quantification of rafted thick sea ice
PI(s): Max Coon and Skip Echert, Northwest Research Assoc.
Point of Contact: Max Coon,
SCICEX Cruise: 1995
Abstract: The goal of the NWRA study of the 1995 data was to determine the frequency of occurrence of thick, deformed pack ice that has resulted from rafting events, not ridging events. It was not possible to grab a frame from the video recording because of electrical interference in the recording (we understand that this interference has since been eliminated). We identified rafted ice by finding the keels of serpentine "ridges."

Our findings from side-scan sonar imagery are the following:

In an effort to understand the conditions under which thick ice could raft, we developed a model. In the model, first-year ice is separated by a refrozen lead. as the lead begins to close, the ice in the lead has failed and has piled up along the edge of the thick, first-year ice. The thick, first-year ice is fractured by the weight of the ice from the lead that has piled on top. The fracture is parallel to the edge of the floe. Further closing causes the thick ice to slide up and over the "ramp" caused by the fractured thick ice. We have done calculations of the amount of ice required from the lead to cause the rafting of ice of various thicknesses. To raft ice about 1-1/2 meters thick, only the modest amount of 20 meters of 10cm ice would be needed in the lead to cause the rafting.

Title: A Multidisciplinary Analysis of Shelf-Derived Carbon Dispersal Within the Arctic Basins, as Sampled by Submarine
PI(s): Terry Whitledge and R. Benner, Univ. Texas
Point of Contact: Terry E Whitledge
SCICEX Cruise: 1995
Abstract: Dissolved organic carbon (DOC) is the major reservoir of organic carbon in the Arctic Ocean, and as such this reservoir may also serve as an important sink for atmospheric carbon dioxide. Characterization of the processes controlling the concentrations and fates of DOC is therefore critical for gaining a quantitative understanding of the Arctic Ocean carbon cycle. During a U.S. Navy submarine cruise in March-May 1995 along the shelf breaks of the Beaufort, Chukchi, East Siberian, and Laptev Seas, approximately 1,000 samples will be collected and analyzed for concentrations of nutrients, DOC, and dissolved inorganic carbon (DIC). Approximately 100 water samples will be analyzed for dissolved oxygen, alkalinity, and chlorophyll/phaeopigments during the cruise track. These data will be used to determine the sources of DOC to the various regions, the rates of microbial remineralization processes, and the coupling between nitrogen and carbon cycling.

Title: CTD observations of the Arctic ocean halocline
PI(s): Mike Steele, Knut Aagard, and Jamie Morison, University of Washington
Point of Contact: Tim Boyd
SCICEX Cruise: 1995
Abstract: We deployed a variety of CTD instruments designed to measure temperature and salinity in the upper few hundred meters of the Arctic Ocean during SCICEX'95. These included: (1) underway CTD observations at the cruising depth of the sub, (2) expendable XCTD's deployed through the torpedo tubes while submerged, and (3) surface CTD's deployed through a hole in the sea ice. Results indicate that substantial changes in the halocline have occurred during the course of the 1990's and also relative to the climatology of the previous 40 years.

Title: An integrated tracer study of Arctic Ocean surface and halocline waters
PI(s): Alan Volpe and Bradley Esseer, Lawrence Livermore National Labs
Point of Contact: Alan Volpe,
SCICEX Cruise: 1995
Abstract: We describe chemical data for water samples collected during the 1995 SCICEX Arctic cruise aboard the USS Cavalla. The purpose of the study is to measure a complementary suite of chemical tracers in Artic surface mixed layer, halocline and Atlantic-layer waters to constrain water mass mixing and transport. The water samples are principally from sites in the Western Arctic Canadian Basin. These include 24 sites throughout the basin and across the Lomonosov Ridge using the submarine intake line at 134m depth, and five ice cast stations (7-800m) from the Beaufort Sea near McKenzie R., the shelf break off the Chukchi and East Siberian Sea, the Makarov Basin and Alpha Ridge.

The chemical data include salinity, trace elements (Ba, Sr, Mo), transition metals (Ni, Cu, Zn) heavy metals (Cd, Pb and U) , rare earth elements (REE), oxygen isotopes 16O/18O, tritium 3H, and radiocarbon 14C. This integrated suite of tracers clearly delineate components in the water mass assemblies. Topics that will be discussed include the freshwater balance and Pacific component in upper-layer waters of the Western Arctic, and geochemical and isotopic tracers of the Atlantic/Pacific water mass front near the Lomonosov Ridge.

Title: Meteorological buoy deployment for the United States Interagency Arctic Buoy Program (USIABP)
PI(s): Dave Benner, National Ice Center
Point of Contact: Dave Benner,
SCICEX Cruise: 1995, 1996
Abstract: The objective of the USIABP is to establish and maintain a network of drifting buoys in the Arctic Ocean with which to collect data for real-time operations and meteorological and oceanographic research. Data are used to generate and monitor synoptic-scale fields of surface atmospheric pressure, surface air temperature and ice motion throughout the Arctic basin. The USIABP is funded through the collective contributions of the Office of Naval Research (ONR), National Aeronautic Space Administration (NASA), National Science Foundation (NSF), U.S. Navy (USN) and the National Oceanic Atmospheric Administration (NOAA). Overall management of the USIABP is provided by the National Ice Center (NIC) while the production and quality of a historical data base is provided by the Polar Science Center of the University of Washington. Significant achievements over the past year include: the design and deployment of a new buoy design with environmental monitoring capabilities, the coordination of buoy deployment sites with International Arctic Buoy Program (IABP) partners and the production of a new 12 hourly 2 meter air temperature field product. The USIABP has also worked closely with the SHEBA ice camp experiment by providing meteorological buoys for the mesoscale monitoring of meteorological fields.

Title: Radionuclide and organic tracer studies in the Arctic Ocean
PI(s): J. N. Smith, Barry Hargrave, Bedford Institute, and L. K. Kilius, U. Toronto (deceased)
Point of Contact: John Norton Smith
SCICEX Cruise: 1995, 1996, 1997
Abstract: This program focuses on the use of radionuclide and organic contaminants as tracers to determine water circulation time scales and current levels of persistent pollutants in water and biota of the Arctic Ocean. The radionuclide component of the program involves measurements of 137Cs and 129I on seawater samples collected through the hull of the vessel while the submarine is underway and from the ice surface or deck of the vessel following a submarine surfacing. 137Cs and 129I have been released in large quantities from European reprocessing plants at Sellafield (UK) and La Hague (France) during the past 30 y and their distribution in the Arctic Ocean provides information on rates of contaminant transport from European coastal waters. Results from the 1995 USS Cavalla cruise reveal a well-defined "front", in surface mixed layer and halocline water, between Atlantic-origin water having high 129I levels (> 100 x 107 at/l) and Pacific-origin water labeled solely by fallout levels (< 5 x 107 at/l), which is aligned along the Mendelyev Ridge. The 129I and 137Cs data are consistent with transit times of 5-7 y for the passage of Atlantic halocline water from the Norwegian Coastal Current to the Makarov Basin. Results from the 1996 USS Pogy cruise, collected on a transect from the Lomonosov Ridge through the Canada Basin to the Beaufort Sea, show very low 129I levels (< 5 x 107 at/l) in halocline and Atlantic layer water over the Alpha Ridge and Northern Canada Basin, reflecting the extremely low ventilation rates for intermediate waters in this region. However, higher 129I levels were measured in Atlantic water in the Central Canada Basin reflecting the more efficient ventilation of the basin interior which probably occurs by lateral transport from boundary currents flowing over the continental margins.

In the organic contaminant component of this program, scavenging amphipods have been collected from water depths in excess of 3500 m in the Canada Basin using a specially designed sampling system developed for submarine cruises. Measurements of chlorinated hydrocarbons (agricultural pesticides and industrial PCBs) have been conducted on these samples to provide information on their spatial and temporal distributions in the Arctic Ocean, a region for which there is very little data. The amphipod, Eurythenes gryllus has been used as a sentinel organism for monitoring arctic marine contaminants. Results from the USS Pogy cruise indicate that the same organo-chlorine pesticides measured in Eurythenes from the Canada Basin in 1983 were still present in 1996 and that contaminant levels show a small decline, possibly associated with trends in the overlying water column. Strategies for future SCICEX cruises focus on exploiting the flexibility of the submarines to document the time-varying radionuclide and organic contaminant contaminant signals in sparsely sampled regions of the Arctic Ocean and to use these data to further understand arctic circulation and tracer transport processes.

Title: Submarine profiling of Arctic Properties: Ice Profiles and Sound Speed
PI(s): Ruth Keenan, Peter Mikhalevsky, SAIC
Point of Contact: Peter Mikhalevsky,
SCICEX Cruise: 1995, 1996

Title: Submarine profiling of Arctic Properties: Temperature, salinity, ice draft
PI(s): Peter Mikhalevsky, Ruth Keenan, SAIC
Point of Contact: Peter Mikhalevsky,
SCICEX Cruise: 1997

Title: Recent hydrographic variability of the upper Arctic Ocean derived from submarine based samples
PI(s): Peter Mikhalevsky and Mary Sue Mustafa, SAIC
Point of Contact: Peter Mikhalevsky,
SCICEX Cruise: 1998
Abstract: Analysis of the four SCICEX transarctic CTD transects and ice roughness measurements collected during SCICEX-95 (spring), -96 (fall), and 97 (summer) are helping establish understanding of the variations in the extent, path, and rate of spreading of recently observed warm anomolies in the Atlantic Intermediate Layer and the movement of water mass boundaries in the upper Arctic Ocean water column. In addition sound speed derived from the CTD measurements and ice roughness measurements are being used as ground truth for synoptic acoustic measurements. Acoustic thermometry in the Arctic Ocean has demonstrated the ability to provide synoptic measurements of ocean temperature change and possibly sea ice thickness, roughness and extent. Examination of the Transarctic Acoustic Propagation (TAP) experiment acoustic signal's modal structure has indicated warming of the Atlantic water by an average of 0.2 to 0.4C relative to pre-1990 climatology. SCICEX Transarctic transect measurements are consistent with these observations. The acoustic thermometry signatures derived from the SCICEX water column measurements are being used in the planning of the Arctic Climate Observations using Underwater Sound (ACOUS) program under the auspices of the Gore-Chernomyridin Commission under a bilateral agreement between the United States and Russia.

Repeated drops of submarine launched XCTD samples with matched surface station CTD and XBT drops helped us to suggest probe design modifications and to establish more robust fall rate coefficients; thus higher quality probes and data for future SCICEX operations.

Title: Tracing riverine inputs and ventilation processes of the upper Arctic by means of submarine mounted on-line chemical sensors
PI(s): Kelly Falkner and Gary Klinkhammer, Oregon State University
Point of Contact: K. Kenison Falkner,
SCICEX Cruise: 1993, 1995, 1996, 1997
Abstract: The SCICEX platform has served as a ship of opportunity for our sampling program aimed at tracking Arctic river waters by geochemical means. We have primarily conducted Ba sampling from the submarines as we learned early on that this element shows little susceptibility to contamination through the intake and it can be uniquely applied to delineating the influence of North American versus Eurasian rivers within the Arctic. The submarine has provided critical samples from regions otherwise inaccessible to us. In 1996, our program was expanded to examine continuously recorded fluorescence of terrestrially derived dissolved organic carbon as detected by a hull-mounted zero-angle photon spectrometer. We are presently combining our data sets to gain a first order understanding of the distribution of terrestrial DOC in the Arctic interior. An initial presentation of the results will be made by Ph.D. student C. K. Guay at the Ocean Sciences meeting in February, 1998.

Title: Diversity and Metabolic Capabilities of Arctic Bacterial Communities
PI(s): James T. Hollibaugh, Univ. Georgia
Point of Contact: James T. Hollibaugh
SCICEX Cruise: 1995, 1996, 1997, 1998
Abstract: The proposed studies investigate the distribution of key properties - abundance, community composition and community metabolic capabilities of bacterial communities in the Arctic Ocean. We are examining the patterns of spatial and temporal variation of these properties and attempting to relate them to sources of organic matter fueling heterotrophic production.

The investigation is being conducted using samples collected from a submarine dedicated to Arctic oceanography. Samples were collected in August 1993, April 1995, October 1996, September 1997 and will be collected in the summer of 1998. Some analyses are conducted in the field, but most are completed in my laboratory after the cruise. Community composition is being analyzed using a method developed in my laboratory that is based on separating partial sequences of the 16S rRNA gene. Community metabolic capability is being assessed by the ability of bacteria to grow heterotrophically on a battery of 95 different sole C sources. Bacterioplankton abundance is determined by epifluorescence microscopy.

The results of these measurements will be to broaden our description of the seasonal variation of these microbiological properties over a wide area of the Arctic Ocean basin. We will also compare our data with comparable data collected by colleagues participating in similar studies in the Southern Ocean.

Title: Fluxes of dissolved inorganic, dissolved organic and particulate carbon associated with water masses of the Arctic Ocean based on samples from the 1996 U.S.N. submarine cruise
PI(s): Ray Sambrotto, LDEO
Point of Contact: Raymond Sambrotto,
SCICEX Cruise: 1996
Abstract: The recent use of the U.S. Navy's atomic submarines for non-military scientific exploration in the Arctic has opened a new dimension in the oceanography of the least sampled ocean basins. Samples obtained from the first such cruise added significant detailed to the 3-dimensional analysis of dissolved inorganic carbon (DIC) in the Arctic ocean, a region that may play a much greater role in the carbon dynamics of the world ocean than has been appreciated. Based on samples brought back from the 1996 science cruise, the proposed project will make additional measurements of DIC and add new and critical measurements of dissolved organic carbon (DOC) and particulate carbon (PC). These measurements will quantify the inorganic and organic carbon pools associated with waters in the Canada, Makarov, Amundsen and Nansen basins as well as shelf and upper slope waters of the Chukchi region that appear to be the site of entry for a huge amount of carbon to the upper halocline of adjacent waters. The fall timing of the 96 cruise is ideal for the latter measurements because it coincides with the end of the productive season and the beginning of the cooling and sinking of shelf waters into adjacent basins. Spatial changes in the carbon pools will be analyzed with respect to geochemical tracer data such as tritium and 3He collected from the submarine and other Arctic cruises to estimate the rates of change associated with each pool. Such rates are critical for understanding the Arctic's role in the carbon cycle at the world ocean and global scale. As one of the atmospheric constituents that is prominent in the heat budget of the lower atmosphere, carbon dioxide has received increasing scrutiny to assess the non-man induced factors that influence its abundance. The Arctic Ocean is currently poorly characterized in this respect but is a potentially important link in the dynamics of the ocean's carbon cycle. First order questions include the size of the carbon reservoirs associated with the unique water masses of the Arctic, the water mass formation rates, and the changes, if any, that can be expected in these cold reservoirs if climate change brings about a warming in this region.

Title: The Entry of Bering Sea Water into the Canadian Basin Gyre
PI(s): Tom Hopkins, North Carolina State University
Point of Contact: Tom Hopkins,
SCICEX Cruise: 1996
Abstract: The main observational task of the project was to locate the route of the BSW from its point of entry near Herald Canyon to its destination in the center of the Canadian Basin (CB). This involved a mapping of the BSW in the area of the Chukchi Borderland and observing its structure within the CB. Primary data acquisition was by means of expendable Conductivity, Temperature and Pressure (XCTD) casts, surface CTD casts, hull-mounted, online CTDs, and online water sampling. The physical parameters of interest were temperature, salinity, density and oxygen, nutrients and other chemical tracers. This project also undertook the responsibility of acquisition, pre-processing, processing, archiving and distributing the hydrographic data, except for the post-cruise processing of the XCTDs, which was done by Co-PIs from Science Applications International Corporation (SAIC) and the Lamont Doherty Earth Observatory (LDEO). The types of interpretive objectives being addressed with the data set are: 1) the water-mass distribution of the BSW by characterizing the input water type, mapping the vertical and horizontal distributions of the BSW, determining its mixing history as a function of space, and estimating the transport contributions to the CB Gyre; 2) the adjusted geostrophic circulation and transports by using the steric-height method through an extrapolated extension of the observed density field to the bottom and along the bathymetric fall lines to the deepest common point in the Basin by using GDEM density data; 3) the fresh-water content by determining the Chukchi Sea reference salinity and vertically integrating for the fresh-water content of all stations and mapping its distribution over the Chukchi Borderland and in the center of the CB; 4) the contribution of the Lower Halocline Water (LHW) to the CB Halocline by using both physical and chemical parameters to separate the water properties of the BSW from the LHW by comparing water-types, nutrient ratios and other information; and 5) the water mass distribution of the Polar Atlantic Intermediate Water by tracing its water type within the observed data set, conducting water-mass mixing ratios between it and the BSW and LHW, and estimating the heat and salt requirements to sustain the CB halocline.

Title: Arctic Gravity and Bathymetric Data Acquisition Over the Arctic Mid-Ocean Ridge and the Lomonosov Ridge
PI(s): Bernie Coakley and James Cochran, LDEO
Point of Contact: Bernard J Coakley
SCICEX Cruise: 1996
Abstract: Funds are requested to cover the costs of gravity and bathymetry data acquisition in the Arctic Ocean for a study of the Arctic Mid Ocean Ridge (AMOR) and the adjacent sliver of continental crust, the Lomonosov Ridge. In concert with the physical oceanographic program, we would like to collect additional long bathymetric and gravity anomaly profiles across the combined Lomonosov Ridge and AMOR. This data, combined with the collected on previous submarine science cruises, will permit the construction of regional scale maps across much of the basin within the operational area. The advance of plate tectonics into the Arctic Ocean basin has reached only to the Lomonosov Ridge. The Arctic Mid Ocean Ridge is the northern extension of the Mid Atlantic Ridge. It is perhaps the slowest spreading ridge on earth. Propagation of the AMOR into the Arctic Ocean separated the Lomonosov Ridge from the northern edge of Eurasia beginning at about 58Ma. This separation has continued up until the present time. Maps produced during this study will be used to define transverse structures in the ridge (the geometry of half graben bounding faults and transfer zones) and the morphology of the AMOR. The regional lines will also be useful for studies of isostatic compensation of both the Lomonosov Ridge and the AMOR as well as defining he transition from the Lomonosov Ridge to the adjacent enigmatic Alpha-Mendeleev Ridge.

Title: Submarine Cruise 1996: Tracer Studies of the Large Scale Circulation of the Upper Waters in the Canadian Basin
PI(s): Bill Smethie and Peter Schlosser, LDEO
Point of Contact: P. Schlosser,
SCICEX Cruise: 1996, 1997
Abstract: Originally, we received NSF funds for collection of about 200 tritium/He-3, about 300 CFC, and about 200 O-18 samples during the 1996 SCICEX cruise (POGY). Due to logistical constraints, the sample collection was spread out over two years. During the first year (POGY) we collected about 150 tritium/He-3, 294 O-18, and 103 CFC samples, mainly along a section extending through the center of the Canadian Basin between about 88N, 44W (Lomonosov Ridge) and about 71N, 147W (continental shelf in southern Canada Basin). These samples were collected from hydrographic casts extending down to 1600m taken when the submarine was at the surface. The southernmost third of this section is incomplete because the surface stations in this region were aborted due to unstable ice conditions. The POGY samples were shipped to L-DEO in November 1996. Since then, all CFC, tritium/He-3, and O-18 samples from the POGY cruise have been analyzed.

To complete our tracer sampling plan originally planned for the 1996 POGY cruise, we collected 291 O-18, 167 CFC, and 111 tritium/He-3 samples during the 1997 ARCHERFISH cruise. Most of these samples were collected at 22 so-called spiral stations which provided us with up to eight depth levels per station. The SCICEX 97 samples were collected exclusively from the upper water column (operational depth of ARCHERFISH) providing us with samples that mainly cover the surface and halocline waters, as well as the transition zone into the Atlantic Water. Analysis of these samples is presently underway.

RESULTS: The results from this cruise will soon be posted on our WWW site:

Title: Viral Diversity and Mortality of phyto- and bacterioplankton in the Arctic Ocean
PI(s): Faroq Azam, Scripps Institution of Oceanography
Point of Contact: Faroq Azam,
SCICEX Cruise: 1996, 1997
Abstract: This project is an investigation of viral diversity and distribution, and the contribution of viruses to bacterial mortality in the Arctic Ocean basin. Seawater collection and fixation and the concentration of viruses from seawater samples were conducted during the SCICEX 96 and 97 cruises aboard U. S. Navy nuclear submarines. Total counts of viruses and bacteria have been determined for SCICEX 97 samples by epifluorescence microscopy. Preliminary analysis of these counts reveals elevated viral abundance in Pacific-derived waters entering the Arctic Ocean via the Chukchi Sea. Viral concentrates from both cruises are currently being analyzed by pulsed field gel electrophoresis (PFGE) to determine spatial and temporal variations in the viral community. Preliminary results indicate remarkable similarities in viral genome size distributions on a basin-wide spatial scale, with most genomes tending to cluster in three size domains around 35, 65 and 175 kb. More detailed analysis by probing and sequencing are planned to determine the degree of heterogeneity within these domains and their possible ecological significance. For samples taken on both cruises, viral mortality of bacteria is also being estimated by electron microscopic determination of the frequency of visibly-infected cells (FIC). Variations in viral abundance, community composition and infection frequency will be related to other hydrographic and biological variables evaluate those which may be important in regulating viral propagation.

Title: Submarine-based acoustic doppler current profiler (ADCP) measurements of the Arctic Ocean upper halocline
PI(s): Robin Muench, Earth and Space Research
Point of Contact: Robin Muench,
SCICEX Cruise: 1996, 1997, 1998
Abstract: This project acquires underway current profile data from the upper Arctic Ocean using an upward looking acoustic doppler current profiler (adcp) mounted atop a submarine. These data are used to document vertical shear and to characterize currents associated with mesoscale eddies and frontal structures. The shear data are being used in conjunction with concurrently obtained conductivity/temperature/depth (CTD) data and with data obtained from other platforms to assess vertical mixing and heat flux over a broad geographical area of the upper Arctic Ocean. The information on eddies and fronts is being used, in conjunction with CTD data and with data from other platforms, to compile a mesoscale climatology of the Arctic Ocean and to assess the importance of mesoscale features in lateral property transport. Results of this work are anticipated to increase our understanding of internal Arctic Ocean mixing processes and, concurrently, our grasp of ocean-ice interactions and of shelf-basin property exchanges.

Title: Ice thickness distribution test
PI(s): Drew Rothrock, Gary Maykut, University of Washington and Alan Thorndike, University of Puget Sound
Point of Contact: Drew Rothrock,
SCICEX Cruise: 1996, 1997, 1998
Abstract: The arctic ice pack is composed of many different thicknesses of ice, each having different physical properties and each interacting differently with the atmosphere and ocean. Information on the ice thickness distribution is critical for calculating ice properties such as surface temperature, albedo, strength and deformation, as well as for estimating regional fluxes of mass, heat and salt. A theory has been formulated (Thorndike et. al., 1975) to predict temporal changes in the distribution g of ice thickness h. This theory has become an integral part of many sea ice models, yet it involves assumptions about such physical processes as the formation of leads and ridges that are little more than guesses, and it ignores other important processes such as the effects of variable snow thickness, melting at floe edges and melt ponds. Since its initial development twenty years ago, the theory has not been directly tested, primarily because of a lack of suitable data. The convergence of SCICEX cruises with the Surface Heat Balance of the Arctic (SHEBA) field experiment in the Beaufort Sea offers a unique opportunity to obtain the needed data. As a precursor, during SCICEX ‘96 very dense ice draft measurements were collected within an area 200 km across. Important issues to be examined with these data involve the size of the area that needs to be measured, the "completeness" with which it must be measured, the size of the error bars involved and the behavior of the model over intervals as short as 4 weeks. The results will enable us to put error bars on observations of ice thickness distribution and to recommend efficient sampling and analysis strategies. With the submarine’s upward-looking sonar, we are surveying a Lagrangian area of sea ice including the SHEBA ship in 1997, and 1998 and the vacated SHEBA site in1999. By comparing the ice thickness observations at the two different times we will test time-dependent predictions of the thickness distribution theory. During the period spanning SCICEX ‘97 and ‘98 ice growth and heat fluxes will be available from SHEBA observations, and ice deformation will be obtained from the RADARSAT Geophysical Processor System. These thermodynamic and kinematic forcing data will allow us to calculate the time history of ice thickness distribution, which will be initialized with thickness distributions from one submarine survey and tested with those from a later survey. Throughout the entire SHEBA experiment, we plan to estimate ice thickness distributions continuously, providing information crucial to the larger-scale objectives of SHEBA.

Title: What Are the Sources and Significance of Dissolved Organic Carbon and Nutrient Signals Within the Arctic Basin?
PI(s): Terry Whitledge and R. Benner, Univ. Texas
Point of Contact: Terry E Whitledge
SCICEX Cruise: 1997, 1998
Abstract: The proposed studies would investigate various aspects of the sources, transformations, and fates of dissolved nutrients and organic matter in the Arctic Ocean. Seawater samples (~1,200 total) would be collected during U.S. Navy submarine cruises in the Arctic Ocean during 1997-1999 for the analysis of nutrients (NH4, NO3, NO2. PO4, SiO4) and total organic carbon (TOC), nitrogen (TON) and phosphorous (TOP). The concentrations of lignin-derived phenols dissolved in seawater would also be measured to provide an estimate of the contribution of terrestrially-derived organic carbon to TOC in Arctic Basins. The concentrations and distributions of nutrients and organic matter will be evaluated to determine: 1) if the Bering Strait/Chukchi Sea is a significant source of carbon and nutrients to the Arctic basins, 2) whether Arctic rivers are significant sources of organic matter to basin carbon budgets, 3) if organic matter in the Arctic is a sink for atmospheric carbon dioxide, 4) if biological processes within the Arctic Ocean are responsible for elevated concentrations of TOC.

Title: Collaborative research: Integrated geophysical study of the Arctic Mid-ocean Ridge and Alpha Ridge from a nuclear submarine
PI(s): Bernie Coakley, James Cochran, LDEO and Margo Edwards, University of Hawaii
Point of Contact: Margo Edwards,
SCICEX Cruise: 1998, 1999
Abstract: We propose to conduct a sidescan, swath bathymetry and gravity survey of the 1500 km length of the AMOR. This data will permit us to characterize the neovolcanic zone, the faults which form the axial valley, and ridge axis offsets to determine how ridge axis tectonics, morphology and segmentation change at extremely slow spreading rates. The gravity data will also allow us to investigate variations in crustal thickness on both a local and regional scale. Extending the survey onto the ridge flanks in this area will allow us to study the abyssal hills to determine differences in near-axial tectonics and the balance between volcanic and tectonic activity associated with different modes of crustal generation.

Title: Quantitative variability in acoustic backscatter due to zooplankton and concurrent hydrography in the Arctic Ocean
PI(s): Gwyn Griffith and Howard Roe, University of Southampton
Point of Contact: Gwyn Griffith
SCICEX Cruise: 1997, 1998
Abstract: Our project uses raw data that has been gathered by other SCICEX Pis for their purposes, essentially, the ADCP data set (Muench), SSXCTD & Icecat underway CTD. As such we assume that the primary data users will archive the raw data at the US National Snow and Ice Data Center. We 'add value' to the ADCP backscatter data by careful calibration, merging with other data and interpretation. We can make this processed data available to the Data Center in due course; our target is to have a processed data set completed for SCICEX '97 by the end of 1998.

Title: Upper Arctic Ocean variability
PI(s): Tim Boyd, Oregon State University
Point of Contact: Tim Boyd
SCICEX Cruise: 1998
Abstract: The location and structure of upper ocean water masses in the region of the Atlantic/Pacific front will be mapped underway using an upward-looking 150 kHz ADCP, sail-mounted CTD and submarine-launched expendable CTDs (XCTDs). Calibration of XCTDs as well as additional velocity and hydrographic observations will be made at intermittent surface stations using a wire-lowered CTD and ADCP.

Title: Heat content of summer mixed layer and its impact on the surface heat balance in the arctic
PI(s): Gary Maykut, University of Washington and Miles McPhee, McPhee Research
Point of Contact: M. McPhee,
SCICEX Cruise: 1998
Abstract: The growth and overall thickness of sea ice is sensitive to the flux of sensible heat (Fw) released from the ocean at the underside of the ice. In the Arctic, the primary source of energy for Fw is shortwave radiation that enters the upper ocean through leads, thin ice and melt ponds during the late spring and summer. Little is known, however, about the spatial variability of Fw, about the effects of advection on measured values of Fw or about the exact relationship between ocean heat content, summer ice concentration and mass changes in the ice cover. This project will address these problems using submarine temperature, salinity and ice thickness data obtained from horizontal transects through the mixed layer in the vicinity of the SHEBA ice station in the Beaufort Sea. The overall objective is to develop a simplified treatment of shortwave interactions in the upper ocean that can be incorporated into large-scale models for the prediction of spatial and temporal variations in Fw and its effect on the heat and mass balance of the ice cover. Specific goals are: (1) to determine the degree to which Fw measurements at a single site (e.g., an ice camp or buoy) represent average values within a larger region such as a GCM grid cell, and (2) to test our ability to estimate solar heat input to the mixed layer on a regional scale. By combining the submarine observations with routine data on incoming shortwave radiation, ice thickness, ice growth, ice velocity and upper ocean structure taken as part of the SHEBA Program, it should then be possible to obtain a more quantitative understanding of how shortwave radiation affects the seasonal evolution of the mixed layer and its interaction with the ice pack.

Title: SCICEX 98 and 99: tracer studies of the large scale circulation of the upper and intermediate waters in the Canadian Basin'
PI(s): Peter Schlosser and Bill Smethie, LDEO
Point of Contact: P. M. Schlosser,
SCICEX Cruise: 1998
Abstract: We plan to continue our tracer survey (tritium/He-3, CFCs, oxygen isotopes) of the Canadian Basin of the Arctic Ocean in the framework of the planned submarine cruises (SCICEX) in 1998 and 1999. Our previous tracer work using submarines as platforms were successful in (1) demonstrating the feasibility of such work from submarines (PARGO for tritium/He-3 and O-18, and POGY for CFCs), and (2) in revealing important new information on the circulation patterns and spreading times of surface and especially intermediate waters in the Canadian Basin. To complete the first large-scale tracer survey of the upper 1600 meters in the Canadian Basin we propose to collect, measure, and interpret about 500 tritium/He-3, 800 O-18, and 500 CFC (CFC-11, CFC-12, and CFC-113) samples in the framework of the planned 1998 and 1999 SCICEX expeditions. The measurements will be used, together with hydrographic and previously obtained tracer data (e.g., PARGO, POGY cruises, AOS 94), to (1) study the transport of shelf waters into the Arctic halocline, (2) derive evolution, circulation patterns, and mean residence times of the upper waters in the Canadian Basin, (3) delineate pathways and storage times of river runoff and sea-ice meltwater in the upper layers of the Canadian Basin, (4) to test hypotheses about the spreading patterns and rates of intermediate waters from their source in the Eurasian Basin throughout the Canadian Basin, and (5) to calibrate Arctic Ocean circulation models.

Data compiled and formatted by Randy Jacobson, Office of Naval Research, February, 1998.