Accomplishments of the First U.S.-Russia cruise in the East-Siberian Sea onboard
the Hydrographic Vessel IVAN KIREEV

(10-23 September 2003)
See also: Research Highlight: The East Siberian Sea is a Natural Laboratory for Studying Climate Change

(by Igor Semiletov, Chief Scientist)

Justification

Scientific justification:

Any attempt to understand the effects of the Arctic Ocean on global change, or the effects of global change on the Arctic Ocean, requires a thorough understanding of coastal processes. The major transport of fresh water and dissolved and solid materials into the Arctic Ocean is determined by riverine discharges from Eurasia and North America and by coastal erosion (Codispoti et al., 1990; Grebmeir and Whitledge,1996; Boucsein et al., 2000; Semiletov et al., 2000). Therefore, coastal processes provide the critical link between land and ocean processes in the Arctic.

Beneath the Arctic Ocean lies the broadest continental shelf area in the World Ocean. The continental shelves occupy about 36% of the Arctic's oceanic area (MacDonald and Thomas, 1991). The widest and shallowest continental shelf in the Arctic Ocean lies beneath the East-Siberian Sea (ESS). A transect of the ESS corresponds to a number of geographically critical contrasts in the arctic system. This area remains largely unexplored and understudied and provides an excellent natural laboratory for improving understanding of the interactions across the atmosphere-land-ocean system and the impacts of those interactions on freshwater dynamics and biogeochemistry.

One of the key questions of biogeochemistry is how the flux of carbon and nutrients will be altered by long-range and interannual variability in the arctic atmosphere-land-shelf system. In order to address this question, we are investigating present conditions and the processes that govern near-shore fluxes and movement and interactions of materials in the East Siberian Arctic, using a combination of historical data and field studies combined with modern techniques

Logistic justification:

In May 2003, we received permission through Pacific Oceanological Institute (POI) (date of notification: May 15, 2003; issued by Russian Ministry of Industry, Science and Technology: order 71) for a joint Russia-U.S. cruise in the ESS. The two week cruise set sail from Tiksi in the summer of 2003. The National Science Foundation (NSF) provided funds for U.S. participation in the ESS cruise through an NSF- Office of Polar Programs (OPP) project, which was submitted by Igor Semiletov and Gunter Weller (OPP-0342837). This project connnected well with the NSF CHAMP project (OPP-0230455). Basic support for the cruise was provided by Academician Sergienko, President of the Far Eastern Branch of the Russian Academy of Sciences (FEBRAS). Partial support came from initiative projects of the Russian Foundation for Basic Research and the Siberian Branch of the Russian Academy of Sciences (SBRAS). The International Arctic Research Center (IARC) of the University of Alaska Fairbanks (UAF) contributed equipment and travel support for Alexander Makshtas. The Arctic and Antarctic Research Institute (AARI) contributed travel expenses for the AARI group.

Logistical support in Tiksi, and throughout the cruise, was provided by Dmitry Mel'nichenko, Tiksi Hydrobase, Hydrography Venture, and the Ministry of Transport, Russian Federation. Charter of the hydrographic vessel Ivan Kireev was arranged through a Cooperative Agreement between POI FEBRAS and Tiksi Hydrobase. Assistance from the VECO/NSF contractor was also very helpful.

Fig. 1 The scientific party in the First Russian-U.S. cruise in the East Siberian Sea.

This is the first real U.S.-Russian cooperative venture in this region and we have reason to believe that our Russian counterparts from the POI (coordinated by Igor Semiletov and Oleg Dudarev) and the AARI ( coordinated by Alexander Makshtas ) desire genuine cooperation in the future. The approval was the first positive response of the Russian Ministry of Science and Technology (which includes six Federal bodies including the General Staff/Ministry of Defense) to our Russian Far Eastern partner (POI), who has applied each year for a joint cruise in the Laptev/ESS. NSF and FEBRAS viewed this cruise as a test cruise to demonstrate to both sides how a future partnership could be developed. Note that this cruise demonstrates the first cooperative research between POI and AARI in the Arctic Ocean. It was supported personally by academician Valentin Sergienko and Dr. Alexander Danilov, Deputy Director, AARI.

Accomplishments and Expected Results

Surprise permission for a joint Russia-U.S. cruise to the ESS, in the summer of 2003, allowed five U.S. researchers from the UAF International Arctic Research Center and the University of South Carolina (USC) to cooperate with a Russian scientific team of thirteen scientists. The combined team conducted research to elucidate the fate of terrestrial eroded carbon and riverine waters from East-Siberian watersheds to the ESS shelf seas. Using modern instruments, the research crew sampled water, particulate matter, and sediments along three transects - across the Dmitry Laptev and Sannikov Straits, in the west and the Long Strait in the east. In total, samples were harvested at 44 oceanographic stations across the Straits and nearshore zone (Fig.2). A set of hydrochemical measurements were conducted immediately after sampling (pH, dissolved oxygen, dissolved methane), or directly in situ (PAR, Colloidal Dissolved Organic Material [CDOM], turbidity). Additional measurements (nutrients, Dissolved Organic Carbon [DOC], O¹⁸, C¹³, N¹⁵, biomarkers, chemical composition) in water and sediment will be done after the cruise, using facilities at UAF and FEBRAS. The SBRAS group was responsible for the sediment coring; their samples will be analyzed later using SBRAS and USC facilities. Hopefully, the Acoustic Doppler Current Profiler (ADCP) data obtained and corrected by USC will be available soon for the cruise participants. Also, continuous measurements of air CO₂ and pCO₂ and temperature/salinity along the ship's track were taken for the first time in the Siberian arctic seas.

Fig.2.   The study area with position of oceanographic stations and continuous measurement of air CO₂, pCO₂ , temperature, salinity along the ship's track (September 10-23, 2003).

Our transect of the ESS provides new measurements across the widest, shallowest, and least explored area in the World Ocean. This area represents a "boundary zone" between local shelf waters and Pacific derived waters (Fig.3).

Fig.3. The transect along the East-Siberian Sea coast performed in September-2003 onboard Ivan Kireev (Semiletov and the Scientific cruise party, unpublished)

New CTD and biogeochemical data will contribute significantly towards understanding how the hydrological and hydrochemical parameters respond to short-term changes in atmospheric conditions. These data will help to elucidate connections between atmospheric forcing, river discharge, and oceanological processes over the arctic Eurasian shelf, with a special eye towards the westward penetration of the Pacific-derived waters. New data will also help to construct a believable present-day regional summertime CO₂ budget, which is essential for reliable prediction of changes in atmospheric CO₂ in connection with sea ice, atmosphere, and water circulation changes. Other expected results are listed below:

1. New CTD and biogeochemical data will contribute significantly towards understanding how hydrological and hydrochemical parameters respond to short-term changes in atmospheric condition, revealing connections between atmospheric forcing, river discharge and oceanological processes over the continental shelves.
2. Detailed nutrient data will allow us to examine well-known indicators of hydrochemical processes (such as N* and NO/PO) that can be used jointly with other reliable data (such as data collected during the KOLOMEYTSEV-2000 and NORTH WIND-1963 cruises).
3. New data collected from sediments (C¹³, N¹⁵, OC/ON) will be used to identify a "mean boundary" of westward penetration of Pacific derived waters into the ESS.
4. Measurements of CDOM will be used to trace DOC concentrations in the arctic regions through the relationship between CDOM and DOC concentration. The interactions of Siberian river waters with arctic shelf waters will be examined using both Dissolved Organic Material (DOM) and POM data.
5. CDOM and DOC data, together with oxygen stable isotopic composition, will allow us to use CDOM as a tracer, especially in the nearshore zone, to examine the influence of freshwater and melt water mixing in the eastern Siberian shelf. In addition, the dynamic cycling of organic carbon will be further revealed by the stable isotopic composition and the chemical composition of DOM (such as carbohydrate species) and CDOM (optical properties, etc.).
6. Optical data will be joined with biogeochemical data to elucidate how water transparency is related to biogeochemical factors.
7. Meteorological data and synoptic analysis will allow us to investigate how air mass transport effects the air CO₂ distribution and related CO₂ fluxes between the atmosphere and the sea.
8. Continuous measurement of pCO₂ temperature and salinity along the ship's track from the 4m horizon, in conjunction with the CTD data, will be used to identify the frontal zones.
9. In situ turbidity data will be calibrated by the filtering technique and used to build a reliable picture of the particulate matter distribution in the near-shore zone.
10. Dissolved methane distribution will help to evaluate the methane exchange between air and water, and, also, between water and bottom sediments.

Broader Impacts and Intellectual Merit

The work accomplished thus far has promoted teaching and training through support for graduate students (two from the U.S., and two from Russia). The project will provide a web site accessible to the public and especially intended for undergraduate students, after the data analyses are complete. This project will enhance collaboration by providing an opportunity for U.S. based workers to collaborate on a common project in the Asian Arctic on Pan-Arctic land-shelf and shelf-basin interactions. This is the first real international cooperative venture in this region between the U.S. (UAF and USC), Russia (FEBRAS, AARI, and SBRAS), and Japan (IARC, JAMSTEC).

Experience working in the Russian Economic Enterprise Zone (EEZ) (including logistics and custom issues) will help when planning future U.S. studies in this area. This project is a good start towards the goal of establishing a long-term mutual cooperation in the Pacific sector of the Arctic Ocean (mostly Russian EEZ) between the U.S., FEBRAS, and AARI.