HR: 0800h
AN: OS41A-0477    [Abstracts]
TI: A Multi-Tracer Analysis for the Study of the Movement and Mixing of Fresh Waters in a Shallow Arctic Estuarine System
AU: * Alkire, M B
EM: malkire@fit.edu
AF: Florida Institute of Technology, 150 West University Boulevard, Melbourne, FL 32901 United States
AU: Trefry, J H
EM: jtrefry@fit.edu
AF: Florida Institute of Technology, 150 West University Boulevard, Melbourne, FL 32901 United States
AU: Rember, R D
EM: rrember@iarc.uaf.edu
AF: IARC - Frontier, University of Alaska, Fairbanks, 930 Koyukuk Drive, Fairbanks, AK 99775 United States
AU: Savoie, M
EM: msavoie@kinneticlabs.com
AF: Kinnetic Laboratories, Inc., 403 West 8th Avenue, Anchorage, AK 99501 United States
AU: Trocine, R P
EM: rtrocine@fit.edu
AF: Florida Institute of Technology, 150 West University Boulevard, Melbourne, FL 32901 United States
AU: Woodall, D W
EM: dwoodall@fit.edu
AF: Florida Institute of Technology, 150 West University Boulevard, Melbourne, FL 32901 United States
AB: Water samples were collected through 2-m thick ice in the shallow waters of the coastal Beaufort Sea during the spring maximum flow of the Kuparuk and Sagavanirktok rivers, Alaska, in late May to early June 2004. Sampling was carried out over an area of about 800 km$^2$ at water depths of 0.5, 1.0, 1.5, 2.5, 4, 6, 7, and 10 meters below the ice layer, depending on the total depth of the water column. Continuous profiles of temperature and salinity (CTD) and current measurements at key depths were obtained. Water from the two rivers and from sea ice has geochemical characteristics that are different from ambient seawater as well as from each other. Concentrations of conservative tracers, such as salinity, temperature and oxygen isotopes, as well as semi-conservative tracers, such as barium and dissolved silica are used to distinguish and measure seaward mixing of various source waters. For example, concentrations of dissolved silica in the Kuparuk River (13\pm1$\mu$M), the Sagavanirktok River (24\pm5$\mu$M) and sea ice (1.0\pm0.5$\mu$M) provide distinct signatures relative to the deeper Polar Mixed Layer (PML) with silica levels of 7.6\pm0.8$\mu$M. Similar trends are demonstrated with the other tracers. Mixing was traced horizontally (x, y) and vertically (z) throughout the sampling area, and temporally (t) at selected sites. A 1-2 m thick lens of predominately fresh water could be traced 10-12 km offshore. Combined use of the various tracers shows dissipation of geochemically different freshwater signals into the ambient PML of the Beaufort Sea during the spring floods.
DE: 4808 Chemical tracers
DE: 4207 Arctic and Antarctic oceanography
DE: 4283 Water masses
DE: 4568 Turbulence, diffusion, and mixing processes
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting