Kadko Metadata ---TITLE: 226Ra and 228Ra SBI Phase I ---AUTHOR: David Kadko -Complete mailing address, telephone/facsimile Nos., web pages and E-mail address of PI Dr. David Kadko University of Miami RSMAS/MAC 4600 Rickenbacker Causeway Miami, FL 33149 tel; 305 421 4721 fax 305 421 4689 dkadko@rsmas.miami.edu ---FUNDING SOURCE AND GRANT NUMBER: National Science Foundation Office of Polar Programs OPP -9815132 ---DATA SET OVERVIEW: -Introduction or abstract The main goal of the (SBI) program is to understand the physical and biological processes within the shelf/slope of the Chukchi and Beaufort Seas that influence the structure and functioning of the Arctic Ocean. This program focuses on understanding exchange and interaction between Arctic shelves and the basin. To this end, our PHASE I program explored the use of an isotopic tracer technique to investigate the rate of exchange between the Arctic shelves and the Arctic Ocean interior. The technique utilizes the measurement of the water column ratio of the naturally occurring radium isotopes 228Ra/226Ra. Because 228Ra (T1/2= 5.77y) is derived through input from shelf sediments, it is an unambiguous marker of water that has been in contact with shelves. Its relative distribution in shelf and basin water is therefore very valuable in assessing the degree of shelf- basin interaction. -Time period covered by the data June 1998 - October 1998; August 2000 -Physical location of the measurement or platform (latitude/longitude/elevation) Chukchi and Beaufort Seas in the Western Arctic Ocean -Data source, if applicable (e.g. for operational data include agency) NA -Any World Wide Web address references (i.e. additional documentation such as Project WWW site) NA ---INSTRUMENT DESCRIPTION: NA ---DATA COLLECTION and PROCESSING: Radium isotopes were extracted upon manganese - coated acrylic fibers through which seawater, sampled from niskin bottles, or pumped from the seasurface, flowed. It has been shown that these fibers adsorb radium isotopes efficiently and without fractionation (Moore et al., 1995). In the process, approximately 60-200 L of seawater were slowly drained through a plastic tube filled with the Mn-fiber. The fibers were subsequently sealed in petrie dishes where, on land, the 228Ra/226Ra activity ratio was determined by measuring the activity of the radium daughters by gamma ray spectrometry (e.g. Michel et al., 1981). The counting system is calibrated with known radioactive sources in a geometry that matches that of the fiber samples. Our laboratory utilizes two low background, high efficiency germanium detectors. ---DATA FORMAT: -Data file structure, format and file naming conventions (column delimited ASCII) -List of parameters with units, sampling intervals, frequency, range Data are given in units of dpm/100L (disintegrations per minute per 100 liters of seawater). -Data version number and date Final. March 29, 2005 ---DATA REMARKS: NONE ---REFERENCES: Michel J., Moore W.S. and King P.T. (1981) -Ray spectrometry for determination of radium-228 and radium-226 in natural waters. Anal.chem. 53,1885-1889. Moore W.S., R.M. Key and J.L. Sarmiento (1985) Techniques for precise mapping of 226Ra and 228Ra in the ocean. Journ. Geophy. Res., 90, 6983-6994.