SIDEBAR 2-11 Managing Ice Cores at the National Ice Core Laboratory

The National Ice Core Laboratory (NICL), at the Denver Federal Center in Lakewood, Colorado, manages ice cores collected and used primarily by NSF- and USGS-funded researchers, and other government personnel. A web-based catalog (www.nicl.usgs.gov) enables potential users to determine current holdings. Through an outreach program, NICL introduces people of all ages to ice-core science.

With holdings of 15,700 meters (51,509 feet) of ice core (see photograph in sidebar) at -36° Celsius, NICL is currently at 90 percent capacity. Implementation of a staged plan for a new, mobile racking system will increase available space from 10 to 48 percent, thus deferring space problems for several years.

NICL has operated under an inter-agency agreement between the USGS and NSF since opening in 1993. The annual budget ($477,000 in 2000) is shared equally between these partners. USGS has responsibility for facility operations, while NSF provides oversight that includes periodic performance reviews. Science management (including decision making on sample allocation and accession and deaccession protocols) is coordinated by the University of New Hampshire under a competitive contract. The director of scientific management bases his or her guidance on advice from an Ice Core Working Group (ICWG). The ICWG is a group of 11 experts from universities and the USGS who actively work on ice cores and/or use data derived from ice cores.

Accession and deaccession protocols are promulgated by NSF using a subgroup of the ICWG as an advisory committee. This removes NICL from potential conflicts of interest on such matters. To be accepted by NICL, ice cores must arrive with site information and logging information for each meter section of core. This information should be in digital form. For smaller-diameter (4-inch) cores of opportunity, a removal date must be established upon accession. Because of the necessary high levels of coordination for deep drilling projects in Greenland and Antarctica, NICL has advance notice of incoming large-diameter (5.2-inch) cores and can plan accordingly. Currently approximately 1,000 meters per year (3,281 feet per year) of new core are collected in a typical drilling season. This plan may include deaccession of older core, a process overseen by the ICWG. Criteria for deaccession, each assessed on a scale of 1 to 5 by scientists, are age, continuity, volume, robust dating, published information, number of requests, core quality, duplication, drilling method, specific utility, uniqueness, and site accessibility. Deaccessioned ice offers a testing ground for new analytical methodologies such as extraction of CO2 from air bubbles (Sidebar 1-7). Deaccesioned cores are advertised through e-mail and print to a broad cross-section of the scientific community. In June 2001 approximately 1,588 meters (5,210 feet) of core were on the deaccession list, and another 477 meters (1,565 feet) were shipped to scientists and school outreach programs in the preceding year. Ice is not discarded until NICL needs the storage space, and only then after many others have passed on the opportunity to take the ice themselves.

Committee Conclusions of Best Practices: (1) web-based catalogue of metadata; (2) inter-agency and federal/university support; (3) community-based, science- and user-oversight committee; (4) well-documented and well-advertised deaccession protocols that result in little wasted core; (5) adequate fiscal support (as of 2001).

The committee visited NICL in June, 2001.

Inside the National Ice Core Laboratory. The ice core storage room is maintained at a temperature of –33°F (–36°C). About three-quarters of the NICL collection is in 1-meter (3.3-foot) tubes, the other quarter is in 1.5-meter (5-foot) tubes. Each tube contains part of a single core. SOURCE: Geoffrey Hargreaves, NICL.



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