Influences on Mercury Bioaccumulation Factors for the Savannah River (open access)

Influences on Mercury Bioaccumulation Factors for the Savannah River

Mercury TMDLs (Total Maximum Daily Loads) are a regulatory instrument designed to reduce the amount of mercury entering a water body and ultimately to control the bioaccumulation of mercury in fish. TMDLs are based on a BAF (bioaccumulation factor), which is the ratio of methyl mercury in fish to dissolved methyl mercury in water. Analysis of fish tissue and aqueous methyl mercury samples collected at a number of locations and over several seasons in a 118 km reach of the Savannah River demonstrated that species specific BAFs varied by factors of three to eight. Factors contributing to BAF variability were location, habitat and season related differences in fish muscle tissue mercury levels and seasonal differences in dissolved methyl mercury levels. Overall (all locations, habitats, and seasons) average BAFs were 3.7 x 106 for largemouth bass, 1.4 x 106 for sunfishes, and 2.5 x 106 for white catfish. Inaccurate and imprecise BAFs can result in unnecessary economic impact or insufficient protection of human health. Determination of representative and precise BAFs for mercury in fish from large rivers necessitates collecting large and approximately equal numbers of fish and aqueous methyl mercury samples over a seasonal cycle from the entire area and all …
Date: May 6, 2003
Creator: Paller, M.H.
Object Type: Article
System: The UNT Digital Library
Bench-scale testing of the multi-gravity separator in combination with microcel. Fourth quarterly report, July 1, 1993--September 30, 1993 (open access)

Bench-scale testing of the multi-gravity separator in combination with microcel. Fourth quarterly report, July 1, 1993--September 30, 1993

Work this quarter included equipment installation, shakedown testing, and the beginning of the detailed testing program. With the exception of ongoing Task 4: Sample Characterization, Tasks 1 through 8 are now complete. Task 10: Detailed Testing and Task 12: Sample Analysis began this quarter and will consume all available time during the 5th quarter. Installation and testing of the process equipment, mechanical systems, as well as the electrical systems were completed. The shakedown process uncovered several necessary modifications to the circuit which were subsequently completed. Most of the changes concerned piping and valving modifications which allowed for better material flow and sampling. The circuit was operated with coal to determine the time for each unit to reach steady state. The primary objective of the proposed work is to design, install, and operate an advanced fine coal processing circuit combining the Microcel{trademark} and Multi-Gravity-Separator (MGS) technologies. Both of these processes have specific advantages as stand-alone units. For example, the Microcel column effectively removes ash-bearing mineral matter, while the MGS efficiently removes coal-pyrite composites.
Date: December 6, 1993
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Managing Aging Effects on Dry Cask Storage Systems for Extended Long-Term Storage and Transportation of Used Fuel - Rev. 0 (open access)

Managing Aging Effects on Dry Cask Storage Systems for Extended Long-Term Storage and Transportation of Used Fuel - Rev. 0

The cancellation of the Yucca Mountain repository program in the United States raises the prospect of extended long-term storage (i.e., >120 years) and deferred transportation of used fuel at operating and decommissioned nuclear power plant sites. Under U.S. federal regulations contained in Title 10 of the Code of Federal Regulations (CFR) 72.42, the initial license term for an Independent Spent Fuel Storage Installation (ISFSI) must not exceed 40 years from the date of issuance. Licenses may be renewed by the U.S. Nuclear Regulatory Commission (NRC) at the expiration of the license term upon application by the licensee for a period not to exceed 40 years. Application for ISFSI license renewals must include the following: (1) Time-limited aging analyses (TLAAs) that demonstrate that structures, systems, and components (SSCs) important to safety will continue to perform their intended function for the requested period of extended operation; and (2) a description of the aging management program (AMP) for management of issues associated with aging that could adversely affect SSCs important to safety. In addition, the application must also include design bases information as documented in the most recent updated final safety analysis report as required by 10 CFR 72.70. Information contained in previous …
Date: July 6, 2012
Creator: Chopra, O. K.; Diercks, D.; Fabian, R.; Ma, D.; Shah, V.; Tam, S. W. et al.
Object Type: Report
System: The UNT Digital Library
ESG-CET Final Progress Title (open access)

ESG-CET Final Progress Title

Drawing to a close after five years of funding from DOE's ASCR and BER program offices, the SciDAC-2 project called the Earth System Grid (ESG) Center for Enabling Technologies has successfully established a new capability for serving data from distributed centers. The system enables users to access, analyze, and visualize data using a globally federated collection of networks, computers and software. The ESG software - now known as the Earth System Grid Federation (ESGF) - has attracted a broad developer base and has been widely adopted so that it is now being utilized in serving the most comprehensive multi-model climate data sets in the world. The system is used to support international climate model intercomparison activities as well as high profile U.S. DOE, NOAA, NASA, and NSF projects. It currently provides more than 25,000 users access to more than half a petabyte of climate data (from models and from observations) and has enabled over a 1,000 scientific publications.
Date: October 6, 2011
Creator: Middleton, Don
Object Type: Report
System: The UNT Digital Library
Hanford Site Transuranic (TRU) Waste Certification Plan (open access)

Hanford Site Transuranic (TRU) Waste Certification Plan

As a generator of transuranic (TRU) and TRU mixed waste destined for disposal at the Waste Isolation Pilot Plant (WIPP), the Hanford Site must ensure that its TRU waste meets the requirements of US. Department of Energy (DOE) 0 435.1, ''Radioactive Waste Management,'' and the Contact-Handled (CH) Transuranic Waste Acceptance Criteria for the Waste Isolation Pilot Plant (WIPP-WAC). WIPP-WAC requirements are derived from the WIPP Technical Safety Requirements, WIPP Safety Analysis Report, TRUPACT-II SARP, WIPP Land Withdrawal Act, WIPP Hazardous Waste Facility Permit, and Title 40 Code of Federal Regulations (CFR) 191/194 Compliance Certification Decision. The WIPP-WAC establishes the specific physical, chemical, radiological, and packaging criteria for acceptance of defense TRU waste shipments at WIPP. The WPP-WAC also requires that participating DOE TRU waste generator/treatment/storage sites produce site-specific documents, including a certification plan, that describe their program for managing TRU waste and TRU waste shipments before transferring waste to WIPP. Waste characterization activities provide much of the data upon which certification decisions are based. Waste characterization requirements for TRU waste and TRU mixed waste that contains constituents regulated under the Resource Conservation and Recovery Act (RCRA) are established in the WIPP Hazardous Waste Facility Permit Waste Analysis Plan (WAP). The …
Date: December 6, 2000
Creator: GREAGER, T.M.
Object Type: Report
System: The UNT Digital Library
Comparison of emerging diagnostic tools for large commercial HVAC systems (open access)

Comparison of emerging diagnostic tools for large commercial HVAC systems

Diagnostic software tools for large commercial buildings are being developed to help detect and diagnose energy and other performance problems with building operations. These software applications utilize energy management control system (EMCS) trend log data. Due to the recent development of diagnostic tools, there has been little detailed comparison among the tools and a limited awareness of tool capabilities by potential users. Today, these diagnostic tools focus mainly on air handlers, but the opportunity exists for broadening the scope of the tools to include all major parts of heating, cooling, and ventilation systems in more detail. This paper compares several tools in the following areas: (1) Scope, intent, and background; (2) Data acquisition, pre-processing, and management; (3) Problems detected; (4) Raw data visualization; (5) Manual and automated diagnostic methods and (6) Level of automation. This comparison is intended to provide practitioners and researchers with a picture of the current state of diagnostic tools. There is tremendous potential for these tools to help improve commercial building energy and non-energy performance.
Date: April 6, 2001
Creator: Friedman, Hannah & Piette, Mary Ann
Object Type: Article
System: The UNT Digital Library
Events of importance for week ending May 4, 1949 (open access)

Events of importance for week ending May 4, 1949

This report details events of importance reported by the Hanford Operations Office for the week ending May 4, 1949.
Date: May 6, 1949
Creator: Schlemmer, F. C.
Object Type: Report
System: The UNT Digital Library
Workshop on core and sample curation for the National Continental Scientific Drilling Program (open access)

Workshop on core and sample curation for the National Continental Scientific Drilling Program

The Workshop on Core and Sample Curation was held to discuss the best means of handling, distributing, and advertising samples and data collected during a Continental Scientific Drilling Program (CSDP) and to establish better communication between sample curators regarding common problems. It was geneerally agreed that CSDP samples should be handled, on a regional basis, by existing data systems and sample repositories judged to have adequate staff and support. Repository design, sample handling procedures, and sample accounting systems were discussed. Across North America, support for curation of geological samples was varied, but it was strongest within states or regions with well-established energy and mineral industries. A well-supported repository pays for itself through the circulation and preservation of samples and stratigraphic information. A national CSDP must have a well-established curatorial policy and system of regional repositories to circulate information and samples throughout the scientific community. Well-curated samples and data are a national resource with considerable benefits for industry and academia. Attendees agreed to form a Society of Geoscience Curators to maintain communication between curators from private, government, and university repositories and core research laboratories.
Date: May 6, 1981
Creator: Goff, S. & Heiken, G. (eds.)
Object Type: Article
System: The UNT Digital Library
Workshop Report on Atomic Bomb Dosimetry--Residual Radiation Exposure: Recent Research and Suggestions for Future Studies (open access)

Workshop Report on Atomic Bomb Dosimetry--Residual Radiation Exposure: Recent Research and Suggestions for Future Studies

There is a need for accurate dosimetry for studies of health effects in the Japanese atomic bomb survivors because of the important role that these studies play in worldwide radiation protection standards. International experts have developed dosimetry systems, such as the Dosimetry System 2002 (DS02), which assess the initial radiation exposure to gamma rays and neutrons but only briefly consider the possibility of some minimal contribution to the total body dose by residual radiation exposure. In recognition of the need for an up-to-date review of the topic of residual radiation exposure in Hiroshima and Nagasaki, recently reported studies were reviewed at a technical session at the 57th Annual Meeting of the Health Physics Society in Sacramento, California, 22-26 July 2012. A one-day workshop was also held to provide time for detailed discussion of these newer studies and to evaluate their potential use in clarifying the residual radiation exposures to the atomic-bomb survivors at Hiroshima and Nagasaki. Suggestions for possible future studies are also included in this workshop report.
Date: June 6, 2013
Creator: unknown
Object Type: Report
System: The UNT Digital Library
IDENTIFICATION, PRODUCTION AND CHARACTERIZATION OF NOVEL LIGNASE PROTEINS FROM TERMITES FOR DEPOLYMERIZATION OF LIGNOCELLULOSE (open access)

IDENTIFICATION, PRODUCTION AND CHARACTERIZATION OF NOVEL LIGNASE PROTEINS FROM TERMITES FOR DEPOLYMERIZATION OF LIGNOCELLULOSE

Wood is a potential source for biofuels such as ethanol if it can be digested into sugars and fermented by yeast. Biomass derived from wood is a challenging substrate for ethanol production since it is made of lignin and cellulose which cannot be broken down easily into fermentable sugars. Some insects, and termites in particular, are specialized at using enzymes in their guts to digest wood into sugars. If termite gut enzymes could be made abundantly by a recombinant protein expression vector system, they could be applied to an industrial process to make biofuels from wood. In this study, a large cDNA library of relevant termite genes was made using termites fed a normal diet, or a diet with added lignin. A subtracted library yielded genes that were overexpressed in the presence of lignin. Termite gut enzyme genes were identified and cloned into recombinant insect viruses called baculoviruses. Using our PERLXpress system for protein expression, these termite gene recombinant baculoviruses were prepared and used to infect insect larvae, which then expressed abundant recombinant termite enzymes. Many of these expressed enzymes were prepared to very high purity, and the activities were studied in conjunction with collaborators at Purdue University. Recombinant termite …
Date: December 6, 2012
Creator: Slack, Jeffrey M.
Object Type: Report
System: The UNT Digital Library
Methanogenic Conversion of CO2 Into CH4 (open access)

Methanogenic Conversion of CO2 Into CH4

This SBIR project evaluated the potential to remediate geologic CO2 sequestration sites into useful methane gas fields by application of methanogenic bacteria. Such methanogens are present in a wide variety of natural environments, converting CO2 into CH4 under natural conditions. We conclude that the process is generally feasible to apply within many of the proposed CO2 storage reservoir settings. However, extensive further basic R&D still is needed to define the precise species, environments, nutrient growth accelerants, and economics of the methanogenic process. Consequently, the study team does not recommend Phase III commercial application of the technology at this early phase.
Date: May 6, 2012
Creator: Stevens, S.H., Ferry, J.G., Schoell, M.
Object Type: Report
System: The UNT Digital Library
Preparing for Terrorist Attacks that Use Next-Generation Pathogens (open access)

Preparing for Terrorist Attacks that Use Next-Generation Pathogens

None
Date: January 6, 2005
Creator: Fitch, J P
Object Type: Report
System: The UNT Digital Library
Final Report for ARM Project Measuring 4-D Water Vapor Fields with GPS (open access)

Final Report for ARM Project Measuring 4-D Water Vapor Fields with GPS

Water vapor is a primary element in the Earth’s climate system. Atmospheric water vapor is central to cloud processes, radiation transfer, and the hydrological cycle. Using funding from Department of Energy (DOE) grant DE-FG03-02ER63327, the University Corporation for Atmospheric Research (UCAR) developed new observational techniques to measure atmospheric water vapor and applied these techniques to measure four dimensional water vapor fields throughout the United States Southern Great Plains region. This report summarizes the development of a new observation from ground based Global Positioning System (GPS) stations called Slant Water Vapor (SW) and it’s utilization in retrieving four dimensional water vapor fields. The SW observation represents the integrated amount of water vapor between a GPS station and a transmitting satellite. SW observations provide improved temporal and spatial sampling of the atmosphere when compared to column-integrated quantities such as preciptitable water vapor (PW). Under funding from the DOE Atmospheric Radiation Measurement (ARM) program, GPS networks in the Southern Great Plains (SGP) region were deployed to retrieve SW to improve the characterization of water vapor throughout the region. These observations were used to estimate four dimensional water vapor fields using tomographic approaches and through assimilation into the MM5 numerical weather model.
Date: February 6, 2006
Creator: Braun, John
Object Type: Report
System: The UNT Digital Library
Rockwell International Hot Laboratory decontamination and dismantlement interim progress report 1987-1996 (open access)

Rockwell International Hot Laboratory decontamination and dismantlement interim progress report 1987-1996

OAK A271 Rockwell International Hot Laboratory decontamination and dismantlement interim progress report 1987-1996. The Rockwell International Hot Laboratory (RIHL) is one of a number of former nuclear facilities undergoing decontamination and decommissioning (D&D) at the Santa Susana Field Laboratory (SSFL). The RIHL facility is in the later stages of dismantlement, with the final objective of returning the site location to its original natural state. This report documents the decontamination and dismantlement activities performed at the facility over the time period 1988 through 1996. At this time, the support buildings, all equipment associated with the facility, and the entire above-ground structure of the primary facility building (Building 020) have been removed. The basement portion of this building and the outside yard areas (primarily asphalt and soil) are scheduled for D&D activities beginning in 1997.
Date: May 6, 1997
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Open Access Publishing in Particle Physics: A Brief Introduction for the Non-Expert (open access)

Open Access Publishing in Particle Physics: A Brief Introduction for the Non-Expert

Open Access to particle physics literature does not sound particularly new or exciting, since particle physicists have been reading preprints for decades, and arXiv.org for 15 years. However new movements in Europe are attempting to make the peer-reviewed literature of the field fully Open Access. This is not a new movement, nor is it restricted to this field. However, given the field's history of preprints and eprints, it is well suited to a change to a fully Open Access publishing model. Data shows that 90% of HEP published literature is freely available online, meaning that HEP libraries have little need for expensive journal subscriptions. As libraries begin to cancel journal subscriptions, the peer review process will lose its primary source of funding. Open Access publishing models can potentially address this issue. European physicists and funding agencies are proposing a consortium, SCOAP3, that might solve many of the objections to traditional Open Access publishing models in Particle Physics. These proposed changes should be viewed as a starting point for a serious look at the field's publication model, and are at least worthy of attention, if not adoption.
Date: June 6, 2007
Creator: Brooks, Travis C.
Object Type: Report
System: The UNT Digital Library
Instrumentation of LOTIS: Livermore Optical Transient Imaging System; a fully automated wide field of view telescope system searching for simultaneous optical counterparts of gamma ray bursts (open access)

Instrumentation of LOTIS: Livermore Optical Transient Imaging System; a fully automated wide field of view telescope system searching for simultaneous optical counterparts of gamma ray bursts

LOTIS is a rapidly slewing wide-field-of-view telescope which was designed and constructed to search for simultaneous gamma-ray burst (GRB) optical counterparts. This experiment requires a rapidly slewing ({lt} 10 sec), wide-field-of-view ({gt} 15{degrees}), automatic and dedicated telescope. LOTIS utilizes commercial tele-photo lenses and custom 2048 x 2048 CCD cameras to view a 17.6 x 17.6{degrees} field of view. It can point to any part of the sky within 5 sec and is fully automated. It is connected via Internet socket to the GRB coordinate distribution network which analyzes telemetry from the satellite and delivers GRB coordinate information in real-time. LOTIS started routine operation in Oct. 1996. In the idle time between GRB triggers, LOTIS systematically surveys the entire available sky every night for new optical transients. This paper will describe the system design and performance.
Date: March 6, 1998
Creator: Park, H. S.; Ables, E.; Barthelmy, S. D.; Bionta, R. M.; Ott, L. L.; Parker, E. L. et al.
Object Type: Article
System: The UNT Digital Library
Software Configuration Management Plan for the Sodium Removal System (open access)

Software Configuration Management Plan for the Sodium Removal System

This document establishers the Software Configuration Management Plan (SCMP) for the software associated with the control system of the Sodium Removal System (SRS) located in the Interim Examination and Maintenance (IEM Cell) Facility of the FFTF Flux Test.
Date: March 6, 2000
Creator: HILL, L.F.
Object Type: Report
System: The UNT Digital Library
Automated Critical Peak Pricing Field Tests: Program Descriptionand Results (open access)

Automated Critical Peak Pricing Field Tests: Program Descriptionand Results

California utilities have been exploring the use of critical peak prices (CPP) to help reduce needle peaks in customer end-use loads. CPP is a form of price-responsive demand response (DR). Recent experience has shown that customers have limited knowledge of how to operate their facilities in order to reduce their electricity costs under CPP (Quantum 2004). While the lack of knowledge about how to develop and implement DR control strategies is a barrier to participation in DR programs like CPP, another barrier is the lack of automation of DR systems. During 2003 and 2004, the PIER Demand Response Research Center (DRRC) conducted a series of tests of fully automated electric demand response (Auto-DR) at 18 facilities. Overall, the average of the site-specific average coincident demand reductions was 8% from a variety of building types and facilities. Many electricity customers have suggested that automation will help them institutionalize their electric demand savings and improve their overall response and DR repeatability. This report focuses on and discusses the specific results of the Automated Critical Peak Pricing (Auto-CPP, a specific type of Auto-DR) tests that took place during 2005, which build on the automated demand response (Auto-DR) research conducted through PIER and the …
Date: April 6, 2006
Creator: Piette, Mary Ann; Watson, David; Motegi, Naoya; Kiliccote, Sila & Xu, Peng
Object Type: Report
System: The UNT Digital Library
FY06 I/O Integration Blueprint (open access)

FY06 I/O Integration Blueprint

This document provides an understanding of the near and long term computing and I/O resources in the Secure Computing Facility (SCF) and Open Computing Facility (OCF). Requirements for data flows, storage capacities and transfer rates are determined. Recommendations are made for architectures, timeframes for major deliverables, and procurements for the next fiscal year.
Date: April 6, 2006
Creator: Cupps, K.; Fitzgerald, K.; Gary, M.; Shoopman, J.; Hamilton, P.; Loewe, B. et al.
Object Type: Report
System: The UNT Digital Library
Annual report to Congress on Federal Government energy management and conservation programs, Fiscal year 1994 (open access)

Annual report to Congress on Federal Government energy management and conservation programs, Fiscal year 1994

This report provides sinformation on energy consumption in Federal buildings and operations and documents activities conducted by Federal agencies to meet statutory requirements of the National Energy Conservation Policy Act. It also describes energy conservation and management activities of the Federal Government under section 381 of the Energy Policy and Conservation Act. Implementation activities undertaken during FY94 by the Federal agencies under the Energy Policy Act of 1992 and Executive Orders 12759 and 12902 are also described. During FY94, total (gross) energy consumption of the US Government, including energy consued to produce, process, and transport energy, was 1.72 quadrillion Btu. This represents {similar_to}2.0% of the total 85.34 quads used in US.
Date: October 6, 1995
Creator: unknown
Object Type: Report
System: The UNT Digital Library
AnisWave2D: User's Guide to the 2d Anisotropic Finite-DifferenceCode (open access)

AnisWave2D: User's Guide to the 2d Anisotropic Finite-DifferenceCode

This document describes a parallel finite-difference code for modeling wave propagation in 2D, fully anisotropic materials. The code utilizes a mesh refinement scheme to improve computational efficiency. Mesh refinement allows the grid spacing to be tailored to the velocity model, so that fine grid spacing can be used in low velocity zones where the seismic wavelength is short, and coarse grid spacing can be used in zones with higher material velocities. Over-sampling of the seismic wavefield in high velocity zones is therefore avoided. The code has been implemented to run in parallel over multiple processors and allows large-scale models and models with large velocity contrasts to be simulated with ease.
Date: January 6, 2005
Creator: Toomey, Aoife
Object Type: Report
System: The UNT Digital Library
Interaction of Nocturnal Low-Level Jets with Urban Geometries as seen in Joint URBAN 2003 Data (open access)

Interaction of Nocturnal Low-Level Jets with Urban Geometries as seen in Joint URBAN 2003 Data

As accurate modeling of atmospheric flows in urban environments requires sophisticated representation of complex urban geometries, much work has been devoted to treatment of the urban surface. However, the importance of the larger-scale flow impinging upon the urban complex to the flow, transport and dispersion within it and downwind has received less attention. Building-resolving computational fluid dynamics (CFD) models are commonly employed to investigate interactions between the flow and three-dimensional structures comprising the urban environment, however such models are typically forced with simplified boundary conditions that fail to include important regional-scale phenomena that can strongly influence the flow within the urban complex and downwind. This paper investigates the interaction of an important and frequently occurring regional-scale phenomenon, the nocturnal low-level jet (LLJ), with urban-scale turbulence and dispersion in Oklahoma City using data from the Joint URBAN 2003 (JU2003) field experiment. Two simulations of nocturnal tracer release experiments from JU2003 using Lawrence Livermore National laboratory's FEM3MP CFD model yield differing levels of agreement with the observations in wind speed, turbulence kinetic energy (TKE) and concentration profiles in the urban wake, approximately 750m downwind of the central business district. Profiles of several observed turbulence parameters at this location indicate characteristics of both …
Date: September 6, 2006
Creator: Lundquist, J. K. & Mirocha, J. D.
Object Type: Article
System: The UNT Digital Library
Performance assurance program plan (open access)

Performance assurance program plan

B and W Protec, Inc. (BWP) is responsible for implementing the Performance Assurance Program for the Project Hanford Management Contract (PHMC) in accordance with DOE Order 470.1, Safeguards and Security Program (DOE 1995a). The Performance Assurance Program applies to safeguards and security (SAS) systems and their essential components (equipment, hardware, administrative procedures, Protective Force personnel, and other personnel) in direct support of Category I and H special nuclear material (SNM) protection. Performance assurance includes several Hanford Site activities that conduct performance, acceptance, operability, effectiveness, and validation tests. These activities encompass areas of training, exercises, quality assurance, conduct of operations, total quality management, self assessment, classified matter protection and control, emergency preparedness, and corrective actions tracking and trending. The objective of the Performance Assurance Program is to capture the critical data of the tests, training, etc., in a cost-effective, manageable program that reflects the overall effectiveness of the program while minimizing operational impacts. To aid in achieving this objective, BWP will coordinate the Performance Assurance Program for Fluor Daniel Hanford, Inc. (FDH) and serve as the central point for data collection.
Date: November 6, 1997
Creator: Rogers, B. H.
Object Type: Report
System: The UNT Digital Library
Coral Radiocarbon Records of Indian Ocean Water Mass Mixing and Wind-Induced Upwelling Along the Coast of Sumatra, Indonesia (open access)

Coral Radiocarbon Records of Indian Ocean Water Mass Mixing and Wind-Induced Upwelling Along the Coast of Sumatra, Indonesia

Radiocarbon ({sup 14}C) in the skeletal aragonite of annually banded corals track radiocarbon concentrations in dissolved inorganic carbon (DIC) in surface seawater. As a result of nuclear weapons testing in the 1950s, oceanic uptake of excess {sup 14}C in the atmosphere has increased the contrast between surface and deep ocean {sup 14}C concentrations. We present accelerator mass spectrometric (AMS) measurements of radiocarbon isotope ({Delta}{sup 14}C) in Porites corals from the Mentawai Islands, Sumatra (0 S, 98 E) and Watamu, Kenya (3 S, 39 E) to document the temporal and spatial evolution of the {sup 14}C gradient in the tropical Indian Ocean. The rise in {Delta}{sup 14}C in the Sumatra coral, in response to the maximum in nuclear weapons testing, is delayed by 2-3 years relative to the rise in coral {Delta}{sup 14}C from the coast of Kenya. Kenya coral {Delta}{sup 14}C values rise quickly because surface waters are in prolonged contact with the atmosphere. In contrast, wind-induced upwelling and rapid mixing along the coast of Sumatra entrains {sup 14}C-depleted water from the subsurface, which dilutes the effect of the uptake of bomb-laden {sup 14}C by the surface-ocean. Bimonthly AMS {Delta}{sup 14}C measurements on the Mentawai coral reveal mainly interannual variability …
Date: February 6, 2004
Creator: Guilderson, T. P.; Grumet, N. S.; Abram, N. J.; Beck, J. W.; Dunbar, R. B.; Gagan, M. K. et al.
Object Type: Article
System: The UNT Digital Library