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Title: The influence of microbial activity and sedimentary organic carbon on the isotope geochemistry of the Middendorf aquifer

Abstract

In this study, tritium, {sup 14}C, and groundwater chemistry along three flow paths of the Middendorf aquifer in South Carolina were analyzed. The {sup 14}C ranged from 89% modern carbon (pmC) in the recharge zone to 9.9 pmC in the distal borehole. Carbon isotope analyses of particulate organic carbon from core sediments and groundwater chemistry were used to model the carbon chemistry; the groundwater ages obtained from {sup 14}C ranged from modern to 11,500 years B.P. The highest frequencies of occurrence, numbers, and diversity of aerobic and anaerobic bacteria were found in boreholes near the recharge zone where the calculated ages were < 1,000 years B.P. The transport of microorganisms from the recharge zone may be responsible for this distribution as well as the electron acceptors necessary to support this diverse community of bacteria. The presence of both aerobic heterotrophs and anaerobic sulfate- and iron-reducing bacteria in the core sediments suggested the occurrence of anaerobic microsites throughout this otherwise aerobic aquifer. The highest in situ microbial respiration rate, as determines by modeling, was found along a flow path near the recharge area. It is likely that the electron acceptors necessary for supporting a diverse microbial community are depleted by themore » time the groundwater residence time in the Middendorf aquifer exceeds several hundred years.« less

Authors:
; ; ; ;  [1];  [2];  [3]
  1. Pacific Northwest Lab., Richland, WA (United States)
  2. Westinghouse Savannah River Co., Aiken, SC (United States)
  3. Brookhaven National Lab., Upton, NY (United States)
Publication Date:
OSTI Identifier:
5149710
DOE Contract Number:  
AC06-76RL01830
Resource Type:
Journal Article
Journal Name:
Water Resources Research; (United States)
Additional Journal Information:
Journal Volume: 28:3; Journal ID: ISSN 0043-1397
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.; AQUIFERS; GEOCHEMISTRY; GROUND WATER; CONTAMINATION; ORGANIC COMPOUNDS; WATER CHEMISTRY; SOUTH CAROLINA; WATER POLLUTION; BACTERIA; BIODEGRADATION; CARBON 14 COMPOUNDS; MATHEMATICAL MODELS; TRACER TECHNIQUES; TRITIUM COMPOUNDS; CARBON COMPOUNDS; CHEMICAL REACTIONS; CHEMISTRY; DECOMPOSITION; DEVELOPED COUNTRIES; HYDROGEN COMPOUNDS; ISOTOPE APPLICATIONS; LABELLED COMPOUNDS; MICROORGANISMS; NORTH AMERICA; OXYGEN COMPOUNDS; POLLUTION; USA; WATER; 540220* - Environment, Terrestrial- Chemicals Monitoring & Transport- (1990-); 560300 - Chemicals Metabolism & Toxicology

Citation Formats

Murphy, E M, Schramke, J A, Fredrickson, J K, Sklarew, D S, Linehan, J C, Bledsoe, H W, and Francis, A J. The influence of microbial activity and sedimentary organic carbon on the isotope geochemistry of the Middendorf aquifer. United States: N. p., 1992. Web. doi:10.1029/91WR02678.
Murphy, E M, Schramke, J A, Fredrickson, J K, Sklarew, D S, Linehan, J C, Bledsoe, H W, & Francis, A J. The influence of microbial activity and sedimentary organic carbon on the isotope geochemistry of the Middendorf aquifer. United States. https://doi.org/10.1029/91WR02678
Murphy, E M, Schramke, J A, Fredrickson, J K, Sklarew, D S, Linehan, J C, Bledsoe, H W, and Francis, A J. 1992. "The influence of microbial activity and sedimentary organic carbon on the isotope geochemistry of the Middendorf aquifer". United States. https://doi.org/10.1029/91WR02678.
@article{osti_5149710,
title = {The influence of microbial activity and sedimentary organic carbon on the isotope geochemistry of the Middendorf aquifer},
author = {Murphy, E M and Schramke, J A and Fredrickson, J K and Sklarew, D S and Linehan, J C and Bledsoe, H W and Francis, A J},
abstractNote = {In this study, tritium, {sup 14}C, and groundwater chemistry along three flow paths of the Middendorf aquifer in South Carolina were analyzed. The {sup 14}C ranged from 89% modern carbon (pmC) in the recharge zone to 9.9 pmC in the distal borehole. Carbon isotope analyses of particulate organic carbon from core sediments and groundwater chemistry were used to model the carbon chemistry; the groundwater ages obtained from {sup 14}C ranged from modern to 11,500 years B.P. The highest frequencies of occurrence, numbers, and diversity of aerobic and anaerobic bacteria were found in boreholes near the recharge zone where the calculated ages were < 1,000 years B.P. The transport of microorganisms from the recharge zone may be responsible for this distribution as well as the electron acceptors necessary to support this diverse community of bacteria. The presence of both aerobic heterotrophs and anaerobic sulfate- and iron-reducing bacteria in the core sediments suggested the occurrence of anaerobic microsites throughout this otherwise aerobic aquifer. The highest in situ microbial respiration rate, as determines by modeling, was found along a flow path near the recharge area. It is likely that the electron acceptors necessary for supporting a diverse microbial community are depleted by the time the groundwater residence time in the Middendorf aquifer exceeds several hundred years.},
doi = {10.1029/91WR02678},
url = {https://www.osti.gov/biblio/5149710}, journal = {Water Resources Research; (United States)},
issn = {0043-1397},
number = ,
volume = 28:3,
place = {United States},
year = {Sun Mar 01 00:00:00 EST 1992},
month = {Sun Mar 01 00:00:00 EST 1992}
}