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Title: Spatial variations of scavenging rates within the central and northern Adriatic Sea: Use of U-Th disequilibria

Abstract

Dissolved and particulate concentrations of {sup 234}Th, {sup 210}Pb and {sup 210}Po were measured in surface waters of the central and northern Adriatic Sea. The half-lives and biogeochemistry of {sup 234}Th (t{sub 1/2} = 24.1 days), {sup 210}Po (t{sub 1/2} = 138.4 days) and {sup 210}Pb (t{sub 1/2} = 22.3 years) are ideal for studying particle dynamics in the upper water column. It has been observed that the residence time of dissolved {sup 234}Th with respect to removal on biogenic particles is inversely proportional to primary productivity and may be used to predict export from or new production in the euphotic zone. Model-derived {sup 234}Th fluxes can also be used to help validate sediment trap collections in the upper water column. The aim of the present study was to gain an insight into the intensity and variability of active scavenging and particle removal processes in the central and northern Adriatic Sea. This semi-enclosed sea is strongly influenced by fresh water runoff from rivers carrying large quantities of dissolved nutrients and suspended particles. These inputs of nutrients and suspended particles are expected to give rise to large biological and biogeochemical gradients across the Continental Shelf and offer a range of environmentsmore » for studying particle scavenging and removal processes. The authors have examined the relationships between {sup 234}Th scavenging rates and residence times of dissolved and particulate phases as a function of other physical and biological parameters (primary productivity, POC, chlorophyll, C/N and total suspended matter). Particular reference is made to the two contrasting environments of the Adriatic--a eutrophic zone near the Po River outflow and in the largely oligotrophic waters of the Jabuka Pit.« less

Authors:
 [1];  [2]; ;  [3]
  1. Lawrence Livermore National Lab., CA (United States)
  2. Danish Inst. for Fisheries and Marine Research, Charlottenlund (Denmark)
  3. IAEA Marine Environment Lab., Monaco (Monaco)
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE, Washington, DC (United States)
OSTI Identifier:
231454
Report Number(s):
UCRL-JC-123865; CONF-9604139-2
ON: DE96010833; TRN: AHC29611%%82
DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Conference
Resource Relation:
Conference: Institute for Electrical and Electronics Engineers (IEEE) metadata conference, Washington, DC (United States), 15-19 Apr 1996; Other Information: PBD: Apr 1996
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; ADRIATIC SEA; CONTAMINATION; THORIUM 234; RADIOECOLOGICAL CONCENTRATION; REMOVAL; LEAD 210; POLONIUM 210; RADIATION MONITORING; HALF-LIFE

Citation Formats

Hamilton, T, Heilmann, J, Fowler, S, and Miquel, J C. Spatial variations of scavenging rates within the central and northern Adriatic Sea: Use of U-Th disequilibria. United States: N. p., 1996. Web.
Hamilton, T, Heilmann, J, Fowler, S, & Miquel, J C. Spatial variations of scavenging rates within the central and northern Adriatic Sea: Use of U-Th disequilibria. United States.
Hamilton, T, Heilmann, J, Fowler, S, and Miquel, J C. 1996. "Spatial variations of scavenging rates within the central and northern Adriatic Sea: Use of U-Th disequilibria". United States. https://www.osti.gov/servlets/purl/231454.
@article{osti_231454,
title = {Spatial variations of scavenging rates within the central and northern Adriatic Sea: Use of U-Th disequilibria},
author = {Hamilton, T and Heilmann, J and Fowler, S and Miquel, J C},
abstractNote = {Dissolved and particulate concentrations of {sup 234}Th, {sup 210}Pb and {sup 210}Po were measured in surface waters of the central and northern Adriatic Sea. The half-lives and biogeochemistry of {sup 234}Th (t{sub 1/2} = 24.1 days), {sup 210}Po (t{sub 1/2} = 138.4 days) and {sup 210}Pb (t{sub 1/2} = 22.3 years) are ideal for studying particle dynamics in the upper water column. It has been observed that the residence time of dissolved {sup 234}Th with respect to removal on biogenic particles is inversely proportional to primary productivity and may be used to predict export from or new production in the euphotic zone. Model-derived {sup 234}Th fluxes can also be used to help validate sediment trap collections in the upper water column. The aim of the present study was to gain an insight into the intensity and variability of active scavenging and particle removal processes in the central and northern Adriatic Sea. This semi-enclosed sea is strongly influenced by fresh water runoff from rivers carrying large quantities of dissolved nutrients and suspended particles. These inputs of nutrients and suspended particles are expected to give rise to large biological and biogeochemical gradients across the Continental Shelf and offer a range of environments for studying particle scavenging and removal processes. The authors have examined the relationships between {sup 234}Th scavenging rates and residence times of dissolved and particulate phases as a function of other physical and biological parameters (primary productivity, POC, chlorophyll, C/N and total suspended matter). Particular reference is made to the two contrasting environments of the Adriatic--a eutrophic zone near the Po River outflow and in the largely oligotrophic waters of the Jabuka Pit.},
doi = {},
url = {https://www.osti.gov/biblio/231454}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Apr 01 00:00:00 EST 1996},
month = {Mon Apr 01 00:00:00 EST 1996}
}

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