Tamborski Joseph

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Last Name
Tamborski
First Name
Joseph
ORCID
0000-0003-2422-3252

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Now showing 1 - 4 of 4
  • Article
    Radium isotopes as submarine groundwater discharge (SGD) tracers: review and recommendations
    (Elsevier, 2021-05-14) Garcia-Orellana, Jordi ; Rodellas, Valenti ; Tamborski, Joseph ; Diego-Feliu, Marc ; van Beek, Pieter ; Weinstein, Yishai ; Charette, Matthew A. ; Alorda-Kleinglass, Aaron ; Michael, Holly A. ; Stieglitz, Thomas ; Scholten, Jan C.
    Submarine groundwater discharge (SGD) is now recognized as an important process of the hydrological cycle worldwide and plays a major role as a conveyor of dissolved compounds to the ocean. Naturally occurring radium isotopes (223Ra, 224Ra, 226Ra and 228Ra) are widely employed geochemical tracers in marine environments. Whilst Ra isotopes were initially predominantly applied to study open ocean processes and fluxes across the continental margins, their most common application in the marine environment has undoubtedly become the identification and quantification of SGD. This review focuses on the application of Ra isotopes as tracers of SGD and associated inputs of water and solutes to the coastal ocean. In addition, we review i) the processes controlling Ra enrichment and depletion in coastal groundwater and seawater; ii) the systematics applied to estimate SGD using Ra isotopes and iii) we summarize additional applications of Ra isotopes in groundwater and marine studies. We also provide some considerations that will help refine SGD estimates and identify the critical knowledge gaps and research needs related to the current use of Ra isotopes as SGD tracers.
  • Article
    Conceptual uncertainties in groundwater and porewater fluxes estimated by radon and radium mass balances
    (Association for the Sciences of Limnology and Oceanography, 2021-01-08) Rodellas, Valenti ; Stieglitz, Thomas ; Tamborski, Joseph ; van Beek, Pieter ; Andrisoa, Aladin ; Cook, Peter G.
    Radium isotopes and radon are routinely used as tracers to quantify groundwater and porewater fluxes into coastal and freshwater systems. However, uncertainties associated with the determination of the tracer flux are often poorly addressed and often neglect all the potential errors associated with the conceptualization of the system (i.e., conceptual uncertainties). In this study, we assess the magnitude of some of the key uncertainties related to the determination of the radium and radon inputs supplied by groundwater and porewater fluxes into a waterbody (La Palme Lagoon, France). This uncertainty assessment is addressed through a single model ensemble approach, where a tracer mass balance is run multiple times with variable sets of assumptions and approaches for the key parameters determined through a sensitivity test. In particular, conceptual uncertainties linked to tracer concentration, diffusive fluxes, radon evasion to the atmosphere, and change of tracer inventory over time were considered. The magnitude of porewater fluxes is further constrained using a comparison of independent methods: (1) 224Ra and (2) 222Rn mass balances in overlying waters, (3) a model of 222Rn deficit in sediments, and (4) a fluid‐salt numerical transport model. We demonstrate that conceptual uncertainties are commonly a major source of uncertainty on the estimation of groundwater or porewater fluxes and they need to be taken into account when using tracer mass balances. In the absence of a general framework for assessing these uncertainties, this study provides a practical approach to evaluate key uncertainties associated to radon and radium mass balances.
  • Article
    Guidelines and limits for the quantification of ra isotopes and related radionuclides with the radium delayed coincidence counter (RaDeCC)
    (American Geophysical Union, 2020-03-27) Diego-Feliu, Marc ; Rodellas, Valenti ; Alorda-Kleinglass, Aaron ; Tamborski, Joseph ; van Beek, Pieter ; Heins, L. ; Bruach, Joan Manuel ; Arnold, Ralph ; Garcia-Orellana, Jordi
    The Radium Delayed Coincidence Counter (RaDeCC) is one of the most extensively used equipment for measuring 223Ra and 224Ra activities in water and sediment samples. Samples are placed in a closed He‐circulation system that carries the Rn produced by the decay of Ra to a scintillation cell. Each alpha decay recorded in the cell is routed to an electronic delayed coincidence system which enables the discrimination of 223Ra and 224Ra. In this study, the measurement and quantification methods using the RaDeCC system are assessed through analyses of registered data in different RaDeCC systems worldwide and a set of simulations. Results of this work indicate that the equations used to correct for 223Ra and 224Ra cross‐talk interferences are only valid for a given range of activities and ratios between isotopes. Above certain limits that are specified in this study, these corrections may significantly overestimate the quantification of 223Ra and 224Ra activities (up to ~40% and 30%, respectively), as well as the quantification of their parents 227Ac and 228Th. High activities of 226Ra may also produce an overestimation of 224Ra activities due to the buildup of 222Rn, especially when long measurements with low activities of 224Ra are performed. An improved method to quantify 226Ra activities from the buildup of 222Rn with the RaDeCC system is also developed in this study. Wethus provide a new set of guidelines for the appropriate quantification of 223Ra, 224Ra, 227Ac, 228Th, and 226Ra with the RaDeCC system.
  • Article
    Nutrient fluxes associated with submarine groundwater discharge from karstic coastal aquifers (Côte Bleue, French Mediterranean coastline)
    (Frontiers Media, 2020-02-18) Bejannin, Simon ; Tamborski, Joseph ; van Beek, Pieter ; Souhaut, Marc ; Stieglitz, Thomas ; Radakovitch, Olivier ; Claude, Christelle ; Conan, Pascal ; Pujo-Pay, Mireille ; Crispi, Olivier ; Le Roy, Emilie ; Estournel, Claude
    Determination of submarine groundwater discharge (SGD) from karstic coastal aquifers is important to constrain hydrological and biogeochemical cycles. However, SGD quantification using commonly employed geochemical methods can be difficult to constrain under the presence of large riverine inputs, and is further complicated by the determination of the karstic groundwater endmember. Here, we investigated a coastal region where groundwater discharges from a karstic aquifer system using airborne thermal infrared mapping and geochemical sampling conducted along offshore transects. We report radium data (223Ra, 224Ra, 228Ra) that we used to derive fluxes (water, nutrients) associated with terrestrial groundwater discharge and/or seawater circulation through the nearshore permeable sediments and coastal aquifer. Field work was conducted at different periods of the year to study the temporal variability of the chemical fluxes. Offshore transects of 223Ra and 224Ra were used to derive horizontal eddy diffusivity coefficients that were subsequently combined with surface water nutrient gradients (NO2− + NO3−, DSi) to determine the net nutrient fluxes from SGD. The estimated DSi and (NO2− + NO3−) fluxes are 6.2 ± 5.0 *103 and 4.0 ± 2.0 *103 mol d−1 per km of coastline, respectively. We attempted to further constrain these SGD fluxes by combining horizontal eddy diffusivity and 228Ra gradients. However, SGD endmember selection in this area (terrestrial groundwater discharge vs. porewater) adds further uncertainty to the flux calculation and thus prevented us from calculating a reliable flux using this latter method. Additionally, the relatively long half-life of 228Ra (5.75 y) makes it sensitive to specific circulation patterns in this coastal region, including sporadic intrusions of Rhône river waters that impact both the 228Ra and nutrient surface water distributions. We show that SGD nutrient fluxes locally reach up to 20 times the nutrient fluxes from a small river (Huveaune River). On a regional scale, DSi fluxes driven by SGD vary between 0.1 and 1.4% of the DSi inputs of the Rhône River, while the (NO2− + NO3−) fluxes driven by SGD on this 22 km long coastline are between 0.1 and 0.3% of the Rhône River inputs, the largest river that discharges into the Mediterranean Sea. Interestingly, the nutrient fluxes reported here are similar in magnitude compared with the fluxes quantified along the sandy beach of La Franqui, in the western Gulf of Lions (Tamborski et al., 2018), despite the different lithology of the two areas (karst systems vs. unconsolidated sediment).