En este paper publicado en Water Resources Research evaluamos los patrones de uso de agua local y no local en el oeste de EEUU, la trasferencia e importación de agua entre estados así como también del uso de acuíferos profundos.
Este paper representa una colaboración entre hidrólogos, geólogos, biólogos y antropólogos forenses interesados en entender mejor la señal isotópica del agua para consumo humano en EEUU.
Patterns of local and nonlocal water resource use across the western U.S. determined via stable isotope intercomparisons
Stephen P. Good, Casey D. Kennedy, Jeremy C. Stalker, Lesley A. Chesson, Luciano O. Valenzuela, Melanie M. Beasley, James R. Ehleringer, Gabriel. J. Bowen.
Abstract:
In the western U.S., the mismatch between public water demands and natural water availability necessitates large interbasin transfers of water as well as groundwater mining of fossil aquifers. Here we identify probable situations of nonlocal water use in both space and time based on isotopic comparisons between tap waters and potential water resources within hydrologic basins. Our approach, which considers evaporative enrichment of heavy isotopes during storage and distribution, is used to determine the likelihood of local origin for 612 tap water samples collected from across the western U.S. We find that 64% of samples are isotopically distinct from precipitation falling within the local hydrologic basin, a proxy for groundwater with modern recharge, and 31% of samples are isotopically distinct from estimated surface water found within the local basin. Those samples inconsistent with local water sources, which we suggest are likely derived from water imported from other basins or extracted from fossil aquifers, are primarily clustered in southern California, the San Francisco Bay area, and central Arizona. Our isotope-based estimates of nonlocal water use are correlated with both hydrogeomorphic and socioeconomic properties of basins, suggesting that these factors exert a predictable influence on the likelihood that nonlocal waters are used to supply tap water. We use these basin properties to develop a regional model of nonlocal water resource use that predicts (r2 = 0.64) isotopically inferred patterns and allows assessment of total interbasin transfer and/or fossil aquifer extraction volumes across the western U.S.
DOI: 10.1002/2014WR015884
viernes, 24 de octubre de 2014
viernes, 17 de octubre de 2014
Paper Nuevo: Isótopos Estables, dieta y antropometría
En este paper publicado en el American journal of Human Biology presentamos un estudio sobre las diferencias en la dieta, las medidas corporales (obesidad) y los isótopos estables en mujeres de distintos estratos socio-económicos de Cali, Colombia, y evaluamos las relaciones entre estas variables.
Este trabajo forma parte de la tesis doctoral de Richard Bender y es su primer artículo publicado como primer autor! Análisis preliminares de estos datos fueron presentados en dos oportunidades en las reuniones de la American Association of Physical Anthropologists y en una oportunidad Richard ganó el premio "The Juan Comas Prize" (Stable isotopes (13C and 15N) track socioeconomic differences among urban Colombian women) otorgado por la mencionada asociación.
"Stable isotopes (carbon, nitrogen, sulfur), diet, and anthropometry in urban Colombian women: Investigating socioeconomic differences"
Richard L. Bender, Darna L. Dufour, Luciano O. Valenzuela, Thure E. Cerling, Matt Sponheimer, Julio C. Reina, James R. Ehleringer.
Abstract:
We conducted stable isotope and dietary analyses of women from higher and lower socioeconomic status (SES) groups in Cali, Colombia. The objectives were to test between-group differences in stable isotope, dietary, and anthropometric characteristics, and to evaluate relationships between diet and stable isotope values. Hair samples from 38 women (mean age 33.4) from higher and lower SES groups were analyzed for δ13C, δ15N, and δ34S values. Dietary intake was assessed via 24-h recalls. Anthropometric variables measured were body mass index, five body circumferences, and six skinfold thicknesses. Mean δ13C and δ15N values of the higher SES group (−16.4 and 10.3‰) were significantly greater than those of the lower SES group (−17.2 and 9.6‰; P < 0.01), but mean δ34S values did not differ significantly between groups (higher SES: 4.6‰; lower SES: 5.1‰). The higher SES group consumed a greater percentage of protein than the lower SES group (14% vs. 12% of energy; P = 0.03), but the groups did not differ in other dietary characteristics or in anthropometric characteristics. δ13C, δ15N, and δ34S values were not correlated with intake of the dietary items predicted (sugars, animal-source protein, and marine foods, respectively). The lower SES group was more variable in all three stable isotope values (P < 0.05), mirroring a trend toward greater dietary variability in this group. Stable isotope values revealed a difference between SES groups that was not explained by the dietary data. The relationship between diet and stable isotope composition is complex.
Este trabajo forma parte de la tesis doctoral de Richard Bender y es su primer artículo publicado como primer autor! Análisis preliminares de estos datos fueron presentados en dos oportunidades en las reuniones de la American Association of Physical Anthropologists y en una oportunidad Richard ganó el premio "The Juan Comas Prize" (Stable isotopes (13C and 15N) track socioeconomic differences among urban Colombian women) otorgado por la mencionada asociación.
"Stable isotopes (carbon, nitrogen, sulfur), diet, and anthropometry in urban Colombian women: Investigating socioeconomic differences"
Richard L. Bender, Darna L. Dufour, Luciano O. Valenzuela, Thure E. Cerling, Matt Sponheimer, Julio C. Reina, James R. Ehleringer.
Abstract:
We conducted stable isotope and dietary analyses of women from higher and lower socioeconomic status (SES) groups in Cali, Colombia. The objectives were to test between-group differences in stable isotope, dietary, and anthropometric characteristics, and to evaluate relationships between diet and stable isotope values. Hair samples from 38 women (mean age 33.4) from higher and lower SES groups were analyzed for δ13C, δ15N, and δ34S values. Dietary intake was assessed via 24-h recalls. Anthropometric variables measured were body mass index, five body circumferences, and six skinfold thicknesses. Mean δ13C and δ15N values of the higher SES group (−16.4 and 10.3‰) were significantly greater than those of the lower SES group (−17.2 and 9.6‰; P < 0.01), but mean δ34S values did not differ significantly between groups (higher SES: 4.6‰; lower SES: 5.1‰). The higher SES group consumed a greater percentage of protein than the lower SES group (14% vs. 12% of energy; P = 0.03), but the groups did not differ in other dietary characteristics or in anthropometric characteristics. δ13C, δ15N, and δ34S values were not correlated with intake of the dietary items predicted (sugars, animal-source protein, and marine foods, respectively). The lower SES group was more variable in all three stable isotope values (P < 0.05), mirroring a trend toward greater dietary variability in this group. Stable isotope values revealed a difference between SES groups that was not explained by the dietary data. The relationship between diet and stable isotope composition is complex.
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