Luciano Oscar Valenzuela

Objectives: The main objective of the study is to characterize and test the hypothesis of a continuing trend toward homogenization in contemporary Argentine diet through stable isotope analysis, exploring regional variation in the context of globalized food systems. It is expected that the distribution of stable isotopes will exhibit a limited range of values but still display some heterogeneity that allows differentiation of dietary patterns by region. Methods: A total of 204 hair samples were collected from volunteer donors in Argentina and analyzed for the stable isotopes δ ¹³ C, δ ¹⁵ N, and δ ³⁴ S. Statistical analyses and isotopic niche modeling using Bayesian ellipses were performed to determine dietary differences between regions and geographical factors influencing the distribution of stable isotopes. The ranges of variations in dietary choices (omnivores, vegetarians, and vegans) were also characterized. Results: The analyses revealed significant differences in stable isotope values between regions, indicating that interregional heterogeneity in diet persists despite globalization and previous trends. Significant correlations were found between isotopic values and geographic variables. It was determined that δ ¹³ C and δ ¹⁵ N values vary significantly between omnivores, vegetarians, and vegans, allowing for the identification of differential consumption of proteins at an isotopic level. Conclusions: The study concludes that the contemporary Argentine dietary pattern is consistent with the global trend toward “delocalized” and “deseasonalized” diets, where global foods are produced locally. The study suggests that the homogenization process has not completely eliminated regional dietary particularities, as the effective incorporation into diets is mediated by cultural, economic, and logistical factors.

Introduction: Contemporary dietary and nutritional transitions are commonplace, but difficult to study directly. In Brazil, and Latin America, this generalized process, leading to current obesity and malnutrition problems, started more than four decades ago. Although body weight and food availability are used to measure changes, not much information on food consumption and nutrition exist. Stable isotope analysis allows for the study of modern individual diets because it reflects the proportional contribution of different foods, general dietary patterns, and the effect of metabolism. Furthermore, when samples from tissues reflecting different time points are used, it allows for the assessment of individual transitions.Objectives: To explore intra‐person isotopic variation for the first time in the Southern Hemisphere for modern humans, and examine the nutritional transition reported for Brazil in the past four decades.Materials: Stable carbon and nitrogen isotope values from 68 ¹⁴C‐dated bone samples (vertebra, occipital, parietal, femur) from 17 individuals born in 1963, from three cemeteries.Results: Data reflect chronologically ordered high intra‐individual δ¹⁵N variation tracking the dietary and nutrition transition over the last few decades, while no relationship between δ¹³C values and time was found. Vertebrae, reflecting diets from the mid 2000s, showed lower δ¹⁵N values than other bones reflecting the mid 1980s and early 1990s.Discussion: We show how different bones capture nutritional transitions over the lifespan of modern individuals. Nitrogen isotope values were lower in recent tissues as a consequence of the changes in the agri‐food industry and worldwide consumption patterns that have intensified in Latin America in the last decades.

Assessing environmental changes in Southern Ocean ecosystems is difficult due to its remoteness and data sparsity. Monitoring marine predators that respond rapidly to environmental variation may enable us to track anthropogenic effects on ecosystems. Yet, many long-term datasets of marine predators are incomplete because they are spatially constrained and/or track ecosystems already modified by industrial fishing and whaling in the latter half of the 20th century. Here, we assess the contemporary offshore distribution of a wide-ranging marine predator, the southern right whale (SRW, Eubalaena australis ), that forages on copepods and krill from ~30°S to the Antarctic ice edge (>60°S). We analyzed carbon and nitrogen isotope values of 1,002 skin samples from six genetically distinct SRW populations using a customized assignment approach that accounts for temporal and spatial variation in the Southern Ocean phytoplankton isoscape. Over the past three decades, SRWs increased their use of mid-latitude foraging grounds in the south Atlantic and southwest (SW) Indian oceans in the late austral summer and autumn and slightly increased their use of high-latitude (>60°S) foraging grounds in the SW Pacific, coincident with observed changes in prey distribution and abundance on a circumpolar scale. Comparing foraging assignments with whaling records since the 18th century showed remarkable stability in use of mid-latitude foraging areas. We attribute this consistency across four centuries to the physical stability of ocean fronts and resulting productivity in mid-latitude ecosystems of the Southern Ocean compared with polar regions that may be more influenced by recent climate change.

En este trabajo se presentan los resultados de la aplicación de diversas metodologías y técnicas de la bioarqueología sobre un conjunto de restos óseos de personas, que forman parte del acervo patrimonial del Museo Etnográfico Municipal Dámaso Arce, localizado en la ciudad de Olavarría (República Argentina). Los estudios incluyeron la estimación del sexo, la evaluación del estado de preservación e integridad del conjunto y la realización de análisis isotópicos para asociar los restos a posibles procedencias geográficas. La combinación de estos análisis y procedimientos con la indagación en los fondos documentales del museo y la investigación de archivo de la época permitieron, poner en condiciones óptimas estos materiales culturales delicados. De esta manera se los pudo adecuar a la normativa legal vigente sobre el manejo de restos humanos indígenas y los códigos internacionales de deontología de los museos.

We present the first isotopic results of camelids bones from two archaeological sites located in the north of Quebrada de Humahuaca (Jujuy, Argentina): Antumpa and Cóndor II. The aim of this work is to generate information about the exploitation and management of camelids in the Late Holocene. We present δ13C y δ15N values measured on bone collagen of archaeological camelids, which provides new and unique information for isotopic studies in this region. The δ13C and δ15N results suggest that the diet from archaeological camelid are compatible with the modern vegetation from northern of Quebrada de Humahuaca (below 3900 msnm). Furthermore, differences in δ13C values of camelids from both sites, which can be explained by the altitude in which they are located, and lack of variations in measurements of δ15N, were observed. Finally, the δ13C and δ15N values of camelids assigned to wild and domestic morphotypes are similar although don’t overlap within the same altitudinal level. En este trabajo se exponen los primeros resultados isotópicos de restos óseos de camélidos de dos sitios arqueológicos del norte de la quebrada de Humahuaca (Jujuy, Argentina): Antumpa (1900-1300 AP; 3300 msnm) y Cóndor II (1100-960 AP; 3810 msnm). El objetivo es generar información sobre la explotación y manejo de este recurso en una región y para un lapso temporal que cuentan con escasos datos isotópicos. Se presentan 11 pares de valores de δ13C y δ15N medidos sobre colágeno óseo de camélidos arqueológicos que aportan nueva información para los estudios isotópicos regionales. Los valores de δ13C obtenidos oscilan entre -18,3‰ y -14,0‰ (media = -16,2‰); y los de δ15N, entre 6,4‰ y 8,9‰ (media = 7,7‰). Se registraron diferencias en los valores de δ13C de camélidos de Antumpa y Cóndor II y ausencia de variaciones en las mediciones de δ15N que podrían explicarse por la distinta altitud entre los sitios estudiados, aunque no se descarta el factor temporal como fuente de variabilidad isotópica alternativa. Además, se registró una muy baja variación de los valores de δ13C y δ15N entre las especies de camélidos representadas, que deberá corroborarse en futuras investigaciones con la incorporación de nuevas muestras.

As species recover from exploitation, continued assessments of connectivity and population structure are warranted to provide information for conservation and management. This is particularly true in species with high dispersal capacity, such as migratory whales, where patterns of connectivity could change rapidly. Here we build on a previous long-term, large-scale collaboration on southern right whales (Eubalaena australis) to combine new (n_new) and published (n_pub) mitochondrial (mtDNA) and microsatellite genetic data from all major wintering grounds and, uniquely, the South Georgia (Islas Georgias del Sur: SG) feeding grounds. Specifically, we include data from Argentina (n_pub mtDNA/microsatellite = 208/46), Brazil (n_new mtDNA/microsatellite = 50/50), South Africa (n_new mtDNA/microsatellite = 66/77, n_pub mtDNA/microsatellite = 350/47), Chile–Peru (n_new mtDNA/microsatellite = 1/1), the Indo-Pacific (n_pub mtDNA/microsatellite = 769/126), and SG (n_pub mtDNA/microsatellite = 8/0, n_new mtDNA/microsatellite = 3/11) to investigate the position of previously unstudied habitats in the migratory network: Brazil, SG, and Chile–Peru. These new genetic data show connectivity between Brazil and Argentina, exemplified by weak genetic differentiation and the movement of 1 genetically identified individual between the South American grounds. The single sample from Chile–Peru had an mtDNA haplotype previously only observed in the Indo-Pacific and had a nuclear genotype that appeared admixed between the Indo-Pacific and South Atlantic, based on genetic clustering and assignment algorithms. The SG samples were clearly South Atlantic and were more similar to the South American than the South African wintering grounds. This study highlights how international collaborations are critical to provide context for emerging or recovering regions, like the SG feeding ground, as well as those that remain critically endangered, such as Chile–Peru.