Variación de isotopos estables (δ13C, δ15N) en huevos de anchoveta y sardina común entre años contrastantes frente a la desembocadura del río Itata.
Loading...
Date
2025
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Universidad de Concepción
Abstract
Cambios interanuales y de mayor escala, como el cambio climático, pueden alterar los patrones de precipitación, afectando la calidad y cantidad de materia orgánica que ingresa al océano, con potenciales repercusiones en las redes tróficas costeras.
Este estudio evaluó las variaciones interanuales en la composición isotópica (δ¹³C y δ¹⁵N) de huevos de anchoveta (Engraulis ringens) y sardina común (Strangomera bentincki) en la zona frente al río Itata, Chile, durante 2 años con condiciones contrastantes de caudal fluvial (2015: alto caudal; 2016: bajo caudal), considerando además el efecto del método de conservación de los huevos. Se integraron datos hidrográficos para contextualizar las diferencias ambos años y relacionar la señal isotópica con las condiciones del medio.
Se observaron diferencias significativas en δ¹³C, con valores más negativos en 2015, lo que sugiere un mayor aporte de materia orgánica terrestre durante años de mayor descarga fluvial. En cuanto a δ¹⁵N, solo los huevos de anchoveta presentaron variaciones significativas entre años, con valores mayores el año 2015, lo que señala un posible cambio en los patrones de alimentación y/o fuentes de nitrógeno para la base de red trófica. Se observó una clara relación entre estos cambios isotópicos y condiciones hidrográficas.
En base a los resultados se plantea la importancia de considerar la influencia de la variabilidad ambiental en la estructura trófica marina y ofrece bases más robustas para el desarrollo de estrategias de conservación y manejo sustentable de los recursos pesqueros, especialmente ante el escenario del cambio climático.
Trophic dynamics in coastal marine ecosystems are strongly influenced by physical and hydrological phenomena such as coastal upwelling and river discharge, which drive changes in environmental variables including temperature, salinity, dissolved oxygen concentration, density, and primary production. Interannual and larger-scale changes, such as those associated with climate change, can alter precipitation patterns, affecting the quality and quantity of organic matter entering the ocean, with potential repercussions for coastal food webs. This study evaluated interannual variations in the isotopic composition (δ¹³C and δ¹⁵N) of anchoveta (Engraulis ringens) and common sardine (Strangomera bentincki) eggs off the Itata River, Chile, over two years with contrasting river discharge conditions (2015: high discharge; 2016: low discharge), also considering the effect of egg preservation methods. Hydrographic data were integrated to contextualize interannual differences and to relate isotopic signals to environmental conditions. Significant differences in δ¹³C were observed, with more negative values in 2015, suggesting a greater contribution of terrestrial organic matter during years of higher fluvial input. Regarding δ¹⁵N, only anchoveta eggs showed significant interannual variation, with higher values in 2015, indicating a possible shift in feeding patterns and/or nitrogen sources at the base of the food web. A clear relationship was observed between these isotopic changes and hydrographic conditions. Based on these results, the study underscores the importance of considering the influence of environmental variability on marine trophic structure and provides a stronger foundation for the development of conservation strategies and the sustainable management of fishery resources, particularly in the context of climate change.
Trophic dynamics in coastal marine ecosystems are strongly influenced by physical and hydrological phenomena such as coastal upwelling and river discharge, which drive changes in environmental variables including temperature, salinity, dissolved oxygen concentration, density, and primary production. Interannual and larger-scale changes, such as those associated with climate change, can alter precipitation patterns, affecting the quality and quantity of organic matter entering the ocean, with potential repercussions for coastal food webs. This study evaluated interannual variations in the isotopic composition (δ¹³C and δ¹⁵N) of anchoveta (Engraulis ringens) and common sardine (Strangomera bentincki) eggs off the Itata River, Chile, over two years with contrasting river discharge conditions (2015: high discharge; 2016: low discharge), also considering the effect of egg preservation methods. Hydrographic data were integrated to contextualize interannual differences and to relate isotopic signals to environmental conditions. Significant differences in δ¹³C were observed, with more negative values in 2015, suggesting a greater contribution of terrestrial organic matter during years of higher fluvial input. Regarding δ¹⁵N, only anchoveta eggs showed significant interannual variation, with higher values in 2015, indicating a possible shift in feeding patterns and/or nitrogen sources at the base of the food web. A clear relationship was observed between these isotopic changes and hydrographic conditions. Based on these results, the study underscores the importance of considering the influence of environmental variability on marine trophic structure and provides a stronger foundation for the development of conservation strategies and the sustainable management of fishery resources, particularly in the context of climate change.
Description
Tesis presentada para optar al título de Biólogo/a Marino/a.
Keywords
Isótopos estables en investigación ecológica, Peces Huevos, Anchoveta, Sardinas