Stable oxygen isotopes reveal habitat use by marine mammals in the Río de la Plata estuary and adjoining Atlantic Ocean

Drago, Massimiliano; Valdivia, Meica; Bragg, Daniel M.; González, Enrique M.; Aguilar, Àlex; Cardona, Luís

doi:10.1016/j.ecss.2020.106708

Cited by 13 publications

(17 citation statements)

References 91 publications

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“…Other isotopic systems have also been used, including sulfur as a proxy for foraging ecology (Szpak and Buckley, 2020) and zinc for trophic level in archeological arctic marine mammal bone (Jaouen et al, 2016;McCormack et al, 2021). Oxygen isotopes in marine systems have been used to identify habitat use (Clementz and Koch, 2001;Drago et al, 2020). Guy et al (2018) used oxygen isotopes to identify fish from a hypersaline lagoon environment in northern Egypt and are able to identify a period of intense exploitation, and trade based on the isotopic signature.…”

Section: Stable Isotopesmentioning

confidence: 99%

Shifting Baselines to Thresholds: Reframing Exploitation in the Marine Environment

2021

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Current research on anthropogenic impacts on marine ecosystems often relies on the concept of a “baseline,” which aims to describe ecosystems prior to human contact. Recent research is increasingly showing that humans have been involved in marine ecosystems for much longer than previously understood. We propose a theoretical framework oriented around a system of “thresholds” referring to system-wide changes in human culture, ecosystem dynamics, and molecular evolution. The concept of the threshold allows conceptual space to account for the fluid nature of ecosystems throughout time while providing a critical framework for understanding drivers of ecosystem change. We highlight practical research approaches for exploring thresholds in the past and provide key insights for future adaptation to a changing world. To ensure ecological and societal goals for the future are met, it is critical that research efforts are contextualized into a framework that incorporates human society as integral to ecology and evolution.

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Section: Stable Isotopesmentioning

confidence: 99%

Shifting Baselines to Thresholds: Reframing Exploitation in the Marine Environment

2021

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“…On the contrary, the Fraser's dolphin is a poorly studied species, although the scarce information available suggests an oceanic niche (Dolar 2018;Drago et al 2021). Moreover, the habitat preferences of false killer whales, franciscana dolphins and Burmeister's porpoises in the region, are not completely understood, because contradictory information has been reported in the literature about their distribution in the estuary, and no good model of habitat partitioning exists to date in the regions where they coexist (Baird 2018;Cárdenas-Alayza 2018b;Crespo 2018;Reyes 2018;Drago et al 2020Drago et al , 2021.…”

Section: Introductionmentioning

confidence: 99%

“…The stable isotopes of carbon (C) and nitrogen (N) are the most widely used elements in studies related to the trophic ecology of marine mammals, but the interest on the stable isotopes of sulfur (S) and oxygen (O) has increased recently (Rubenstein and Hobson 2004;Newsome et al 2010;Ramos and González-Solís 2012;Drago et al 2020;Borrell et al 2021). The C stable isotope ratio ( 13 C/ 12 C; δ 13 C) is informative about the primary source of carbon in a specific food web, mostly due to a different discrimination against the heavier 13 C isotope during photosynthesis between primary producers (Peterson and Howarth 1987;Michener and Lajtha 2007).…”

Section: Introductionmentioning

confidence: 99%

“…The δ 18 O values in the marine environment are positively and linearly correlated with the salinity of the water (Gat 1996;Conroy et al 2014), and therefore, it can be a useful habitat tracer in areas where an abundant freshwater input creates marked horizontal and vertical salinity gradients (Guerrero et al 1997;Conroy et al 2014;Belem et al 2019). The δ 18 O values in animal tissues often reflect with great precision those of the body of water where they feed (Yoshida and Miyazaki 1991;Ben-David and Flaherty 2012), allowing to discriminate between species with estuarine, coastal, and marine habits (Clementz and Koch 2001;Rubenstein and Hobson 2004;Newsome et al 2010;Matthews et al 2016;Drago et al 2020).…”

Section: Introductionmentioning

confidence: 99%

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Niche Partitioning Among Marine Mammals Inhabiting a Large Estuary as Revealed by Stable Isotopes of C, N, S, and O

Cani

Cardona

Valdivia³

et al. 2023

Estuaries and Coasts

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Detailed knowledge on habitat use by marine mammals is critical to understand their role in the ecosystem. The stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) have been widely used to study the trophic ecology of marine mammals, but the stable isotope ratios of other elements such as sulfur (δ34S) and oxygen (δ18O) can better inform about habitat use in areas with strong salinity and redox gradients. The Río de la Plata estuary represents the largest freshwater runoff in the south-western Atlantic Ocean and supports a rich community of marine mammals. Here, we analyzed δ34S values in bone from seven marine mammal species inhabiting the estuary and the adjacent Atlantic Ocean, in order to complement previous isotopic data (δ13C, δ15N and δ18O) and compare their resolution as habitat tracers. As expected, δ34S and δ18O offered relevant insights into the characterization of the habitat used by marine mammals and allowed a better delineation of habitat partitioning between them. Bottlenose dolphins, South American sea lions and South American fur seals seem to be frequent users of the less saline areas of the estuary, whereas Burmeister´s porpoises, franciscana dolphins and false killer whales seemed to prefer the saltier marine waters close to the bottom. Fraser´s dolphins were the only inhabitants of true offshore waters. Our findings demonstrate how the integration of different stable isotope ratios can help disentangle fine habitat partitioning between marine mammals living in a complex ecosystem such as Río de la Plata.

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“…The stable isotope ratios of sulfur ( 34 S/ 32 S, reported as δ 34 S), for example, can be combined with δ 13 C to help distinguish among primary producers in marine food webs (Connolly et al, 2004), and to identify foraging ranges and spatial distribution across populations (e.g., Giménez et al, 2018b; Wilson et al, 2012), between sexes, and among ages (e.g., Louis et al, 2021; Niño‐Torres et al, 2006). The stable isotope ratios of oxygen ( 18 O/ 16 O, reported as δ 18 O) are potentially useful to distinguish habitat use (e.g., Drago et al, 2020) and movements across areas with strong salinity gradients (e.g., Gauffier et al, 2020; Matthews et al, 2016). The stable isotope ratios of strontium ( 87 Sr/ 86 Sr ratios, reported as 87 Sr) vary regionally according to oceanographic factors and have been used to investigate movements patterns in mysticetes (e.g., Vighi et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

A practical guide on stable isotope analysis for cetacean research

Teixeira

Troina

Daura‐Jorge

et al. 2022

Marine Mammal Science

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Trophic ecology information about cetaceans is essential to understand their role in ecosystem dynamics. Stable isotope analysis is a valuable complementary approach to conventional methods usually applied to the study of the foraging behavior of cetaceans because it provides dietary information over different time scales and can potentially use tissues archived in scientific collections. However, the considerable increase in stable isotope analysis by a growing number of cetacean research groups demands the use of proper protocols to ensure that accurate isotopic data are obtained. We provide a theoretical background of stable isotope analysis and its application to assess cetaceans‘ trophic ecology. We review the factors that can influence isotopic measurements and propose a practical guideline with suitable techniques for sample preparation of biological tissues to be employed by researchers to yield reliability in the interpretation of isotopic data. We summarized the main assumptions and inherent limitations that can lead to confounding interpretations of isotopic data, such as species‐ and tissue‐specific discrimination factors, temporal or spatial variation in prey, and baseline isotopic values in the context of cetacean ecology. Our detailed review offers important guidance for researchers who want to use stable isotope analysis to address different ecological questions with cetacean species.

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Stable oxygen isotopes reveal habitat use by marine mammals in the Río de la Plata estuary and adjoining Atlantic Ocean

Cited by 13 publications

References 91 publications

Shifting Baselines to Thresholds: Reframing Exploitation in the Marine Environment

Shifting Baselines to Thresholds: Reframing Exploitation in the Marine Environment

Niche Partitioning Among Marine Mammals Inhabiting a Large Estuary as Revealed by Stable Isotopes of C, N, S, and O

A practical guide on stable isotope analysis for cetacean research

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