IACT - Artículoshttps://hdl.handle.net/10481/492012024-03-28T09:12:28Z2024-03-28T09:12:28ZTrophic Ecology during the Ontogenetic Development of the Pelagic Thresher Shark Alopias pelagicus in Baja California Sur, MexicoSánchez-Latorre, ClaraDelgado Huertas, Antoniohttps://hdl.handle.net/10481/861012023-12-11T13:34:01ZTrophic Ecology during the Ontogenetic Development of the Pelagic Thresher Shark Alopias pelagicus in Baja California Sur, Mexico
Sánchez-Latorre, Clara; Delgado Huertas, Antonio
The trophic ecology of the Pelagic Thresher shark (Alopias pelagicus) was evaluated based on chemical ecology using stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) in the vertebrae and muscles. Individuals were caught between August 2013 and October 2019 on both the coasts of Baja California Sur, Mexico. In Bahía Tortugas, the mean vertebrae (n = 35) values were 12.72 ± 1.06‰ (δ15N) and −14.79 ± 0.61‰ (δ13C), while in muscles (n = 32) these values were 16.63 ± 0.76‰ (δ15N) and −17.18 ± 0.39‰ (δ13C). In Santa Rosalía, the mean vertebrae (n = 125) isotopic values were 14.4 ± 1.59‰ (δ15N) and −14.18 ± 0.51‰ (δ13C), while in muscles (n = 43), these values were 18.08 ± 0.96‰ (δ15N) and −16.43 ± 0.34‰ (δ13C). These results show higher δ15N values in Santa Rosalía as an effect of baseline isotopic differences between the two regions, whereas the δ13C values were lower in Bahía Tortugas, suggesting offshore ecological behavior (p < 0.05). In Santa Rosalía, there were significant differences by sex for δ15N in muscle, whereas the δ13C showed ontogenetic shifts, indicating that neonates feed in coastal areas more commonly than juveniles or adults (p < 0.05). Neither sex nor ontogenetic differences were observed in Bahía Tortugas (p > 0.05), suggesting a high overlap between their isotopic niches. Therefore, Alopias pelagicus uses the same ecological niche throughout its life, and there is consistency between sexes. The mean trophic position for both tissues and regions was 4.5, which corresponds to a tertiary predator, without any differences between stages or sex. Due to their higher energetic needs, juveniles and females showed the greatest isotopic niche amplitude; thus, their ecological niche is the widest.
Computational assessment of the potential of cross-catalytic coprecipitating systems for the bottom-up design of nanocompositesRouillard, J.Maier, BrittaCölfen, HelmutGarcía Ruiz, Juan Manuelhttps://hdl.handle.net/10481/858902023-11-28T10:09:07ZComputational assessment of the potential of cross-catalytic coprecipitating systems for the bottom-up design of nanocomposites
Rouillard, J.; Maier, Britta; Cölfen, Helmut; García Ruiz, Juan Manuel
The production of nanocomposites is often economically and environmentally costly. Silica-witherite
biomorphs, known for producing a wealth of life-like shapes, are nanocomposites entirely formed
through self-organization processes. Behind these precipitates are two precipitation reactions that
catalyze each other. Using a simple computational approach, we show here that this type of chemical
system – defined here as Cross-Catalytic Coprecipitating Systems (CCCSs) – is of great interest to
material design. Provided that cross-catalytic effects are sufficient to overcome the precipitation
thresholds for each phase, all CCCSs can be expected to self-organize into nanocomposite materials
through a one-pot, one-step synthesis protocol. Symmetry-breaking events generating various complex,
ordered textures are predicted in CCCSs involving crystalline phases. While high levels of stochasticity
lead to a loss of ordering, coprecipitation is found to be robust to diffusion or advection in the solution.
This model shows that a couple of chemical reactions can generate a range of complex textures – with
possibly distinct physical/chemical properties. Cross-catalytic coprecipitating systems consequently
represent a promising avenue for producing nanocomposites with complex textures at reduced
economic and environmental costs.
Arms and the mollusc: An evolutionary arms race has produced armor based on molluscan biomineralizationCartwright, Julyan H. E.Checa González, Antonio G.Vendrasco, Michael J.https://hdl.handle.net/10481/854162023-11-28T23:15:22ZArms and the mollusc: An evolutionary arms race has produced armor based on molluscan biomineralization
Cartwright, Julyan H. E.; Checa González, Antonio G.; Vendrasco, Michael J.
More than half a billion years ago in the early Cambrian period, there began an evolutionary arms race between molluscs and their predators, in which molluscs developed armor in the form of a biomineral exoskeleton—a shell—to avoid being eaten by predators that were developing jaws and other novel means of devouring them. The mollusc fabricates multiple layers of shell, each of a particular microstructure of a composite between an inorganic and an organic phase, which are the end result of more than 500 million years of coevolution with increasingly deadly predators. Molluscan biomineralization is an excellent case to study how a biological process produces a complex structure, because the shell is constructed as an extracellular structure in which all construction materials are passed out of the cells to self-assemble outside the cell wall. We consider what is known of the development of multilayer composite armor in the form of nacre (mother of pearl) and the other strong microstructures with which molluscs construct their shells.
A.G.C. acknowledges funding from Project No. PID2020116660GB-I00, funded by Spanish Ministry of Science and Innovation (MCIN/AEI/10.13039/ 501100011033).
Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature.
Evidence for liquid-liquid phase separation during the early stages of Mg-struvite formationKarafiludis, StephanosVan Driessche, Alexander Edgard Suzannehttps://hdl.handle.net/10481/854062023-11-02T10:18:44ZEvidence for liquid-liquid phase separation during the early stages of Mg-struvite formation
Karafiludis, Stephanos; Van Driessche, Alexander Edgard Suzanne
The precipitation of struvite, a magnesium ammonium phosphate hexahydrate (MgNH4PO4 · 6H2O) mineral, from wastewater is a promising method for recovering phosphorous. While this process is commonly used in engineered environments, our understanding of the underlying mechanisms responsible for the formation of struvite crystals remains limited. Specifically, indirect evidence suggests the involvement of an amorphous precursor and the occurrence of multi-step processes in struvite formation, which would indicate non-classical paths of nucleation and crystallization. In this study, we use synchrotron-based in situ x-ray scattering complemented by cryogenic transmission electron microscopy to obtain new insights from the earliest stages of struvite formation. The holistic scattering data captured the structure of an entire assembly in a time-resolved manner. The structural features comprise the aqueous medium, the growing struvite crystals, and any potential heterogeneities or complex entities. By analysing the scattering data, we found that the onset of crystallization causes a perturbation in the structure of the surrounding aqueous medium. This perturbation is characterized by the occurrence and evolution of Ornstein-Zernike fluctuations on a scale of about 1 nm, suggesting a non-classical nature of the system. We interpret this phenomenon as a liquid-liquid phase separation, which gives rise to the formation of the amorphous precursor phase preceding actual crystal growth of struvite. Our microscopy results confirm that the formation of Mg-struvite includes a short-lived amorphous phase, lasting >10 s.
We thank BAM and Helmholtz-Zentrum Berlin (HZB) for providing us with the beamtime at mySpot of BESSY II.; The supplementary material document file contains the following items: Fig. S1. The time-resolved pH curve from the struvite
precipitation reaction [Eq. (1)] combined with PHREEQC calculated equilibrated pH; Fig. S2. Cryo-TEM bright-field imaging from
the reactant solution sampled after 5 s after mixing without any
post-processing. Fig. S3. Sketch of the flow-through setup used for
the scattering experiments; Supporting Note 1: We derive how the
OZ correlation length compares with an equivalent radius of a
sphere.
We also include input (MgStruvite_01_input.pqi) and output
(MgStruvite_output.pqo) files from PHREEQC 3, which contain
information about the predicted speciation at equilibrium following the reaction from Eq. (1). These are regular text files and are
human-readable.
Drought as a possible contributor to the Visigothic Kingdom crisis and Islamic expansion in the Iberian PeninsulaCamuera, JonJiménez-Espejo, Francisco JoséSoto Chica, JoséJiménez Moreno, GonzaloGarcía-Alix Daroca, Antoniohttps://hdl.handle.net/10481/853782023-11-28T23:14:45ZDrought as a possible contributor to the Visigothic Kingdom crisis and Islamic expansion in the Iberian Peninsula
Camuera, Jon; Jiménez-Espejo, Francisco José; Soto Chica, José; Jiménez Moreno, Gonzalo; García-Alix Daroca, Antonio
The Muslim expansion in the Mediterranean basin was one the most relevant and rapid cultural changes in human history. This expansion reached the Iberian Peninsula with the replacement of the Visigothic Kingdom by the Muslim Umayyad Caliphate and the Muslim Emirate of Córdoba during the 8th century CE. In this study we made a compilation of western Mediterranean pollen records to gain insight about past climate conditions when this expansion took place. The pollen stack results, together with other paleohydrological records, archaeological data and historical sources, indicate that the statistically significant strongest droughts between the mid-5th and mid-10th centuries CE (450–950 CE) occurred at 545–570, 695–725, 755–770 and 900–935 CE, which could have contributed to the instability of the Visigothic and Muslim reigns in the Iberian Peninsula. Our study supports the great sensitivity of the agriculture-based economy and socio-political unrest of Early Medieval kingdoms to climatic variations