Instituto de Ciencias Naturales Alexander von Humboldt

URI permanente para esta colección

https://repositorioabierto.uantof.cl/handle/uantof/496

Examinar

Mostrando 1 - 20 de 31

Blowin’ in the Wind: Mapping the Dispersion of Metal(loid)s From Atacama Mining
(Advancing Earth and Space Sciences, 2024) Zanetta-Colombo, Nicolás, C.; Manzano, Carlos A.; Brombierstäudl, Dragmar; Fleming, Zoë L.; Gayo, Eugenia M.; Rubinos, David A.; Jerez, Óscar; Valdés, Jorge; Prieto, Manuel; Nüsser, Marcus
The Atacama Desert's naturally elevated metal(loid)s pose a unique challenge for assessing the environmental impact of mining, particularly for indigenous communities residing in these areas. This study investigates how copper mining influences the dispersion of these elements in the wind-transportable fraction (<75 mu m) of surface sediments across an 80 km radius. We employed a multi-pronged approach, utilizing spatial modeling to map element distributions, exponential decay analysis to quantify concentration decline with distance, regime shift modeling to identify dispersion pattern variations, and pollution assessment to evaluate impact. Our results reveal significant mining-driven increases in surface concentrations of copper (Cu), molybdenum (Mo), and arsenic (As). Notably, within the first 20 km, concentrations peaked at 1,016 mg kg(-1) for Cu, 31 mg kg(-1) for Mo, and a remarkable 165 mg kg(-1) for As. Cu and Mo displayed significant dispersion, extending up to 50 km from the source. However, As exhibited the most extensive reach, traveling up to 70 km downwind, highlighting the far-reaching ecological footprint of mining operations. Mineralogical analyses corroborated these findings, identifying mining-related minerals in surface sediments far beyond the immediate mining area. Although pollution indices based on the proposed Local Geochemical Background reveal significant contamination across the study area, establishing accurate pre-industrial baseline values is essential for a more reliable assessment. This study challenges the concept of "natural pollution" by demonstrating that human activities exacerbate baseline metal(loid)s levels. Expanding monitoring protocols is imperative to comprehensively assess the combined effects of multiple emission sources, including mining and natural processes, in safeguarding environmental and human health for future generations.
Metals and metaloid preserved in marine sediments of an industrial complex of central Chile. Environmental assessment using different background values
(ELSEVIER, 2024) Valdés Saavedra, Jorge; Quiroga, Eduardo
This work examines the distribution of metals(oid) in coastal sediments of the Concon-Quintero industrial complexes (central Chile), and evaluates the environmental condition of this zone, using some environmental indexes and different global and local background values. The Index of geoaccumulation and the Enrichment Factor were different depending on the background values used to calculate them. Only Mo and Pb, simultaneously show both an enrichment, and some degree of pollution problem, with all backgrounds utilized. Three of the four background values used in this work to calculates the Pollution Load Index suggests a polluted condition of the bottom environment. The spatial distribution, the results of environmental indices and the comparison with local environmental legislation suggests that Pb is introduced to the marine system by industrial activities. The result of both, SQG and m-ERM-Q suggest that metals preserved in the sediments are a threat to the benthic life, especially in the Concon-Ritoque zone, where the highest values were recorded. These results suggest a notorious influence of the Aconcagua river on the metal accumulation in the coastal zone.
Differences in the adulteration degree and antimicrobial activity of chilean ulmo honey versus multifloral honey revealed by stable isotope analysis
(ELSEVIER, 2024) Pérez, Pablo; Lavín, Paris; Harrod, Chris; Echeveste, Pedro
Honey, valued for its nutritional and antimicrobial benefits, has experienced an increased production in recent decades. However, this rise has been accompanied by concerns of adulteration, often involving the fraudulent addition of sugars. Our study sought to compare the physicochemical and isotopic properties of various honeys available to Chilean consumers, assessing the extent of adulteration. Samples included honey produced from bees that fed on multiple flowers and those fed by ulmo flowers – an endemic species of South America that produces a high-quality, high-cost honey – and analyzed for antimicrobial activity against Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. The analysis of ash content (%), moisture (%), pH and total phenolic content (mg GAE/100 g honey) found little obvious differences among honeys regardless of the feeding flowers (multifloral vs ulmo), type of purchase market (formal vs informal) or origin of the honeys (Central vs Southern Chile). However, the use of stable isotope analysis (δ 13 C and δ 15 N) of honey provided a powerful means to identify the degree of adulteration prior to the point of sale. Multifloral honeys purchased at informal markets were all adulterated, and ulmo honeys included both the least and most adulterated honeys. Regarding their antimicrobial activity, most multifloral honeys were less effective than ulmo honeys. Notably, while multifloral honey activity was independent of adulteration, the antimicrobial activity of ulmo honey was negatively affected by adulteration.
Why aquatic scientists should use sulfur stable isotope ratios (ẟ34S) more often
(ELSEVIER, 2024) Raoult, Vincent; Phillips, Alexandra A.; Nelson, James; Niella, Yuri; Skinner, Christina; Bell Tilcock, Miranda; Burke, Patrick J.; Szpak, Paul; James, W. Ryan; Harrod, Chris
Over the last few decades, measurements of light stable isotope ratios have been increasingly used to answer questions across physiology, biology, ecology, and archaeology. The vast majority analyse carbon (δ13C) and nitrogen (δ15N) stable isotopes as the ‘default’ isotopes, omitting sulfur (δ34S) due to time, cost, or perceived lack of benefits and instrumentation capabilities. Using just carbon and nitrogen isotopic ratios can produce results that are inconclusive, uncertain, or in the worst cases, even misleading, especially for scientists that are new to the use and interpretation of stable isotope data. Using sulfur isotope values more regularly has the potential to mitigate these issues, especially given recent advancements that have lowered measurement barriers. Here we provide a review documenting case studies with real-world data, re-analysing different biological topics (i.e. niche, physiology, diet, movement and bioarchaeology) with and without sulfur isotopes to highlight the various strengths of this stable isotope for various applications. We also include a preliminary meta-analysis of the trophic discrimination factor (TDF) for sulfur isotopes, which suggest small (mean 0.4 ± 1.7 ‰ SD) but taxa- dependent mean trophic discrimination. Each case study demonstrates how the exclusion of sulfur comes at the detriment of the results, often leading to very different outputs, or missing valuable discoveries entirely. Given that studies relying on carbon and nitrogen stable isotopes currently underpin most of our understanding of various ecological processes, this has concerning implications. Collectively, these examples strongly suggest that researchers planning to use carbon and nitrogen stable isotopes for their research should incorporate sulfur where possible, and that the new ‘default’ isotope systems for aquatic science should now be carbon, nitrogen, and sulfur.
Diet of Andean Leaf-Eared Mice (Phyllotis) Living atExtreme Elevations on Atacama Volcanoes: Insights FromMetagenomics, DNA Metabarcoding, and Stable Isotopes
(WILEY, 2024) Quezada Romegialli, Claudio; Quiroga Carmona, Marcial; D'Elía, Guillermo; Harrod, Chris ; Storz, Jay F.
On the flanks of > 6000 m Andean volcanoes that tower over the Atacama Desert, leaf-eared mice (Phyllotis vaccarum) live at extreme elevations that surpass known vegetation limits. The diet of these mice in these barren, hyperarid environments has been the subject of much speculation. According to the arthropod fallout hypothesis, sustenance is provided by windblown in-sects that accumulate in snowdrifts (“aolian deposits”). Mice may also feed on saxicolous lichen or forms of cryptic vegetation that have yet to be discovered at such high elevations. We tested hypotheses about the diet of mice living at extreme elevations on Atacama volcanoes by combining metagenomic and DNA metabarcoding analyses of gut contents with stable isotope analyses of mouse tissues. Genomic analyses of contents of the gastrointestinal tract of a live-captured mouse from the summit of VolcánLlullaillaco (6739 m) revealed an opportunistic but purely herbivorous diet, including lichens. Although we found no evidence of animal DNA in gut contents of the summit mouse, stable isotope data indicate that mice from elevations at or near vegetation limits (~5100 m) include a larger fraction of animal prey in their diet than mice from lower elevations. Some plant species detected in the gut contents of the summit mouse are known to exist at lower elevations at the base of the volcano and in the surrounding Altiplano, suggesting that they may occur at higher elevations beneath the snowpack or in other cryptic microhabitats.
New northernmost distribution records of the Eastern South Pacific southern right whale (Eubalaena australis), including the first cases from Ecuador and northern Peru
(Public Library of Science, 2024) Castro Ayala, Cristina; García-Cegarra, Ana M.; Uceda-Vega, Piero; Aguilar, Luis; Kelez, Shaleyla; Buchan, Susannah J.; Félix, Fernando; Stack, Stephanie H.; Van Waerebeek, Koen
The Eastern South Pacific Right Whale (SRW) (Eubalaena australis) population has gained interest due to its Critically Endangered conservation status. So far, this population has been confirmed only along the coasts of Chile (18˚20’S to 56˚30’S) and from southern to central Peru (17˚38’S to 12˚11’S). Recent records have extended the species’ known range, highlighting its geographic distribution, now reaching 1500 km north. Here, we report six recent records, consisting of five sightings and one stranding, that expand the documented range to northern Ecuador (0.6˚N). The northern extension of the population may be associated with the unusual three-year-long cold phase (La Niña) of the El Niño Southern Oscillation (ENSO) in the eastern South Pacific, population expansion, movement and redistribution of the species, increased monitoring effort, or a combination of these factors. These observations raise hope for the Critically Endangered SRW population, as the occurrence of mother-calf pairs may indicate a potential for population recovery. Nevertheless, these findings intensify concerns for what is still the least abundant SRW population, underscoring the urgency for more targeted research and conservation measures.
Isolation of Thermophilic Bacteria from Extreme Environments in Northern Chile
(MDPI, 2024) Valenzuela, Bernardita; Solís-Cornejo, Francisco; Araya, Rubén; Zamorano, Pedro
The northern region of Chile boasts unique geographical features that support the emergence of geothermal effluents, salt lagoons, and coastal creeks. These extreme climate conditions create polyextreme habitats for microorganisms, particularly adapted to survive these harsh environments. These extremophilic microorganisms hold immense potential as a source of hydrolytic enzymes, among other biotechnological applications. In this study, we isolated 15 strains of aerobic thermophilic bacteria (45–70 ◦C) from sediment samples collected at five different ecological sites, including hot springs, geothermal fields, and lagoons in the Atacama Desert and Andes high planes. Analyses of the 16S rRNA gene sequences of the isolates showed a close genetic similarity (98–100%) with microorganisms of the genera Parageobacillus, Geobacillus, Anoxybacillus, and Aeribacillus. Notably, these thermophiles exhibited significant hydrolytic enzyme activity, particularly amylases, lipases, and proteases. These findings underscore the potential of using these thermophilic bacterial strains as an invaluable source of thermozymes with wide-ranging applications in diverse industries, such as detergent formulations, pharmaceutical processing, and food technology. This research highlights the ecological significance of these extreme environments in the Atacama Desert and Andes high plains, which serve as vital ecological niches housing extremophilic bacteria as a genetic source of relevant thermozymes, promising great potential for innovation in the biotechnology industry.
Progress towards development of a unique pearl culture technology for red abalone (Haliotis rufescens) in Chile
(ELSEVIER, 2024-02-01) Sáez-Saavedra, Camila; Saucedo, Pedro E.; Acosta-Salmon, Hector; Tanguy, Arnaud; Araya, Rubén
Abalone pearl farming is an aquaculture activity with great potential for future growth and diversification of the global pearl sector, which has been dominated for decades by pearls of marine pearl oysters of the genus Pinctada. Despite this potential, there is a significant lack of knowledge regarding methods for nucleus (bead) seeding and the process of pearl formation in abalone, compared to the well-studied pearl oyster model. To address this problem, this review first compares the main anatomical differences and similarities between both groups of mollusks, particularly those associated with the structure and role of mantle tissue on the synthesis of CaCO 3 compounds that integrate the inner nacreous layer. The iridescence (orient) and color properties of nacre in a cultured pearl is particularly related to the microstructure of aragonite crystals during biomineralization in each mollusk group. We then analyze the advantages and disadvantages of the adoption in abalone of methods originally developed for pearl oysters to produce bead-seeded pearls and half-pearls (or mab´e pearls). For the red abalone Haliotis rufescens in particular, updated information on commercial production of both bead-seeded and mab´ e pearls is provided as a case of success for Latin America (Chile). Finally, the current status and future prospects for abalone pearl farming are discussed, assessing technology gaps and challenges to be addressed for the pearl sector to achieve its full potential, particularly for Latin America.
The Diversity of Metazoan Parasites of South American Stromateidae (Pisces: Teleostei) Is Related to Marine Biogeography
(MDPI, 2024-02-01) Oliva, Marcelo E.; Ñacari, Luis A.; Escribano, Ruben; Luque, José L.
The diversity of parasite communities is mainly driven by evolutionary history, as well as the ecology of the host species. To test whether the diversity of the parasite community of four related Stromateidae (Pisces: Scombriformes) is related to evolutionary history (the host phylogeny) or the host’s geographical distribution, we analyzed the metazoan parasite fauna of four species of fishes of this family, from the Pacific and Atlantic coasts of South America. Studied species were Peprilus snyderi (samples from Callao, Perú, and Antofagasta, Chile), Peprilus medius (Chorrillos, Perú), Peprilus paru (Rio de Janeiro, Brazil) and Stromateus stellatus (Talcahuano, Chile). Our multivariate analysis strongly suggests that the diversity of the parasite fauna of the studied fishes is driven mainly by the host’s geographical distribution and not the host phylogeny.
Tolerance of free-living larval stage of a parasite from coastal mining areas in northern Humboldt Current to copper pollution at low and high temperatures
(Public Library of Science, 2024-11-01) Leiva, Natalia V.; Montenegro, Diana; Orrego, Rodrigo; Vidal, Rodrigo; González, M.Teresa.
Metal pollution is a worldwide problem and one of the greatest threats to ecosystem integrity due to its toxicity, persistence, and bioaccumulation in biological systems. Anthropogenic pollution impacts marine organisms and host-parasite dynamics, with the northern Chilean coast experiencing elevated copper levels in marine waters and sediments due to mining activities. In this study, we assessed the effects of exposure to copper concentrations at low and high-water temperatures on the survival and longevity of the marine parasite Himasthla sp. cercariae (Trematoda: Digenea) using the snail Echinolittorina peruviana as its first intermediate host. Snails were collected from intertidal rocky pools in northern Chile (23 degrees S). To assess parasite survival and longevity, cercariae were collected from a pool of infected snails, and their mortality was recorded every 6 hours until all cercariae were dead. In a preliminary experiment conducted at 19 degrees C, cercariae were exposed to different copper concentrations (0.2, 1.5, 3.0, and 6.0 mg/L) for 78 hours. Cercariae showed tolerance to copper. However, at the higher copper concentration (6 mg/L), survival was negatively impacted (50%) at 54 hours. In contrast, at the lower concentration (0.2 mg/L) and in the control group, cercariae sustained a 73-90% survival rate even after 54 hours. Based on these findings, we conducted subsequent experiments involving two copper treatments (0.2 and 3.0 mg/L) and two temperatures (14 and 22 degrees C). Survival and longevity were significantly higher at lower temperature and copper concentration (14 degrees C and 0.2 mg/L). Conversely, at higher temperature and copper concentration (22 degrees C and 3 mg/L), survival and longevity decreased to only 66 hours. Our results show that Himasthla sp. cercariae tolerated most copper concentrations, with vulnerability observed primarily in high water temperatures, indicating an adverse effect on cercariae performance. This study contributes valuable insights into how parasites respond to environmental pollution, in marine ecosystems influenced by anthropogenic activities.
Heavy metals and trace elements in a threatened population of guanay cormorants (Leucocarbo bougainvilliorum) from an industrialized bay in the Humboldt Current System, Chile
(Elsevier GmbH, 2025) Carretero, Jorge; Garcia-Cegarra, Ana M; Martinez-Lopez, Emma
Metal contamination from industrial and mining activities threatens coastal and marine ecosystems, leading to bioaccumulation in marine organisms and biomagnification through the trophic chain. The Guanay cormorant (Leucocarbo bougainvilliorum), an endemic species of the Humboldt Current System, is experiencing population declines and serves as a key bioindicator of heavy metal contamination due to its high trophic position, reliance on commercially exploited pelagic fish, and capacity to accumulate contaminants over time. This study analyzed the concentrations of five heavy metals (Hg, As, Pb, Cr, Cd) and three trace elements (Cu, Zn, Se) in liver, muscle, feathers, and kidney of 10 Guanay cormorants found dead in Mejillones Bay, Chile, a highly industrialized area. Feathers exhibited the highest concentrations of Cr (2.03 ± 0.63 mg/kg), Cu (19.72 ± 3.82 mg/kg), and Zn (109.84 ± 11.95 mg/kg), emphasizing their role in detoxification. Females showed significantly higher Cu and Pb concentrations in muscle and Cr in kidneys, likely due to physiological and hormonal differences related to reproduction. Correlations between metal concentrations across tissues suggest shared bioaccumulation mechanisms, while the Hg:Se molar ratio (e.g., 0.25 ± 0.04 in liver) indicated a protective role of Se against Hg toxicity. Metal concentrations were comparable to those reported in other marine cormorants but differed from freshwater populations, highlighting the influence of habitat on metal accumulation. Although current levels do not indicate acute toxicity, the ongoing population decline of Guanay cormorants underscores the need for long- term biomonitoring. Future research incorporating biochemical and enzymatic biomarkers is essential to assess potential sublethal effects and long-term ecological risks associated with heavy metal exposure in this species.
Unveiling a new species of Trapania (Gastropoda: Nudibranchia: Goniodorididae) from the South-eastern Pacific using anatomical and molecular tools
(Cambridge University Press, 2025) Uribe, Roberto A; Mendivil, Alejandro; Pastor, Ruslan; Atoche-Suclupe, Dennis; Aleman, Solange; Flores, Lorenzo; Sepulveda, Fabiola
Morphological and molecular methods were used to describe a new species ofTrapaniaPruvot-Fol, 1931 from shallow water kelp forests on the north-central coast of Peru. Thenew species,Trapania huarmeyana sp. nov., is distinguished from other species along theEastern Pacific by external morphological characters such as its translucent white bodywith brown stripes and small spots on the dorsum, blotches on the base of the extra-branchialprocesses, extra rhinophoral processes and gill branches. Internally,T. huarmeyanasp. nov. isdistinguishable by several morphological characteristics of the radula, jaws and genital organs.Phylogenetic trees recovered using Bayesian Inference and Maximum Likelihood analysis ofDNA sequences support its distinct status and clarify its relationship to other species fromthe Eastern Pacific. This new species constitutes the first record ofTrapaniafrom theHumboldt Current Ecosystem, contributing to our understanding of the distribution of thegenus in the South-eastern Pacific.
New record of Frilled shark Chlamydoselachus anguineus Garman, 1884 (Chondrichthyes: Hexanchiformes) in the South Pacific Ocean
(PeerJ Inc., 2025) Indurain, Maria J; Mancilla, Angel; Brizuela, Leandro; Vargas-Caro, Carolina; Bustamante, Carlos
Frilled sharks are rarely observed and limited information is available regarding their life history. The global number of records for these sharks does not exceed 40, with most sightings reported in the Western Pacific Ocean. In 1976, one specimen was recorded for the first time in the South East Pacific Ocean; however, this study provides new evidence for the presence of Chlamydoselachus anguineus in Chilean waters, extending its distribution range 850 km south of the previous record. The morphological features of all specimens from Chile are discussed, supplementing previous observations and adding to the existing knowledge on this species in the Pacific Ocean.
Integrating Egg Case Morphology and DNA Barcoding to Discriminate South American Catsharks, Schroederichthys bivius and S. chilensis (Carcharhiniformes: Atelomycteridae)
(MDPI, 2025) Bustamante, Carlos; Vargas-Caro, Carolina; Indurain, Maria J; Silva, Gabriela
Catsharks are benthic elasmobranchs that share spatial niches with littoral and demersal bony fishes. The genus Schroederichthys includes five species, two of which, S. chilensis and S. bivius, occur in the waters of Chile. These species are morphologically similar and are often misidentified because of their overlapping external features and color patterns. To improve species discrimination, we analyzed the egg case morphology of both species based on 36 egg cases (12 S. chilensis, 24 S. bivius) collected from gravid females captured as bycatch in artisanal fisheries between Iquique and Puerto Montt (July–December 2021). Nine morphometric variables were measured and standardized using the total egg case length. Although the egg cases were similar in general appearance, multivariate analyses revealed significant interspecific differences, with egg case height and anterior border width emerging as the most diagnostic variables. Linear discriminant analysis achieved a 100% classification accuracy within this dataset. To confirm species identity, 24 tissue samples (12 per species) were sequenced for the mitochondrial cytochrome c oxidase subunit I (COI) gene. The haplotypes corresponded to previously published sequences from Chile (S. chilensis) and Argentina (S. bivius), with reciprocal monophyly and 100% bootstrap support. While COI barcoding provided robust confirmation, the core contribution of this study lies in the identification of species-specific egg case morphometrics. Together, these findings establish a dual-track toolkit, egg case morphology for primary discrimination and COI barcodes for confirmatory validation, that can be incorporated into bycatch monitoring and biodiversity assessments, supporting the conservation of poorly known catsharks in the Southeast Pacific.
Origin, trophic transfer and recycling of particulate organic matter in two upwelling bays of Humboldt Current System: Insights from compound-specific isotopic compositions of amino acids
(Public Library of Science (PLOS), 2025) Srain, Benjamin; Flores, Edgart; Valdes, Jorge; Camano, Andres
The Chilean upwelling bays are highly productive ecosystems shaped by their inter-actions with the open ocean. Although significant knowledge exists regarding their hydrodynamic and ecological processes, the spatial dynamics of trophic transfer and heterotrophic resynthesis of organic matter remain insufficiently understood. To address these knowledge gaps, we conducted a compound-specific isotope analysis of amino acids (CSIAA) on suspended and sinking particulate organic matter from Mejillones and Antofagasta bays, two oceanographic environments characterized by contrasting hydrodynamic conditions and topographic orientations. In Mejillones Bay, the CSIAA trophic positions for metazoan (1.7 ± 0.5) and protozoan (2.3 ± 0.3) were significantly higher compared to those in Antofagasta Bay (metazoans: 1.3 ± 0.6; protozoans: 1.5 ± 0.3), highlighting protozoans as primary trophic vectors. MixSIAR analysis indicated that phytoplankton is a key source of particulate organic matter in both bays; however, Mejillones Bay exhibited a greater proportion of microbially degraded organic matter. Enhanced heterotrophic resynthesis in Mejillones Bay (ΣV: 1.9–2.5) was associated with lower oxygen levels, increased concentrations of NO₂⁻ , and heightened stratification of the water column. Additionally, depth-dependent variations in δ15N for phenylalanine and threonine indicated a greater solubilization of particles, which contributed to a reduction in the export of particulate organic matter (averaging 9 ± 2 mg C/m²/d). These findings underscore the critical role of the intricate interactions between the bay’s topographic features and the physical and biological processes that ultimately influence the cycling trajectories of particulate organic mat-ter in upwelling bays
Metazoan Parasite Communities of Two Sympatric Shortnose Chimeras (Holocephali: Chimaeridae) from Deep Waters Associated with the Humboldt Current System: Ancient Fishes Harbor Ancient Parasites
(MDPI, 2025) Oliva, Marcelo E; Nacari, Luis A; Espinola-Novelo, Juan F
A total of 61 specimens of deep-sea chimaeras (Hydrolagus melanophasma = 41; Chimaera sp. = 20) were obtained during September 2017 as by-catch of the local fishery of the Patagonian toothfish (Dissostichus eleginoides, Pisces: Nototheniidae) along the northern Chilean coasts (≈22°20′ S) at depths ranging from 950 to 1500 m using a deep-sea longline. Nine species of metazoan parasites were found in H. melanophasma and seven in Chimaera sp. Four species were shared between both host species. Gyrocotyle sp.1 (Cestodaria) and Multicalyx elegans (Aspidogastrea) showed the higher prevalence H. melanophasma (68.3% and 65.38%, respectively), whereas Plectognathotrema hydrolagi (Digenea), Gyrocotyle sp.1 (Cestodaria), and Chimaericola sp. (Monogenea) showed higher prevalence in Chimaera sp. (90%, 55% and 55%, respectively). Beta diversity analysis reveals that the parasite communities of these two related and sympatric species are strongly differentiated. Our results suggest a strong relationship between the ancient Holocephali, which harbor ancient parasites belonging to Rugogasteridae and Multicalycidae (Aspidogastrea), and two Cestodaria species. Chimaera spp. are also parasitized by some highly specific monogeneans, such as Chimaericola spp. Our results demonstrate the differences in the parasite community structures—both of ecto- and endoparasites—of two related and sympatric hosts.
Pingers as a potential deterrent tool to mitigate Burmeister's porpoise (Phocoena spinipinnis) bycatch while foraging nocturnally in the Humboldt Current System: a pilot study
(Frontiers Media SA, 2025) Diaz, Diego; Garcia-Cegarra, Ana M
Fisheries bycatch is one of the main threats for porpoise species worldwide. In the Humboldt Current system of northern Chile, the elusive Burmeister’s porpoise (Phocoena spinipinnis) inhabits the coastal waters of Mejillones Bay and suffers bycatch mortality in purse seine fishing nets and coastal gillnets. In order to mitigate bycatch of this near-threatened species, this study aimed to (1) analyze the diurnal and nocturnal acoustic behaviors of the Burmeister’s porpoise and (2) evaluate the potential of banana pingers as acoustic deterrent tools. For 27 days during austral summer, a full wave form capture porpoise detector was anchored 7 m above sea level in Mejillones Bay where Burmeister’s porpoises are frequently observed. During this time, the detector registered acoustic activity continuously over 13 days, and a banana pinger deployed over 100 m away from the detector emitted high frequency sounds continuously for 14 days. The results show that the number of clicks and detection-positive minutes were significantly higher while the inter-click intervals and high click rate feeding buzz were significantly lower at night, indicating that Burmeister’s porpoises forage mainly nocturnally in this bay. With pingers present, the probability of detection of Burmeister’s porpoise acoustic activity decreased by 20%, suggesting that pingers could be an effective tool to avoid Burmeister’s porpoise mortality in fishing nets. Future studies should implement pingers in artisanal purse seine fishing nets and coastal gillnets in order to mitigate Burmeister’s porpoise bycatch in northern Chile.
Biogeographic Insights Into the Late Miocene Diversification of the Giant Deep-Ocean Amphipod Eurythenes
(Wiley, 2025) Gonzalez, Carolina E; Weston, Johanna N. J; Rivera, Reinaldo; Oliva, Marcelo; Escribano, Ruben; Ulloa, Osvaldo
Mechanisms driving the spatial and temporal patterns of species distribution in the Earth's largest habitat, the deep ocean, remainlargely enigmatic. The late Miocene to the Pliocene (~23–2.58 Ma) is a period that was marked by significant geological, climatic,and oceanographic changes. This transitional period spurred widespread species diversification, particularly among widely dis-tributed benthic scavengers, such as amphipods. Here, we take step toward understanding the long-term evolutionary processesof amphipod colonization and diversification in the deep ocean by focusing on the model genus Eurythenes S. I. Smith in Scudder,1882. These large-bodied scavengers play key roles in benthic communities. We constructed a time-calibrated phylogeny usingtwo mitochondrial DNA genes by analyzing publicly available data on 14 species of Eurythenes across a global depth range from839 to 8081 m. The resulting phylogenetic tree reveals a diverse clade, with a common ancestor originating around 11.81 Ma. Agradual increase in the effective population size of Eurythenes was observed, particularly during the Pliocene (~4 Ma). The netdiversification rate remained almost constant, with slight increases between the Miocene and Pliocene (~8–4 Ma), and most newspecies appeared during the latter period. Additionally, reconstruction of the ancestral area suggested that the common ancestorof Eurythenes had a global distribution. A combination of dispersal and sympatric processes, along with environmental factors,such as changes in ocean temperature and sea level, contributed to the present biogeographic distribution of these species. Ourfindings highlight the importance of historical events, such as plate tectonics and changes in deep-water circulation, in drivingthe rapid speciation of Eurythenes and underscore their essential role in shaping deep-ocean biodiversity
Impact of multiple-factors on health and infections in marine mussels (Perumytilus purpuratus) inhabiting contaminated sites in the Humboldt Current System
(Nature Portfolio, 2025) Montenegro, Diana; Gonzalez, Maria Teresa
Marine organisms are increasingly exposed to a combination of environmental stressors. However, most studies focus on single factors, limiting our understanding of real-world ecological challenges. This study investigates the combined effects of metal pollution, parasites, pathogens, and environmental variables on the health of Perumytilus purpuratus, a mussel species inhabiting the coast of northern Chile. The upwelling system in this area, combined with low water turnover, creates a unique environment in which to study how multiple factors interact. Mussels were sampled from several sites affected by metal discharges. Analyses revealed that individuals from central and northern sites exhibited the highest levels of parasites, pathogens, and tissue lesions. These health impacts were strongly associated with elevated pH, salinity, cadmium and copper concentrations in the water. Findings emphasise the synergistic effects of chemical and abiotic factors, underscoring the importance of incorporating multiple factors interactions into monitoring programmes. Such an approach can enhance predictions of ecological responses, inform conservation efforts, and guide policies addressing global challenges like aquatic pollution. Our study provides critical insights into how combined factors threaten aquatic ecosystems, offering a framework for more comprehensive environmental assessment.
Physiological capacity of Pinctada mazatlanica to receive xenografts from Pteria sterna, as a criterion to improve pearl production and quality
(Elsevier, 2025) Trejo-Rodriguez, Karla; Granados-Amores, Andres; Arellano-Martinez, Marcial; Acosta-Salmon, Hector; Campa-Cordova, Angel I; Rojas-Figueroa, Alejandro; Saucedo, Pedro E
This study reports the survival, hemocyte count and physiological response indicators of pearl oysters Pteria sterna and Pinctada mazatlanica seeded with allografts and xenografts for pearl culture. Two treatments of oysters receiving an allograft (both donor and host were Pt. sterna) or a xenograft (donor was Pt. sterna and host was P. mazatlanica) were compared against two control groups of unseeded oysters (allografts and xenografts) at 0, 0.5, 2, 24, and 72 h. While survival was not affected by any particular treatment, the number of circulating hemocytes was inversely proportional in both species; it did not vary in Pt. sterna after allografting from t0 to 2 h, but then gradually increased and reached a 4-fold peak at 72 h that differed significantly from its control group and t0. In P. mazatlanica, the hemocyte count increased significantly (3-fold) at 0.5 h after xenografting, but then gradually decreased to equal the value of its control group and t0 at 72 h. In Pt. sterna, glycogen and mucopolysaccharide indices decreased >50 % at 2 h and gradually returned to the initial value at 72 h. In contrast, neither index varied significantly in P. mazatlanica, indicating almost no use of energy stores to compensate for the effects of xenografting, as well as little mucus production due to tissue irritation, compared to allografting in Pt. sterna. The lipofuscin index followed a relatively stable pattern over time in treatments A and X and changes with respect to their control groups CA and CX were not significant up to 72 h. Our results indicate that P. mazatlanica responded significantly faster to xenografting and wound healing than Pt. sterna to allografting, and may be a viable host to receive Pt. sterna xenografts. This could contribute to improve pearl yield and quality in Pt. sterna.

Examinar

Examinando Instituto de Ciencias Naturales Alexander von Humboldt por Fecha de publicación

Resultados por página

Opciones de ordenación