The study focused on the life cycle of Chondracanthus chamissoi, characterized by its isomorphic triphasic phase and spore propagation. The effect of phytohormones in alternative culture media on the settlement and growth of gametophytes was evaluated. Tetraspores were inoculated on polypropylene ropes and exposed to six treatments with different concentrations of a hormonal solution (gibberellins, auxins, cytokinins). Over 10 weeks, the number of settled spores, disc density, and microthallus size were measured. The results showed increased growth with higher concentrations of phytohormones, the treatment with 100% phytohormones (T1) produced the highest amount of developed discs (133 ± 9 mm-2), which confirms its positive effect on the morphogenesis of C. chamissoi, while the treatment without phytohormones (T6) showed the lowest amount of developed discs (25 ± 10 mm-2) suggesting their usefulness in the propagation of this economically important species.
Anomalies in skin or plumage pigmentation have been recorded across various vertebrate species, albeit infrequently. Factors such as pollution and genetics are indicated as the causes. This study reports for the first time, a case of color aberration (albinism or Brown) in a juvenile Humboldt penguin Spheniscus humboldti individual on the Hualpén Peninsula, Chile, along with an update of the literature comprising 25 reported cases of these anomalies in the Chilean wildlife.
The reproductive biology of female Helcogrammoides cunninghami was analyzed using histological sections of the ovary to describe the stages of oocyte development. The spawning season was determined based on the frequencies of each maturity stage, the gonadosomatic index (GSI), the gonadal index (GI), and the condition factor (K). The size at first maturity was estimated by considering the relative increase in GSI as a function of size, while partial fecundity was calculated using the gravimetric approach. According to these analyses, the main spawning period occurs during the austral autumn, followed by a secondary, less intense period in the austral spring. The size at maturity was estimated at 48 mm total length (TL), and partial fecundity ranged from 230 to 570 oocytes per female, depending on TL and total weight (TW). These results indicate that H. cunninghami is an asynchronous ovulator and a partial spawner, with a bimodal reproductive cycle featuring peaks in the austral autumn and spring.
This review presents the production and use of biochar in terms of chemical structure, utilization, and current global market, with an emphasis on the biotechnological applications of seaweed biochar. For this purpose, a literature search was conducted in various databases, using keywords and algorithms in both Spanish and English. The results indicate that biochar from seaweed is an efficient alternative for the remediation of terrestrial and/or aquatic ecosystems. The capacity to capture different types of pollutants (microplastics, heavy metals, polycyclic aromatic hydrocarbons, among others) provides biochar properties that make it an appropriate material for environmental remediation, including the reduction of greenhouse gas emissions. The co-production of biochar and bioenergy is an alternative to mitigating the effects of climate change, contributing to reduce the use of fossil fuels and sequestering carbon in stable soil reserves. In addition, the use of biochar as a soil amendment and fertilizer is a significant tool for increasing food security and expanding crop areas in zones with physically and chemically degraded soils, characterized by low organic matter content, inadequate chemical fertilizer content, poor water retention and toxicity from pollutants. Therefore, the use of seaweed biochar is an environmental tool with high added value.
Zooplankton biomass is an indirect proxy of secondary production and a measure that allows estimates to be made about the availability of matter in the food web. This study compares the wet biomass of zooplankton within the Bay of La Paz, the largest and deepest coastal water body in the Gulf of California, Mexico. It analyzes the influence of the physical forcing in zooplankton biomass and distribution. Two research cruises were conducted in February 2006 and August 2009, recording high-resolution hydrographic data and collecting zooplankton. The hydrographic properties of the seawater column changed in both seasons. The circulation pattern was dominated by a well-defined cyclonic eddy with different azimuthal velocities, being more intense in summer (75 cm s(-1)) than in winter (20 cm s(-1)). Zooplankton biomass showed slightly lower values in winter (43.4 g 100 m(-1)) than in summer (45.5 g 100 m(-1)). Its horizontal distribution showed that the highest values were observed in the shallow stations, close to the coast, and in the connection with the Gulf of California. However, high secondary values were observed at the eddy's peripheries, describing a circular distribution pattern following their circumference, which could be attributed to 1) eddies retain zooplankton organisms and advect them to their periphery, and 2) mixing processes at the eddies peripheries ensure food (phytoplankton) for zooplankton organisms.
Coral reefs are ecosystems with high biological diversity that, under anthropogenic and climatic stress, produce chemical defense compounds. Different indicators have been used to measure the health of coral systems. The concentration of total phenols could be used for this purpose due to their antioxidant response during harsh environmental conditions, although this stress indicator has received little attention. The total content of phenols, chlorophyll-a, chlorophyll c(1 )+ c(2), and beta-carotenes was evaluated in Pocillopora capitata corals collected at three sites of the Central Mexican Pacific under multiple stress conditions in two different seasons of the year. Total phenol content, chlorophyll-a, chlorophyll c(1 )+ c(2), and beta-carotene concentrations ranged from 1.49 to 4.43 mu g GAE mL(-1), 1.28 to 2.08 mu g cm(-2), 0.15 to 0.43 mu g cm(-2), and 0.20 to 0.77 mu g cm(-2), respectively. The content of total phenols and beta-carotenes between seasons had statistically significant differences, where the total content of phenols and pigments tended to be higher in the rainy season (October) than in the dry season (February), as these compounds are sensitive to environmental fluctuations and may therefore serve as indicators of such changes.
The study focused on the life cycle of Chondracanthus chamissoi, characterized by its isomorphic triphasic phase and spore propagation. The effect of phytohormones in alternative culture media on the settlement and growth of gametophytes was evaluated. Tetraspores were inoculated on polypropylene ropes and exposed to six treatments with different concentrations of a hormonal solution (gibberellins, auxins, cytokinins). Over 10 weeks, the number of settled spores, disc density, and microthallus size were measured. The results showed increased growth with higher concentrations of phytohormones, the treatment with 100% phytohormones (T1) produced the highest amount of developed discs (133 +/- 9 mm-2), which confirms its positive effect on the morphogenesis of C. chamissoi, while the treatment without phytohormones (T6) showed the lowest amount of developed discs 25 +/- 10 mm-2 suggesting their usefulness in the propagation of this economically important species.
The main food sources in sandy beaches are stranded animals and seaweeds. In species with low dispersal potential or reduced mobility, it is expected that local adaptations or plastic responses arise to confront these environments and maximize fitness. Orchestoidea tuberculata is a common semi-terrestrial talitrid amphipod in Chilean sandy beaches and shows a very limited dispersal, with direct developmental mode and reduced mobility at the adult stage. O. tuberculata feeds on stranded seaweeds and organic material from animal origin during low tides. The effects of different diets on food preference, growth rate and survival of O. tuberculata individuals from two sandy beaches with different types of food availability were evaluated: Punta Hualp & eacute;n with high abundances of stranded seaweed and animals, and Lenga showing low levels of stranded seaweeds, and high levels of food of animal origin. To evaluate potential local responses in feeding behavior, individuals of O. tuberculata from both localities were fed with algae (Durvillaea incurvata) and animal carcasses (Emerita analoga) disposed in separate and mixed diets (D. incurvata + E. analoga). Results showed that food preference in O. tuberculata varies between individuals from the two sites. Individuals tended to show the highest performances with the diet composed of the most common dietary item available in their site of origin (algal or animal). These results may indicate the existence of potential local adaptations or feeding behavior plasticity in O. tuberculata as responses to the spatial variability of food availability observed in sandy beach ecosystems.
The reproductive biology of female Helcogrammoides cunninghami was analyzed using histological sections of the ovary to describe the stages of oocyte development. The spawning season was determined based on the frequencies of each maturity stage, the gonadosomatic index (GSI), the gonadal index (GI), and the condition factor (K). The size at first maturity was estimated by considering the relative increase in GSI as a function of size, while partial fecundity was calculated using the gravimetric approach. According to these analyses, the main spawning period occurs during the austral autumn, followed by a secondary, less intense period in the austral spring. The size at maturity was estimated at 48 mm total length (TL), and partial fecundity ranged from 230 to 570 oocytes per female, depending on TL and total weight (TW). These results indicate that H. cunninghami is an asynchronous ovulator and a partial spawner, with a bimodal reproductive cycle featuring peaks in the austral autumn and spring.
This review presents the production and use of biochar in terms of definition, chemical structure, utilization, and current global market, with an emphasis on the biotechnological applications of seaweed biochar. For this purpose, a literature search was conducted in various databases, using keywords and algorithms in both Spanish and English. The results indicate that biochar from seaweed is an efficient alternative for the remediation of terrestrial and/or aquatic ecosystems. The capacity to capture different types of pollutants (microplastics, heavy metals, polycyclic aromatic hydrocarbons, among others) provides biochar properties that make it an appropriate material for environmental remediation, including the reduction of greenhouse gas emissions. The co-production of biochar and bioenergy is an alternative to mitigating the effects of climate change, displacing the use of fossil fuels and sequestering carbon in stable soil reserves. In addition, the use of biochar as a soil amendment and fertilizer is a significant tool for increasing food security and expanding crop areas in zones with physically and chemically degraded soils, characterized by low organic matter content, inadequate chemical fertilizer content, poor water retention and toxicity from pollutants. Therefore, the use of seaweed biochar is an environmental tool with high added value.
Chondracanthus chamissoi es un alga roja cuyo valor comercial ha incrementado en los últimos años, al igual que su explotación. Debido a esto, es importante promover su cultivo como alternativa a la extracción de praderas naturales. Por ello es necesario contar con opciones que reduzcan los costos y faciliten el cultivo. Con respecto al suministro de nutrientes, las sales inorgánicas de grado analítico han sido comúnmente empleadas en el cultivo; sin embargo, se ha probado que algunos fertilizantes agrícolas pueden ser igualmente eficientes y resultan económicamente rentables para el cultivo de algas en laboratorio. La finalidad de este estudio fue evaluar el crecimiento de C. chamissoi con distintas concentraciones de un fertilizante agrícola (Bayfolan®) como fuente de nutrientes. Las concentraciones evaluadas fueron: 0,025; 0,05; 0,1; 0,2 y 0,4 mL L-1, más un control (agua de mar sin adición de nutrientes). Se obtuvieron diferencias significativas en la tasa de crecimiento de los microtalos, en donde el mayor crecimiento en la concentración fue de 0,2 mL L-1 con una tasa de crecimiento igual a 7,56% día-1; por el contrario, se obtuvo un crecimiento incipiente y alta mortalidad en el control y en la concentración de 0,4 mL L-1. Los resultados sugieren que Bayfolan® es una buena fuente de nutrientes en estadios tempranos de C. chamissoi; sin embargo, altas concentraciones pueden inhibir su crecimiento.
Se revela parte de la historia de vida del naturalista, profesor universitario e investigador en Ciencias del Mar, Jorge Nibaldo Bahamonde Navarro, Premio Nacional de Ciencias Naturales 1996. A través de la revisión documental y de conversaciones sostenidas con él, recuperamos la voz de uno de los formadores más queridos, reconocidos y respetados por sus exestudiantes -hoy pares en universidades nacionales-, investigadores extranjeros que trabajaron en Chile y la comunidad científica académica y no académica nacional e internacional. En el centenario del nacimiento de “don Nibaldo” -Jorge, su primer nombre, nunca lo utilizó-, quien proyecta una estatura moral y mantiene una figura de respeto y de cariño inalterables, le rendimos un homenaje de gratitud. En sus 100 años de historia es necesario rescatar biográficamente su personalidad y su entrega a la labor científica, académica y de divulgación; sin duda alguna, un aporte valioso para las futuras generaciones. Y, a través de él, aproximarnos a los naturalistas, quienes crearon, desarrollaron y promovieron las bases de la ciencia en Chile.
In coastal upwelling areas, the microphytoplankton community comprises two main groups, diatoms and dinoflagellates. However, neither group is uniform because physical-chemical and biological interactions can affect the community structure. In this work, the composition of the microphytoplankton community was analyzed at a fixed station located in Valparaíso Bay (~32°-33°S) using the Reynolds C-S-R model. In the bay, monthly variation of the microphytoplankton community occurred due to nutrient availability (nitrate-NO3-, silicate-SiO44-, and N/Si ratio), and water temperature, driven by upwelling activity. Three main communities were observed. The first one comprised neritic R diatoms such as Asterionellopsis glacialis, Chaetoceros radicans, and Chaetoceros tortissimus from late winter to early summer (August-December), when upwelling activity occurred with the ascent of cold and nutrient-rich water. In addition, dinoflagellates such as Protoperidinium brochii, Protoperidinium pellucidum, and Preperidinium meunieri were identified as part of this community. Secondly, S/R-S dinoflagellates such as Tripos furca var. berghii, Ceratium tripos f. tripodioides, Prorocentrum gracile, and Protoperidinium steinii were predominant under thermal stratification conditions from summer to autumn (January-April) together with C-R pennate diatoms such as Navicula sp. and Thalassionema nitzschioides. Finally, a community including neritic R-C/R diatoms such as Leptocylindrus danicus, Guinardia delicatula, Detonula pumila, Pseudo-nitzschia australis, Skeletonema costatum, Thalassiosira mendiolana, and Chaetoceros sp. was present throughout the year with no remarkable connection to any oceanographic conditions. Although upwelling activity constitutes the main driver of microphytoplankton community succession in the bay, biological interactions appear to play also a role, being necessary a deeper study under an ecological perspective. Key words: Microphytoplankton, community composition, diatoms, dinoflagellates, upwelling
Se presenta un análisis bibliométrico basado en los artículos científicos producidos por investigadores chilenos en los primeros 21 años del siglo XXI para trazar el desarrollo de la ciencia sobre mamíferos marinos, identificar las especies y temas de investigación más estudiados, así como los investigadores e instituciones chilenas involucradas. La búsqueda de información utilizó la base de datos ScopusTM, Web of Science (WoS) y Scientific Electronic Library Online (SciELO) para el período 2000-2021. Bibliometrix fue usado para obtener algunos índices de interés y VOSviewer para crear mapas de redes de co-ocurrencia. La distribución de las publicaciones mostró un crecimiento exponencial a una tasa anual del 10,8%, y 10 especies costeras (2 otáridos, 6 cetáceos y 1 mustélido) fueron los más estudiados. El análisis de palabras claves indicó que los estudios sobre distribución y alimentación fueron los tópicos más frecuentes, pero estudios de salud asociada a eventos de varamientos han surgido como áreas emergentes. También se da cuenta que pocos investigadores fueron responsables de una gran proporción de las contribuciones, siendo la Revista de Biología Marina y Oceanografía la editorial más frecuente de publicación. A nivel institucional, cuatro universidades, un centro de investigación regional y un servicio público serían los principales núcleos de producción de artículos de investigación sobre mamíferos marinos. Los conocimientos generados sugieren que el análisis bibliométrico es una herramienta útil para analizar tendencias en el avance científico de la mastozoología chilena.
Los equinodermos han sido reconocidos como una fuente rica de moléculas activas, con aplicaciones farmacológicas prometedoras en el campo de las investigaciones biomédicas. El objetivo del presente estudio fue evaluar la actividad biológica del extracto de naturaleza proteica de la estrella de mar Luidia magnifica mediante bioensayos citolíticos y citotóxicos. A partir de los brazos de la estrella de mar se obtuvo el extracto crudo, que demostró actividad antimicrobiana contra Escherichia coli y Candida albicans (CMI= 1,04 mg mL-1 y 0,52 mg mL-1, respectivamente), actividad hemolítica dosis dependiente (94,8% y EC50= 2,929 mg mL-1) sobre eritrocitos humanos, así como actividad citotóxica frente a la línea celular de glioma de rata C6, produciendo una inhibición celular de 52% y 32% de viabilidad celular, a una concentración de 20 mg mL-1 con los métodos de tinción rojo neutro y cristal violeta, respectivamente. Los resultados sugieren que la estrella de mar L. magnifica representa una fuente potencial de sustancias biológicamente activas que pudieran ser precursores de compuestos para el tratamiento de enfermedades.
Los pingüinos son uno de los grupos de aves marinas más amenazados en el planeta. La sistematización del conocimiento disponible es fundamental para la realización de un apropiado diagnóstico y estrategias de protección. El objetivo del presente trabajo fue realizar un diagnóstico sobre el estado del conocimiento de las dos especies de pingüinos (Spheniscus humboldti y Spheniscus magellanicus) que anidan en la Región de Los Lagos, sur de Chile, mediante una revisión bibliográfica e información inédita, identificando los sitios de nidificación y las prioridades de investigación para la conservación de estas aves marinas. Se recopilaron 31 estudios sobre pingüinos en la Región, publicados entre 1994 y 2022. La mayoría de los estudios se enfocaron en la determinación de presencia y estimación de abundancia de individuos (39%), seguido por estudios de genética y filogeografía (29%). Los islotes de Puñihuil son el sitio con mayor número de estudios (64%). Se identificó la existencia de al menos 18 sitios de nidificación de pingüinos en la Región, de los cuales sólo cuatro se ubican dentro de un área protegida. Finalmente, se identifican futuras preguntas de investigación y se sugiere crear una red de áreas protegidas que gestione de manera integral la conservación de pingüinos en la Región de Los Lagos.
A new species of Lepadomorpha barnacles (stalked or pedunculated forms) is described to Chilean deep waters. The specimen was collected in front of Iquique in Tarapacá Region of north Chile, associated to Patagonian Toothfish Dissostichus eleginoides fishery about 1000 m deep, and belong to a new species wish is the first record of the family Poecilasmatidae to Southeast Pacific. The genus Glyptelasma is composed by 12 species. G. chilensis is different from all known species because of the reduced peduncle in relation to the capitulum. It has a widening at the base and a minute tooth in the carinal plate. G. chilensis n. sp. is closely related to G. carinatum but differs from it in having only two filamentous appendages on the prosome. G. chilensis n. sp. has a basis of carina with extremes divergent and the wide is widest than the capitulum. The combinations of morphological characters allow the description of a new species for the genus Glyptelasma. With this first record to East Pacific of Glyptelasma, it could be inferred that the genus has a Tethyan distribution.
Se presentan los resultados preliminares de un procedimiento estandarizado para delimitar la zona estuarina mediante un árbol de decisiones sobre umbrales de histograma tomando como objeto de estudio el humedal del Río Limarí, un sitio RAMSAR, usando los índices satelitales NDVI (Normalized Difference Vegetation Index), NDWI (Normalized Difference Water Index), NDMI (Normalized Difference Moisture Index), VSSI (Vegetation Soil Salinity Index) y SWI (Salty Water Index); los que identificaron sus componentes vegetacionales, hidrológicos y sedimentarios, aportando desde el 85,27% al 38,04% de los píxeles en la solución final, en orden decreciente. Los resultados se optimizaron mediante un filtro ráster y selección vectorial, ofreciendo una nueva herramienta para la delimitación y discriminación del estuario bajo y la zona fluvial de este humedal.
Las diferentes condiciones que experimenta Caretta caretta durante su ciclo de vida, dada su longevidad y capacidad de migrar grandes distancias, se reflejan en cambios cuantitativos en la expresión de genes en los diferentes estadios, que pueden revelarse a través de análisis transcriptómico. Este estudio analiza la expresión diferencial de genes comparando transcriptomas de tortugas adultas y juveniles, enfocándose en genes relacionados con hipoxia y respuesta inmune. Se usaron secuencias de tortugas bajo cuidado profesional anidantes del Caribe colombiano, mapeadas y ensambladas empleando transcriptoma de referencia. Se cuantificó el nivel de expresión para el análisis diferencial y se realizó anotación funcional. Se identificaron 1.401 genes expresados diferencialmente (DEGs), con 507 sobre-expresados y 894 reprimidos en los adultos. Se anotaron funcionalmente ~40% de los DEGs, identificando 8.252 términos GO y 583 rutas KEGG, destacándose la respuesta inmunológica, el estrés oxidativo y el metabolismo de carbohidratos. En adultos, la tolerancia a hipoxia parece estar mediada por genes de respuesta al estrés oxidativo (CA3 y NKX3-1), mientras que en juveniles parece estar dada a genes de metabolismo de carbohidratos (ANGPTL4, HYI e IDH). Se observa una mayor expresión de respuesta inmunológica humoral en adultos (FAU, H2AJ y HA1F), y un mayor potencial de degradar compuestos xenobióticos en juveniles (CD69, CMBL y ETHE1). Las hipótesis planteadas basadas en la función y nivel de expresión de estos genes en cada estadio sobre las rutas metabólicas requieren investigación específica que considere variables no evaluadas en este estudio.
The morphology of the egg capsule and embryonic stages of Sympterygia brevicaudata are described. A total of 144 egg capsules were collected stranded on the beach and by scuba diving at a depth between 3 and 10 m, from Arica and Taltal, northern Chile, with a frequency of two days per month from March 2011 to March 2012 and from April 2012 to March 2013. The morphology and structures with which the female fixes the egg capsule to stable substrates are described. The observations on the late embryonic development were made using 72 embryos extracted from the 144 ovigerous capsules, which were kept in captivity. A total of seven embryonic stages were determined and described. In the initial stages (I to III) an embryo with an elongated structure was observed, with long and developed gill filaments, a translucent body and a pale pink color due to high blood supply and a large yolk sac. In later stages (IV to VII) the change in the morphology of the body disc was described due to the development of the pectoral and pelvic fins, appearance of ocular and body pigmentation, dorsal fins, dermal denticles and dorsal spines. The decrease and disappearance of the gill filaments and the yolk sac was documented. In conclusion, the detailed study of the egg capsule morphology and embryonic stages of S. brevicaudata provides a comprehensive insight into the early development of this species in coastal waters off northern Chile. Observations on egg capsule attachment and morphological changes during embryonic development highlight the adaptation and evolutionary process of this species in its natural habitat. This work contributes significantly to the understanding of reproductive biology and early development in rays of the genus Sympterygia, underlining the importance of conserving their ecosystem for preservation, especially in vulnerable species such as S. brevicaudata.
