Dr. Brante-Ramírez, Antonio

Athyonidium chilensis is a sea cucumber species that inhabits both the intertidal and subtidal zones of the southeast coast of the Pacific Ocean. This species is considered a commercially valuable fishery resource in Peru and Chile, which is exported to Asian countries for human consumption as a dried product. Despite its commercial importance, the spatial distribution of the genetic variability in A. chilensis along its geographic range remains unstudied. This information is crucial to define population stocks and to establish science-based management and conservation plans. Hence, our study aimed to assess the genetic structure and diversity of A. chilensis using DNA from adult specimens from six natural banks located between 18 °S and 42 °S. We analyzed 364 sequences from two genes (241 COI sequences and 123 ATPS-b sequences), which not only revealed high genetic diversity among A. chilensis populations from Chile but potentially also the presence of a second, cryptic species. Additionally, significant genetic distances were found among locations, with genetic flow decreasing with increasing spatial distance, suggesting different population stocks along the southeast coast of the Pacific Ocean. We provide crucial, baseline information to move forward with management plans for the preservation of genetic diversity for the species and the fishery to persist.

In pursuit of a more sustainable construction material with the potential to improve bioreceptivity in marine environments, this study investigates the feasibility of incorporating three industrial residues—steel sludge (“Conox”), mytilid mussel shells, and wheat straw fibers—as partial substitutes for cement and sand. The research focuses on evaluating the physical and mechanical properties of mortar and concrete mixtures containing these residues, both individually and in combination. Additionally, it assesses the metal leaching potential of concrete incorporating Conox sludges into the environment. The results show that mixture containing 10% Conox sludges as a sand substitute exhibit the highest mechanical strength but also increased porosity, water absorption, and chloride ion diffusion. The addition of mussel shells and straw fibers generally reduced mechanical properties and increased porosity in mortars, though a 20% mussel shell substitution maintained mechanical strength and chloride ion diffusion in the concrete. The combination of mussel shells with Conox sludges allowed the concrete to retain its mechanical properties, although it also increased porosity and chloride ion penetration, which may limit its use where impermeability is key. However, this increased porosity could benefit coastal erosion control structures like breakwaters and revetments, and sea walls. Moreover, metal leaching from concrete incorporating Conox sludges remained within established safety limits. Despite these challenges, the materials show promise for non-structural applications or projects where sustainability is prioritized. Our research lays the foundation and opens new possibilities for future investigations that innovate in the combination of industrial wastes, aiming to create more sustainable construction materials with a reduced impact on biodiversity.

The intertidal mussel Perumytilus purpuratus exhibits phenotypic plasticity in response to predation threats, with these responses influenced by the mussels' perception of predation risk. These adaptations, however, are constrained by energy costs and interactions with environmental factors that may trigger synergistic effects or trade-offs among different fitness traits. In particular, this study focuses on the anti-predatory responses of P. purpuratus against the sea star Meyenaster gelatinosus, examining how the presence of the predator and water flow strength influence these responses. The research was conducted through laboratory experiments, comparing mussels from two distinct localities with varying predation risks posed by M. gelatinosus: Punta Hualpén, where the predator is naturally present, and Coliumo, where it is absent. The anti-predatory responses were assessed by measuring attachment strength, byssus production, and adductor muscle mass in the presence of predator cues. Additionally, potential costs associated with these responses were estimated using the gonadosomatic index as a measure of reproductive investment. The findings indicate that the anti-predatory responses of P. purpuratus are contingent on the mussel's origin, with adhesion strength and byssus production negatively impacting reproductive investment. Moreover, the study highlights the intricate interplay of multiple factors, as evidenced by the complex adaptive mechanisms observed in P. purpuratus. The interaction between predator presence and water flow strength and their combined effects on various traits underscores the need for comprehensive multifactorial experiments to understand these adaptive processes. In conclusion, this study provided valuable insights into the nuanced and site-specific nature of anti-predatory responses in P. purpuratus. The research emphasizes the importance of considering multiple factors and conducting comprehensive experiments to unravel the intricacies of adaptive mechanisms in prey species.

Las especies del género Anisakis (Nematoda: Anisakidae) son parásitos marinos con ciclo de vida indirecto. Los crustáceos planctónicos actúan como primeros hospedadores intermediarios, mientras que peces y cefalópodos intervienen como segundos hospedadores intermediarios o paraténicos, finalmente el ciclo se cierra en los cetáceos, mamíferos marinos que son los principales hospedadores definitivos del género. En el ciclo de vida, las larvas de Anisakis pueden ser ingeridas por el hombre interviniendo como huésped accidental, lo que puede ocasionar anisakiasis, una zoonosis adquirida a través del consumo de peces y cefalópodos crudos o marinados. Estos nemátodos tienen una distribución cosmopolita, sin embargo, su diversidad ha sido escasamente estudiada en el hemisferio Sur. Por tanto, se evaluó la diversidad de las larvas de Anisakis spp., presentes en dos especies de hospederos de Chile, combinando el análisis morfométrico y genético. Para ello, se recolectaron larvas de Anisakis spp. en la cavidad abdominal de la merluza Merluccius gayi y el calamar Dosidicus gigas, procedentes de terminales pesqueros de la región del Biobío, Chile. La caracterización morfométrica de las larvas de Anisakis spp., consistió en la medición de la longitud del esófago, ventrículo esofágico, cola, longitud total y ancho máximo del cuerpo. Para los análisis genéticos se usó la región molecular nuclear ITS (ITS1-ITS2) y mitocondrial COX2. Los resultados morfométricos revelaron que las larvas extraídas de D. gigas son significativamente de mayor longitud que las recolectadas en M. gayi, sugiriendo una alta variabilidad fenotípica hospedador-dependiente. Los análisis moleculares y filogenéticos determinaron la presencia de Anisakis pegreffii en ambos hospedadores, sin embargo, demostraron una baja diferenciación genética y diversidad nucleotídica entre las secuencias, indicando una escasa variabilidad genética para el conjunto de datos. Este trabajo constituye el primer registro molecular de A. pegreffii en hospedadores intermediario o paraténicos de la costa de Chile.

Gorgonians (like corals) are important habitat-forming organisms that support a diversity of macrofauna. This study explored structural attributes of gorgonian gardens formed by rose gorgonians (Leptogorgia sp. nov.) and associated macrofaunal assemblages in Caleta Pichicuy (Central Chile). Hierarchical sampling was conducted at 20 m depth (maximum colony abundances) in order to assess spatial variability in abundance and colony attributes at two spatial scales (among sites and rocky walls). The abundance and composition of the associated vagile and sessile macrofauna were also examined using univariant (Taxa richness and Shannon index (H’e)) and multivariant approaches and were compared with adjacent bare rocky habitats. Our results showed a high abundance of gorgonians (ca. 28.9–36.5 colonies m−2) compared to other gorgonian gardens in the world. For structural attributes, our results showed smaller colonies with thicker holdfasts in more exposed sites, suggesting the influence of hydrodynamic forces on the colony morphology. Taxa richness and H’e of vagile fauna showed threefold and twofold, respectively, higher values in gorgonian gardens compared to bare walls, but no differences were observed for sessile fauna. In addition, PCoA and PERMANOVA evidenced a distinctive assemblages’ composition between habitats for both vagile and sessile fauna. Correlation analyzes and dbRDA showed, however, little association between structural attributes and associated faunal assemblages (R2 = 0.06, and ca. 3–9.4% of the total variation explained, respectively). Our results constitute the first assessment of structural habitat complexity and accompanying fauna in these gorgonian gardens and establish the baseline for understanding possible future changes associated to human activities.

The introduction and establishment of invasive species in regions outside their native range, is one of the major threats for the conservation of ecosystems, affecting native organisms and the habitat where they live in, causing substantial biological and monetary losses worldwide. Due to the impact of invasive species, it is important to understand what makes some species more invasive than others. Here, by simulating populations using a forward-in-time approach combining ecological and single polymorphic nucleotides (SNPs) we evaluated the relation between propagule size (number of individuals = 2, 10, 100, and 1,000), extinction rate (with values 2%, 5%, 10%, and 20%), and initial heterozygosity (0.1, 0.3, and 0.5) on the population survival and maintenance of the heterozygosity of a simulated invasive crab species over 30 generations assuming a single introduction. Our results revealed that simulated invasive populations with initial propagule sizes of 2–1,000 individuals experiencing a high extinction rate (10–20% per generation) were able to maintain over 50% of their initial heterozygosity during the first generations and that under scenarios with lower extinction rates invasive populations with initial propagule sizes of 10–1,000 individuals can survive up to 30 generations and maintain 60–100% of their initial heterozygosity. Our results can help other researchers better understand, how species with small propagule sizes and low heterozygosities can become successful invaders.

Genetic structure and connectivity information can be used to identify biological corridors and prioritize the conservation of areas that help maintain ecosystem integrity. Some marine fish, especially those of commercial interest, have been proposed as suitable indicators to identify potential marine biological corridors due to their high mobility among habitats and socioeconomic importance. In this study, we assessed the genetic structure of lane snapper populations in the Honduran Caribbean to evaluate connectivity and identify potential environmental barriers. Furthermore, we evaluated the genetic characteristics of the lane snapper on a larger spatial scale, including populations across the rest of its distribution range in the western Atlantic, using mtDNA and nuDNA markers. Our results demonstrate a significant genetic diversity of lane snappers in the Honduran Caribbean. Furthermore, despite their high dispersal potential, we observed genetic structuring in lane snapper populations on a larger spatial scale, resulting in the formation of two distinct groups throughout their distribution range: group 1 from Florida, the Gulf of Mexico, Honduras, and Colombia and group 2 from Puerto Rico and Brazil. This genetic differentiation can be attributed to oceanographic barriers such as river plumes and marine currents. These findings have the potential to significantly impact marine conservation and management efforts in the region, both at local and regional scales. It is anticipated that they will not only inform but also elicit a response, driving further action towards effective conservation measures. At a local scale, we recommend that conservation efforts focus on protecting critical habitats. At a regional scale, lane snappers should be included in the management plans of existing marine protected areas necessary to ensure the long-term sustainability of the species and the marine ecosystems in which it resides.

In coastal Antarctic environments, glacial meltwater changes the nutrients and physicochemical parameters in the water column. Consequently, top-down cascading effects are triggered throughout the food web, which can affect the bioenergetic condition of benthic invertebrates and their coupling processes between energy levels and flows throughout the marine food web. In this study, two benthic polychaetes (Maldane sarsi antarctica and Notomastus latericeus), exposed to the impact of glacial melting over a broad time scale, were used to evaluate the effect of glacial meltwater on their bioenergetic condition through the integrated analysis of: i) their biochemical composition; ii) fatty acid profiles and iii) total energy contents. The findings indicate that glacial meltwater has a direct effect on the bioenergetic condition of polychaetes. In areas where glacial meltwater has a significant impact, N. latericeus showed higher levels of proteins and glucose, but lower levels of lipids. On the other hand, M. sarsi antarctica exhibited decreased protein content with increasing glacial meltwater impact. M. sarsi antarctica presented varying levels of lipids across different sites, with the highest concentrations observed in areas with moderate impact. Both species showed a reduction in fatty acids with increasing glacial meltwater impact. Additionally, M. sarsi antarctica individuals from highly impacted areas had lower energy levels than those from less impacted areas, while N. latericeus had higher energy levels in the most impacted site. This information enables the development of a framework for assessing the impact of climate change using glacial meltwater and the integrated bioenergetics of key benthic polychaeta as a proxy. Therefore, identifying how glacial meltwater affects their bioenergetic condition helps us understand how climate change could affect trophic interactions, structure, and energy flows in the Antarctic marine food web.

Sea cucumbers are important sources of human food and pharmacological compounds. However, few studies have evaluated the potential differences between the sexes or organs in a particular species to explore new commercial opportunities. In this study, the proximate composition and amino acid profile of the body wall, the saponin content in the organs of Athyonidium chilensis males and females, and their cytotoxicity against colon cancer cells were evaluated. There were no significant differences in the proximate composition and amino acid profile of the body wall between the sexes. Protein content differed significantly between organs and sexes, fluctuating between 36.29 % and 72.98 % (dry weight). Saponin content was significantly higher in the gonads and lower in the longitudinal musculature. Cell viability was significantly lower (9.50 ± 2.23 %) with the digestive system saponin extract than with 40 % (94.75 ± 2.65 %). This work demonstrates the great potential of A. chilensis as a food and source of saponins with pharmacological importance.

Aim: Trait‐based approaches are powerful to examine the processes associated with biological invasions. Functional comparison among native and non‐indigenous species (NIS) can notably infer whether novel assemblages result from neutral or niche‐based assembly rules. Applying such a framework to biofouling communities, our study aimed to elucidate their distributions within two marine urban habitats (namely floating vs. nonfloating habitats). Location: Southeast Pacific—Central Chilean coastline. Methods: Here, we examined the distribution of 12 functional traits in fouling communities established on settlement plates, after 3 and 13 months of deployment in the two habitats and across ports in Central Chile. Based upon previously described differences of assemblages and NIS contribution across habitats, we hypothesized that nonindigenous, cryptogenic and native taxon pools would be functionally distinct (and trait biased), and that functional diversity and structure would vary across habitats and successional stages. Results: Our results show, as anticipated, that nonindigenous (13 taxa), cryptogenic (12) and native (18) taxon pools are functionally distinct, though overlapping in the trait space. Non‐indigenous species are rather related to colonizing traits, while native species are more related to competitive traits. Only one widespread NIS was functionally similar to the late successional and most competitive native species, including taxa elsewhere invasives. Despite differences in taxonomic composition between habitats, we did not observe functional differences between them. In contrast, temporal variations across colonization stages were detected along with an increased contribution in large and long‐lived taxa, together with site‐specific trajectories. Main Conclusions: We conclude that the functional distinctness among nonindigenous, cryptogenic and native taxa occupying artificial habitats in ports reflects niche‐based processes. Site‐specific trajectories indicate that scale‐dependent assembly processes, such as dispersal and species interactions, are at play.