Modeling the reproductive impact of aquaculture-produced sexually fertile triploids on conspecific diploid populations

Autores:

Winkler, F., Concha, M., & Concha, C.

Resumen:

The use of artificially produced triploid (3n) organisms has been proposed as a strategy to produce total or partial sterility in a number of species in order to prevent the potential negative effects of escapees on the genetic structure and integrity of wild conspecific populations or to avoid having alien species become feral in a new environment. When infertility is incomplete, triploid organisms are able to produce gametes that compete with those produced by wild diploid populations or crops that share the same habitat during reproductive periods, which may adversely affect the reproductive success of the wild population. In the present study, a model was developed in order to estimate the effects of the production of gametes by triploid organisms on the reproductive efficiency of a sympatric diploid population of the same species. The chance of the production of balanced gametes by triploids rapidly reduced with the increase of haploid number of the species. It was concluded that, in most aquatic species, this effect depends on the relative contribution of gametes derived from triploid individuals ( pet), which is determined by the proportion of triploids in the population and their relative fecundity relative to normal diploids. The variation of the reproductive efficiency in a mixed population of diploids and triploids will be directly proportional to pet if only one sex is fertile in triploids but will have a logarithmic relationship if both sexes are fertile.

Año: 2019

Palabras claves: Triploids, Risk assessment, Reproductive success, Sterility, Chromosome manipulation, Fecundity

Long-term persistence of the floating bull kelp Durvillaea antarctica from the South-East Pacific: Potential contribution to local and transoceanic connectivity

Autores:

Tala, F., López, B., Velásquez, M., Jeldres, R., Macaya, E., & Mansilla, A., Ojeda, J., Thiel, M.

Resumen:

Current knowledge about the performance of floating seaweeds as dispersal vectors comes mostly from mid latitudes (30°–40°), but phylogeographic studies suggest that long-distance dispersal (LDD) is more common at high latitudes (50°–60°). To test this hypothesis, long-term field experiments with floating southern bull kelp Durvillaea antarctica were conducted along a latitudinal gradient (30°S, 37°S and 54°S) in austral winter and summer. Floating time exceeded 200d in winter at the high latitudes but in summer it dropped to 90d, being still higher than at low latitudes (<45d). Biomass variations were due to loss of buoyant fronds. Reproductive activity diminished during long floating times. Physiological changes included mainly a reduction in photosynthetic (Fv/Fm and pigments) rather than in defence variables (phlorotannins and antioxidant activity). The observed long floating persistence and long-term acclimation responses at 54°S support the hypothesis of LDD by kelp rafts at high latitudes.

Año: 2019

Palabras claves: Chile, Durvillaea antarctica, Floating persistence, Rafting, Dispersal, Floating seaweeds, Temperature

How Does the Diversity of Divers Affect the Design of Citizen Science Projects?

Autores:

Hermoso, M., Martin, V., Stotz, W., Gelcich, S., & Thiel, M.

Resumen:

Divers have widely participated in citizen science (CS) projects and are one of the main groups of marine citizen scientists. However, there is little knowledge about profiles of, and incentives for potential divers to join CS projects. To date, most studies have focused on the SCUBA diving industry; nevertheless, there is a diversity of divers, not all using SCUBA, who engage in different activities during their dives. Differences in diver profiles could affect their willingness and ability to contribute to CS. In this study, we compare the diving profile, interests, preferences and motivations to participate in CS of five diver types (artisanal fishermen, recreational divers, instructors, scientific divers, and others). All divers have strong interests in participating in CS projects, with no major differences among diver types. In general, they are interested in a wide variety of themes related to CS but they prefer simple sampling protocols. Divers are motivated to participate in CS to learn about the sea and contribute to science. Some important differences among diver types were found, with artisanal fishermen having significantly more dive experience than other diver types, but less free time during their dives and limited access to some communication channels and technologies. These characteristics make them ideal partners to contribute their local ecological knowledge (LEK) to local CS projects. In contrast, recreational divers have the least experience but most free time during their dives and good access to cameras and communications channels, making them suitable partners for large-scale CS projects that do not require a high level of species knowledge. Instructors and scientific divers are well-placed to coordinate and supervise CS activities. The results confirm that divers are not all alike and specific considerations have to be taken into account to improve the contribution of each diver type to CS. The findings provide essential information for the design of different types of CS projects. By considering the relevant incentives and opportunities for diverse diver groups, marine CS projects will make efficient gains in volunteer recruitment, retention, and collaborative generation of knowledge about the marine environment.

Año: 2019

Palabras claves: Participatory science, subtidal, SCUBA, fishermen, recreational divers.

Uncovering population structure in the Humboldt penguin (Spheniscus humboldti) along the Pacific coast at South America

Autores:

Dantas, G., Oliveira, L., Santos, A., Flores, M., Melo, D., Simeone, A., González-Acuña, D., Luna-Jorquera, G., Le Bohec, C., Valdés-Velásquez, A., Cardeña, M., Morgante, J.S., Vianna, J.A.

Resumen:

The upwelling hypothesis has been proposed to explain reduced or lack of population structure in seabird species specialized in food resources available at cold-water upwellings. However, population genetic structure may be challenging to detect in species with large population sizes, since variation in allele frequencies are more robust under genetic drift. High gene flow among populations, that can be constant or pulses of migration in a short period, may also decrease power of algorithms to detect genetic structure. Penguin species usually have large population sizes, high migratory ability but philopatric behavior, and recent investigations debate the existence of subtle population structure for some species not detected before. Previous study on Humboldt penguins found lack of population genetic structure for colonies of Punta San Juan and from South Chile. Here, we used mtDNA and nuclear markers (10 microsatellites and RAG1 intron) to evaluate population structure for 11 main breeding colonies of Humboldt penguins, covering the whole spatial distribution of this species. Although mtDNA failed to detect population structure, microsatellite loci and nuclear intron detected population structure along its latitudinal distribution. Microsatellite showed significant Rst values between most of pairwise locations (44 of 56 locations, Rst = 0.003 to 0.081) and 86% of individuals were assigned to their sampled colony, suggesting philopatry. STRUCTURE detected three main genetic clusters according to geographical locations: i) Peru; ii) North of Chile; and iii) Central-South of Chile. The Humboldt penguin shows signal population expansion after the Last Glacial Maximum (LGM), suggesting that the genetic structure of the species is a result of population dynamics and foraging colder water upwelling that favor gene flow and phylopatric rate. Our findings thus highlight that variable markers and wide sampling along the species distribution are crucial to better understand genetic population structure in animals with high dispersal ability.

Año: 2019

Palabras claves: Penguins, Population genetics, Animal sociality, Chile (country), Gene flow, Islands, Seabirds, Haplotypes

Esculturas de acero: observaciones de corrosión e inhibición mediante una cámara de niebla salina, sensores y un microscopio de bajo costo

Autores:

Novoa Jerez, J., Alfaro Guerra, M., & Alfaro Alcaíno, I.

Resumen:

La presencia de partículas de NaCl en el aerosol marino produce corrosión en esculturas de acero de interés patrimonial, valor artístico y arquitectónico. Es aquí donde la observación de la corrosión utilizando una cámara de neblina, sensores y un microscopio de bajo costo podría permitir su estudio, junto con la ventaja de poder desarrollar proyectos en conjunto entre carreras de Pedagogía en Química con carreras de Pedagogía en Historia y Geografía y Pedagogía en Matemáticas y Computación, además del estudio de las propiedades anticorrosivas de Metamizol frente al acero al carbono sometido al aerosol marino en la cámara de neblina mediante la utilización de fotomicrografías.

Año: 2019

Palabras claves: Corrosión atmosférica, Aerosol marino, Esculturas de acero, Cámara de neblina, Sensores, Microscopio de bajo costo.

Unexpected population fragmentation in an endangered seabird: the case of the Peruvian diving-petrel

Autores:

Cristofari, R., Plaza, P., Fernández, C., Trucchi, E., Gouin, N., Le Bohec, C., Zavalaga, C., Alfaro-Shigueto, J., Luna-Jorquera, G.

Resumen:

In less than one century, the once-abundant Peruvian diving petrel has become the first endangered seabird of the Humboldt Current System (HCS). This small endemic petrel of the South American Pacific coast is now an important indicator of ongoing habitat loss and of the success of local conservation policies in the HCS - an ecoregion designated as a priority for the conservation of global biodiversity. Yet so far, poorly understood life history traits such as philopatry or dispersal ability may strongly influence the species’ response to ecosystem changes, but also our capacity to assess and interpret this response. To address this question, we explore the range-wide population structure of the Peruvian diving petrel, and show that this small seabird exhibits extreme philopatric behavior at the island level. Mitochondrial DNA sequences and genome-wide SNP data reveal significant isolation and low migration at very short distances, and provide strong evidence for questioning the alleged recovery in the Peruvian and Chilean populations of this species. Importantly, the full demographic independence between colonies makes local population rescue through migration unlikely. As a consequence, the Peruvian diving petrel appears to be particularly vulnerable to ongoing anthropogenic pressure. By excluding immigration as a major factor of demographic recovery, our results highlight the unambiguously positive impact of local conservation measures on breeding populations; yet at the same time they also cast doubt on alleged range-wide positive population trends. Overall, the protection of independent breeding colonies, and not only of the species as a whole, remains a major element in the conservation strategy for endemic seabirds. Finally, we underline the importance of considering the philopatric behavior and demographic independence of breeding populations, even at very fine spatial scales, in spatial planning for marine coastal areas.

Año: 2019

Palabras claves:

“Citizen Science Among All” Participatory Bird Monitoring of the Coastal Wetland of the Limarí River, Chile

Autores:

Nuñez-Farias, P., Velásquez-Contreras, S., Ríos-Carmona, V., Velásquez-Contreras, J., Velásquez-Contreras, M., Rojas-Rojas, J., & Riveros-Flores, B.

Resumen:

We are a group of young people interested in the protection of the coastal wetland of the Limarí River, located south of the Atacama Desert in Chile. Since 2016, we have conducted participatory monitoring to analyze the [End Page E3] diversity of wetland birds in the Fray Jorge Biosphere Reserve. The reserve is a habitat for migratory and resident birds of national and international importance. However, this wetland faces constant anthropogenic threats, such as garbage accumulation, vehicle traffic, hunting of native fauna, among other problems. Citizen science has been our tool of choice to generate relevant information about this natural ecosystem, to enjoy and protect the wetland, to co-create strategies to improve human practices in the natural environment. Together with birdwatchers, scientists and naturalists, we have generated a list of 70 bird species for the site, quantifying the seasonal changes in richness and abundance of wetland species. But, the best results have been for each of the team members: during each visit to the wetland, we make new friends, we have a lot of fun, and we learn together about nature. This experience has empowered us to communicate with the inhabitants of the locality and to the state agencies why we should all take care of our coastal wetlands.

The above describes our local treasure, and we want to share the characteristics, acquired learning, and a little of the magic that makes this group unique in order to inform protagonists, students, regulators, and followers of citizen science.

Año: 2019

Palabras claves:

Similarity in predator-specific anti-predator behavior in ecologically distinct limpet species, Scurria viridula (Lottiidae) and Fissurella latimarginata (Fissurellidae)

Autores:

Aguilera, M., Weiß, M., & Thiel, M.

Resumen:

Many marine gastropods show species-specific behavioral responses to different predators, but less is known about the mechanisms influencing differences or similarities in specific responses. Herein, we examined whether two limpet species, Scurria viridula (Lamarck, 1819) and Fissurella latimarginata (Sowerby, 1835), show species- and size-specific similarities or differences in their reaction to predatory seastars and crabs. Both S. viridula and F. latimarginata reacted to their main seastar predators with escape responses. In contrast, both limpets did not flee from common crab predators, but, instead, fastened to the rock. All tested size classes of both limpet species reacted in a similar way, escaping from seastars, but clamping onto the rock in response to crabs. Limpets could reach velocities sufficient to outrun their specific seastar predators, but they were not fast enough to escape crabs. Experiments with limpets of different shell conditions (with and without shell damage) indicated that F. latimarginata with a damaged shell showed “accommodation movements” (slow movements away from stimulus) in response to predatory crabs. In contrast, intact F. latimarginata and all S. viridula (intact and damaged) clamped the shell down to the substratum. The response details suggest that the keyhole limpet F. latimarginata is more sensitive to predators (faster reaction time, longer escape distances, and higher proportion of reacting individuals) than S. viridula, possibly because the morphology of F. latimarginata (the relationship of its shell size and structure to its total body size) makes this species more vulnerable to predation. Our study suggests that chemically mediated effects of seastar and crab predators result in contrasting behavioral responses of both limpet species, independent of their habitat and morphology. Despite the different characteristics of the limpet species and the identity of predators, the limpets react in comparable ways to similar predator types.

Año: 2019

Palabras claves:

Antarctic Extremophiles: Biotechnological Alternative to Crop Productivity in Saline Soils

Autores:

Acuña-Rodríguez, I., Hansen, H., Gallardo-Cerda, J., Atala, C., & Molina-Montenegro, M.

Resumen:

Salinization of soils is one of the main sources of soil degradation worldwide, particularly in arid and semiarid ecosystems. High salinity results in osmotic stress and it can negatively impact plant grow and survival. Some plant species, however, can tolerate salinity by accumulating osmolytes like proline and maintaining low Na+ concentrations inside the cells. Another mechanism of saline stress tolerance is the association with symbiotic microorganism, an alternative that can be used as a biotechnological tool in susceptible crops. From the immense diversity of plant symbionts, those found in extreme environments such as Antarctica seems to be the ones with most potential since they (and their host) evolved in harsh and stressful conditions. We evaluated the effect of the inoculation with a consortium of plant growth-promoting rhizobacteria (PGPB) and endosymbiotic fungi isolated from an Antarctic plant on saline stress tolerance in different crops. To test this we established 4 treatments: (i) uninoculated plants with no saline stress, (ii) uninoculated plants subjected to saline stress (200 mM NaCl), (iii) plants inoculated with the microorganism consortium with no saline stress, and (iv) inoculated plants subjected to saline stress. First, we assessed the effect of symbiont consortium on survival of four different crops (cayenne, lettuce, onion, and tomato) in order to obtain a more generalized response of this biological interaction. Second, in order to deeply the mechanisms involved in salt tolerance, in lettuce plants we measured the ecophysiological performance (Fv/Fm) and lipid peroxidation to estimate the impact of saline stress on plants. We also measured proline accumulation and NHX1 antiporter gene expression (involved in Na+ detoxification) to search for possible mechanism of stress tolerance. Additionally, root, shoot, and total biomass was also obtained as an indicator of productivity. Overall, plants inoculated with microorganisms from Antarctica increased the fitness related traits in several crops. In fact, three of four crops selected to assess the general response increased its survival under salt conditions compared with those uninoculated plants. On the other hand, saline stress negatively impacted all measured trait, but inoculated plants were significantly less affected. In control osmotic conditions, there were no differences in proline accumulation and lipid peroxidation between inoculation treatments. Interestingly, even in control salinity, Fv/Fm was higher in inoculated plants after 30 and 60 days. Under osmotic stress, Fv/Fm, proline accumulation and NHX1 expression was significantly higher and lipid peroxidation lower in inoculated plants compared to uninoculated individuals. Moreover, inoculated plants exposed to saline stress had a similar final biomass (whole plant) compared to individuals under no stress. We conclude that Antarctic extremophiles can effectively reduce the physiological impact of saline stress in a salt-susceptible crops and also highlight extreme environments such as Antarctica as a key source of microorganism with high biotechnological potential.

Año: 2019

Palabras claves: Extremophiles, Antarctica, functional symbiosis, crops, food security, salt tolerance

Aves marinas varadas en la bahía de Coquimbo, norte de Chile: ¿Qué especies y cuántas mueren?

Autores:

Portflitt Toro, M., Miranda Urbina, D., & Luna Jorquera, G.

Resumen:

El monitoreo de las aves varadas en las playas puede proporcionar información sobre sus causas de muerte, tales como la captura incidental en actividades de pesca o derrames de petróleo. Durante un año fue monitoreada mensualmente la Bahía de Coquimbo, norte de Chile para cuantificar el número de aves marinas varadas. Se encontraron 395 aves marinas muertas de las cuales 382 fueron identificadas y agrupadas en 21 especies. Las especies más abundantes fueron los piqueros con 115 individuos (30%), el cormorán guanay con 83 individuos (22%) y la gaviota dominicana con 65 individuos (17%). Las especies más abundantes y frecuentes fueron las que anidan en el Sistema Costero de Coquimbo. La mortalidad afecta principalmente a las aves marinas que se alimentan de la anchoveta, que es el principal recurso objetivo de la pesca con redes de cerco. Se sugiere que la mortalidad incidental causada por la pesca es crónica y relativamente constante durante el año. Se requiere un programa de monitoreo a largo plazo para mejorar la estimación de la mortalidad y los factores que influyen en la interacción de las aves marinas con las artes de pesca.

Monitoring of seabirds stranded on beaches can provide information about their causes of death, such as bycatch in fishing activities or oil spills. During a year we monthly monitored the Coquimbo Bay, north Chile, to quantify the number of seabirds and species stranded. We found 395 dead seabirds, of which 382 were identified and grouped into 21 species. The most abundant were the Peruvian booby with 115 individuals (30%), the Guanay cormorant with 83 individuals (22%) and the Kelp gull with 65 individuals (17%). The most abundant and frequent species were those nesting in the Coastal System of Coquimbo. Mortality mainly affected seabirds that feed on anchoveta, which is the main target resource of purse seine fishing. We suggest that the incidental mortality caused by fishing is chronic and relatively constant during the year. A long-term monitoring program is needed to better estimate the mortality and the factors that influence the interaction of seabirds with fishing gears.

Año: 2018

Palabras claves: Strandings; seabirds; Suliformes; Coastal System of Coquimbo; Chile